【lombok】lombok---幫你簡化生成必要但臃腫的java代碼工具【映射注解和lombok注解同時使用以及映射注解放在屬性和get方法上的區別】

本文轉載自查看原文 2017-11-23 13:32 4087 lombok

官方地址：https://projectlombok.org/

GitHub:https://github.com/rzwitserloot/lombok

指導說明文檔：http://jnb.ociweb.com/jnb/jnbJan2010.html

===============================================================================================================

本來來說，lombok作為一個目前為止【2017-11-27】java並未將其作為標准來推廣。還有很多人問使用它是否合適。

這里不做這種討論！！！

===============================================================================================================

在使用之前，要明確一點，在開發過程中，一般情況下，僅使用@Data 即可滿足生成entity類的大部分情況。

摘自指導文檔：

Essentially, using @Data on a class is the same as annotating the class with a default @ToString and @EqualsAndHashCode as well as annotating each field with both @Getter and @Setter.

實質上，在一個類上使用@Data與用默認的@ToString和@EqualsAndHashCode注釋這個類以及用@Getter和@Setter注釋每個字段是一樣的。

===============================================================================================================

使用起來：

一.安裝lombok插件【idea使用為例】

二.項目引入lombok依賴

        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

版本這里不給了，想使用最新版本的，可以自己加上。

三.lombok注解使用詳解

在上面安裝插件的時候，可以看到有很多的注解是被支持的：

官方的指導文檔，時間久遠。所以就找到下面的注解進行詳解。

@Getter and @Setter

【屬性級別，生成本屬性的get和set方法】

AccessLevel.PROTECTED　　默認生成的方法為public，此屬性可以設置生成方法的訪問修飾符【非必須】

轉化前：

package com.sxd.entity;


import lombok.AccessLevel;
import lombok.Getter;
import lombok.Setter;

public class Order {

   @Getter @Setter private String orderId;
   @Getter(AccessLevel.PROTECTED) @Setter  private User user;
   @Getter @Setter(AccessLevel.NONE) private String productName;

}

View Code

編譯后：

package com.sxd.entity;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public void setOrderId(String orderId)
  {
    this.orderId = orderId;
  }
  
  public String getOrderId()
  {
    return this.orderId;
  }
  
  public void setUser(User user)
  {
    this.user = user;
  }
  
  protected User getUser()
  {
    return this.user;
  }
  
  public String getProductName()
  {
    return this.productName;
  }
}

View Code

=============================================================================

@ToString

【類級別，生成自定義的toString()方法】

exclude="｛字段1，字段2｝"　　生成的toString（）不包含哪些字段【非必須】

callSuper=true　　如果繼承的有父類的話，可以設置callSuper 讓其調用父類的toString()方法【非必須】

轉化前：

package com.sxd.entity;


import lombok.ToString;

@ToString(exclude = {"orderId","user"},callSuper = false)
public class Order {

    private String orderId;
    private User user;
    private String productName;

}

View Code

編譯后：

package com.sxd.entity;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public String toString()
  {
    return "Order(productName=" + this.productName + ")";
  }
}

View Code

不使用上述屬性值的話：

轉化前：

package com.sxd.entity;


import lombok.ToString;

@ToString
public class Order {

    private String orderId;
    private User user;
    private String productName;


}

View Code

編譯后：

package com.sxd.entity;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public String toString()
  {
    return "Order(orderId=" + this.orderId + ", user=" + this.user + ", productName=" + this.productName + ")";
  }
}

View Code

===================================================================================

@EqualsAndHashCode

【類級別，生成自定義的equals()方法和HashCode()方法】

exclude="｛字段1，字段2｝"　　生成的方法不包含哪些字段【非必須】

callSuper=true　　如果繼承的有父類的話，可以設置callSuper 讓其調用父類的方法【非必須】

轉化前：

package com.sxd.entity;


import lombok.EqualsAndHashCode;

@EqualsAndHashCode(exclude = {"orderId","user"},callSuper = false)
public class Order {

    private String orderId;
    private User user;
    private String productName;

}

View Code

編譯后：

package com.sxd.entity;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public int hashCode()
  {
    int PRIME = 59;int result = 1;Object $productName = this.productName;result = result * 59 + ($productName == null ? 43 : $productName.hashCode());return result;
  }
  
  protected boolean canEqual(Object other)
  {
    return other instanceof Order;
  }
  
  public boolean equals(Object o)
  {
    if (o == this) {
      return true;
    }
    if (!(o instanceof Order)) {
      return false;
    }
    Order other = (Order)o;
    if (!other.canEqual(this)) {
      return false;
    }
    Object this$productName = this.productName;Object other$productName = other.productName;return this$productName == null ? other$productName == null : this$productName.equals(other$productName);
  }
}

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=====================================================================================

@NonNull

【屬性級別，驗證不能為null的注解，如果執行加了這個注解的setter方法時設置為Null，拋異常java.lang.NullPointerException】

轉化前：

package com.sxd.entity;


import lombok.Getter;
import lombok.NonNull;
import lombok.Setter;

public class Order {

    private String orderId;
    private User user;
    @NonNull @Getter @Setter private String productName;

    public Order() {

    }

}

View Code

編譯后：

package com.sxd.entity;

import lombok.NonNull;

public class Order
{
  private String orderId;
  private User user;
  @NonNull
  private String productName;
  
  public void setProductName(@NonNull String productName)
  {
    if (productName == null) {
      throw new NullPointerException("productName");
    }
    this.productName = productName;
  }
  
  @NonNull
  public String getProductName()
  {
    return this.productName;
  }
}

View Code

如果去執行setter方法並賦值Null,則報錯：

注意報錯行數：

===========================================================================================

@NoArgsConstructor

【類級別，生成無參構造方法】

　focus=true　　當類中有final字段沒有被初始化時，編譯器會報錯，此時可用@NoArgsConstructor(force = true)，然后就會為沒有初始化的final字段設置默認值 0 / false / null。對於具有約束的字段（例如@NonNull字段），不會生成檢查或分配，因此請注意，正確初始化這些字段之前，這些約束無效。

轉化前：

package com.sxd.entity;

import lombok.NoArgsConstructor;

@NoArgsConstructor(force = true)
public class Order {
    private String orderId;
    private User user;
    private String productName;

}

View Code

編譯后：

package com.sxd.entity;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
}

View Code

=====================================================================================

@RequiredArgsConstructor

【類級別，生成有或無參的靜態方法，用於獲取本對象】

staticName = "自定義靜態方法名"

轉化前：

package com.sxd.entity;


import lombok.RequiredArgsConstructor;

@RequiredArgsConstructor(staticName = "build")
public class Order {
    private String orderId;
    private User user;
    private String productName;

}

View Code

轉化后：

package com.sxd.entity;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public static Order build()
  {
    return new Order();
  }
}

View Code

===============================================================================

@AllArgsConstructor

【類級別，生成全參構造方法】

轉化前：

package com.sxd.entity;


import lombok.AllArgsConstructor;

@AllArgsConstructor
public class Order {
    private String orderId;
    private User user;
    private String productName;

}

View Code

編譯后：

package com.sxd.entity;

import java.beans.ConstructorProperties;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  @ConstructorProperties({"orderId", "user", "productName"})
  public Order(String orderId, User user, String productName)
  {
    this.orderId = orderId;this.user = user;this.productName = productName;
  }
}

View Code

================================================================================

@Data

【類級別，此注解為lombok中最常用注解】

【@Data 包含了@ToString，@EqualsAndHashCode，@Getter / @Setter和@RequiredArgsConstructor的功能】

staticConstructor="靜態實例化方法名"

轉化前：

package com.sxd.entity;


import lombok.Data;

@Data(staticConstructor = "build")
public class Order {
    private String orderId;
    private User user;
    private String productName;

}

View Code

編譯后：

package com.sxd.entity;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public static Order build()
  {
    return new Order();
  }
  
  public int hashCode()
  {
    int PRIME = 59;int result = 1;Object $orderId = getOrderId();result = result * 59 + ($orderId == null ? 43 : $orderId.hashCode());Object $user = getUser();result = result * 59 + ($user == null ? 43 : $user.hashCode());Object $productName = getProductName();result = result * 59 + ($productName == null ? 43 : $productName.hashCode());return result;
  }
  
  protected boolean canEqual(Object other)
  {
    return other instanceof Order;
  }
  
  public boolean equals(Object o)
  {
    if (o == this) {
      return true;
    }
    if (!(o instanceof Order)) {
      return false;
    }
    Order other = (Order)o;
    if (!other.canEqual(this)) {
      return false;
    }
    Object this$orderId = getOrderId();Object other$orderId = other.getOrderId();
    if (this$orderId == null ? other$orderId != null : !this$orderId.equals(other$orderId)) {
      return false;
    }
    Object this$user = getUser();Object other$user = other.getUser();
    if (this$user == null ? other$user != null : !this$user.equals(other$user)) {
      return false;
    }
    Object this$productName = getProductName();Object other$productName = other.getProductName();return this$productName == null ? other$productName == null : this$productName.equals(other$productName);
  }
  
  public void setOrderId(String orderId)
  {
    this.orderId = orderId;
  }
  
  public void setUser(User user)
  {
    this.user = user;
  }
  
  public void setProductName(String productName)
  {
    this.productName = productName;
  }
  
  public String toString()
  {
    return "Order(orderId=" + getOrderId() + ", user=" + getUser() + ", productName=" + getProductName() + ")";
  }
  
  public String getOrderId()
  {
    return this.orderId;
  }
  
  public User getUser()
  {
    return this.user;
  }
  
  public String getProductName()
  {
    return this.productName;
  }
}

View Code

@Accessors

【類級別，控制get、set方法】

fluent　　 boolean值，默認為false。此字段主要為控制生成的getter和setter方法前面是否帶get/set；false帶，true不帶
chain 　　boolean值，默認false。如果設置為true，setter返回的是此對象，方便鏈式調用方法
prefix 　　設置前綴例如：@Accessors(prefix = "abc") private String abcAge 當生成get/set方法時，會把此前綴去掉

轉化前：【注意三個屬性設值以及生成】

package com.sxd.entity;


import lombok.Data;
import lombok.experimental.Accessors;

@Data
@Accessors(fluent = false,chain = false,prefix = "aaa")
public class Order {
    private String orderId;
    private User user;
    private String productName;

}

View Code

編譯后：

package com.sxd.entity;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public String toString()
  {
    return "Order(orderId=" + this.orderId + ", user=" + this.user + ", productName=" + this.productName + ")";
  }
  
  public int hashCode()
  {
    int PRIME = 59;int result = 1;Object $orderId = this.orderId;result = result * 59 + ($orderId == null ? 43 : $orderId.hashCode());Object $user = this.user;result = result * 59 + ($user == null ? 43 : $user.hashCode());Object $productName = this.productName;result = result * 59 + ($productName == null ? 43 : $productName.hashCode());return result;
  }
  
  protected boolean canEqual(Object other)
  {
    return other instanceof Order;
  }
  
  public boolean equals(Object o)
  {
    if (o == this) {
      return true;
    }
    if (!(o instanceof Order)) {
      return false;
    }
    Order other = (Order)o;
    if (!other.canEqual(this)) {
      return false;
    }
    Object this$orderId = this.orderId;Object other$orderId = other.orderId;
    if (this$orderId == null ? other$orderId != null : !this$orderId.equals(other$orderId)) {
      return false;
    }
    Object this$user = this.user;Object other$user = other.user;
    if (this$user == null ? other$user != null : !this$user.equals(other$user)) {
      return false;
    }
    Object this$productName = this.productName;Object other$productName = other.productName;return this$productName == null ? other$productName == null : this$productName.equals(other$productName);
  }
}

View Code

===========================================================

轉化前：【注意fluent】

package com.sxd.entity;


import lombok.Data;
import lombok.experimental.Accessors;

@Data
@Accessors(fluent = true,chain = false)
public class Order {
    private String orderId;
    private User user;
    private String productName;

}

View Code

編譯后：

package com.sxd.entity;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public void productName(String productName)
  {
    this.productName = productName;
  }
  
  public int hashCode()
  {
    int PRIME = 59;int result = 1;Object $orderId = orderId();result = result * 59 + ($orderId == null ? 43 : $orderId.hashCode());Object $user = user();result = result * 59 + ($user == null ? 43 : $user.hashCode());Object $productName = productName();result = result * 59 + ($productName == null ? 43 : $productName.hashCode());return result;
  }
  
  protected boolean canEqual(Object other)
  {
    return other instanceof Order;
  }
  
  public void orderId(String orderId)
  {
    this.orderId = orderId;
  }
  
  public void user(User user)
  {
    this.user = user;
  }
  
  public String toString()
  {
    return "Order(orderId=" + orderId() + ", user=" + user() + ", productName=" + productName() + ")";
  }
  
  public boolean equals(Object o)
  {
    if (o == this) {
      return true;
    }
    if (!(o instanceof Order)) {
      return false;
    }
    Order other = (Order)o;
    if (!other.canEqual(this)) {
      return false;
    }
    Object this$orderId = orderId();Object other$orderId = other.orderId();
    if (this$orderId == null ? other$orderId != null : !this$orderId.equals(other$orderId)) {
      return false;
    }
    Object this$user = user();Object other$user = other.user();
    if (this$user == null ? other$user != null : !this$user.equals(other$user)) {
      return false;
    }
    Object this$productName = productName();Object other$productName = other.productName();return this$productName == null ? other$productName == null : this$productName.equals(other$productName);
  }
  
  public String orderId()
  {
    return this.orderId;
  }
  
  public User user()
  {
    return this.user;
  }
  
  public String productName()
  {
    return this.productName;
  }
}

View Code

==============================================================================

轉化前：【注意chain】

package com.sxd.entity;


import lombok.Data;
import lombok.experimental.Accessors;

@Data
@Accessors(fluent = false,chain = true)
public class Order {
    private String orderId;
    private User user;
    private String productName;

}

View Code

編譯后：

package com.sxd.entity;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public Order setProductName(String productName)
  {
    this.productName = productName;return this;
  }
  
  public int hashCode()
  {
    int PRIME = 59;int result = 1;Object $orderId = getOrderId();result = result * 59 + ($orderId == null ? 43 : $orderId.hashCode());Object $user = getUser();result = result * 59 + ($user == null ? 43 : $user.hashCode());Object $productName = getProductName();result = result * 59 + ($productName == null ? 43 : $productName.hashCode());return result;
  }
  
  protected boolean canEqual(Object other)
  {
    return other instanceof Order;
  }
  
  public Order setOrderId(String orderId)
  {
    this.orderId = orderId;return this;
  }
  
  public Order setUser(User user)
  {
    this.user = user;return this;
  }
  
  public String toString()
  {
    return "Order(orderId=" + getOrderId() + ", user=" + getUser() + ", productName=" + getProductName() + ")";
  }
  
  public boolean equals(Object o)
  {
    if (o == this) {
      return true;
    }
    if (!(o instanceof Order)) {
      return false;
    }
    Order other = (Order)o;
    if (!other.canEqual(this)) {
      return false;
    }
    Object this$orderId = getOrderId();Object other$orderId = other.getOrderId();
    if (this$orderId == null ? other$orderId != null : !this$orderId.equals(other$orderId)) {
      return false;
    }
    Object this$user = getUser();Object other$user = other.getUser();
    if (this$user == null ? other$user != null : !this$user.equals(other$user)) {
      return false;
    }
    Object this$productName = getProductName();Object other$productName = other.getProductName();return this$productName == null ? other$productName == null : this$productName.equals(other$productName);
  }
  
  public String getOrderId()
  {
    return this.orderId;
  }
  
  public User getUser()
  {
    return this.user;
  }
  
  public String getProductName()
  {
    return this.productName;
  }
}

View Code

===================================================================

轉化前：【注意prefix】

package com.sxd.entity;


import lombok.Data;
import lombok.experimental.Accessors;

@Data
@Accessors(fluent = false,chain = true,prefix = "product")
public class Order {
    private String orderId;
    private User user;
    private String productName;

}

View Code

編譯后：

package com.sxd.entity;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public String toString()
  {
    return "Order(orderId=" + this.orderId + ", user=" + this.user + ", productName=" + getName() + ")";
  }
  
  public int hashCode()
  {
    int PRIME = 59;int result = 1;Object $orderId = this.orderId;result = result * 59 + ($orderId == null ? 43 : $orderId.hashCode());Object $user = this.user;result = result * 59 + ($user == null ? 43 : $user.hashCode());Object $productName = getName();result = result * 59 + ($productName == null ? 43 : $productName.hashCode());return result;
  }
  
  protected boolean canEqual(Object other)
  {
    return other instanceof Order;
  }
  
  public boolean equals(Object o)
  {
    if (o == this) {
      return true;
    }
    if (!(o instanceof Order)) {
      return false;
    }
    Order other = (Order)o;
    if (!other.canEqual(this)) {
      return false;
    }
    Object this$orderId = this.orderId;Object other$orderId = other.orderId;
    if (this$orderId == null ? other$orderId != null : !this$orderId.equals(other$orderId)) {
      return false;
    }
    Object this$user = this.user;Object other$user = other.user;
    if (this$user == null ? other$user != null : !this$user.equals(other$user)) {
      return false;
    }
    Object this$productName = getName();Object other$productName = other.getName();return this$productName == null ? other$productName == null : this$productName.equals(other$productName);
  }
  
  public Order setName(String productName)
  {
    this.productName = productName;return this;
  }
  
  public String getName()
  {
    return this.productName;
  }
}

View Code

=========================================================================

@Cleanup

【代碼級別，清理資源/關閉資源注解】

轉化前：

public void testCleanUp() {
    try {
        @Cleanup ByteArrayOutputStream baos = new ByteArrayOutputStream();
        baos.write(new byte[] {'Y','e','s'});
        System.out.println(baos.toString());
    } catch (IOException e) {
        e.printStackTrace();
    }
}

View Code

編譯后：

public void testCleanUp() {
    try {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            baos.write(new byte[]{'Y', 'e', 's'});
            System.out.println(baos.toString());
        } finally {
            baos.close();
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}

View Code

=========================================================================

@Synchronized

【方法級別，同步/線程安全注解】

轉化前：

private DateFormat format = new SimpleDateFormat("MM-dd-YYYY");

@Synchronized
public String synchronizedFormat(Date date) {
    return format.format(date);
}

View Code

編譯后：

private final java.lang.Object $lock = new java.lang.Object[0];
private DateFormat format = new SimpleDateFormat("MM-dd-YYYY");

public String synchronizedFormat(Date date) {
    synchronized ($lock) {
        return format.format(date);
    }
}

View Code

=========================================================================

@Wither

【屬性級別，提供了給final字段賦值的一種方法】

轉化前：

import lombok.AccessLevel;
import lombok.NonNull;
import lombok.experimental.Wither;
public class WitherExample {
@Wither private final int age;
@Wither(AccessLevel.PROTECTED) @NonNull private final String name;

public WitherExample(String name, int age) {
  if (name == null) throw new NullPointerException();
  this.name = name;
  this.age = age;
}
}

View Code

編譯后：

import lombok.NonNull;
public class WitherExample {
private final int age;
private @NonNull final String name;

public WitherExample(String name, int age) {
  if (name == null) throw new NullPointerException();
  this.name = name;
  this.age = age;
}

public WitherExample withAge(int age) {
  return this.age == age ? this : new WitherExample(age, name);
}

protected WitherExample withName(@NonNull String name) {
  if (name == null) throw new java.lang.NullPointerException("name");
  return this.name == name ? this : new WitherExample(age, name);
}
}

View Code

==================================================================================

@Builder

【類級別，為你的類生成復雜的構建器API】

轉化前：

package com.sxd.entity;


import lombok.Builder;


@Builder
public class Order {
    private String orderId;
    private User user;
    private String productName;

}

View Code

編譯后：

package com.sxd.entity;

import java.beans.ConstructorProperties;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public static class OrderBuilder
  {
    private String orderId;
    private User user;
    private String productName;
    
    public String toString()
    {
      return "Order.OrderBuilder(orderId=" + this.orderId + ", user=" + this.user + ", productName=" + this.productName + ")";
    }
    
    public Order build()
    {
      return new Order(this.orderId, this.user, this.productName);
    }
    
    public OrderBuilder productName(String productName)
    {
      this.productName = productName;return this;
    }
    
    public OrderBuilder user(User user)
    {
      this.user = user;return this;
    }
    
    public OrderBuilder orderId(String orderId)
    {
      this.orderId = orderId;return this;
    }
  }
  
  public static OrderBuilder builder()
  {
    return new OrderBuilder();
  }
  
  @ConstructorProperties({"orderId", "user", "productName"})
  Order(String orderId, User user, String productName)
  {
    this.orderId = orderId;this.user = user;this.productName = productName;
  }
}

View Code

==============================================================

@Delegate

【屬性級別，同化所在屬性的類型的方法到本類中】

轉化前：【本屬性類型為String】

package com.sxd.entity;


import lombok.experimental.Delegate;


public class Order {
    private String orderId;
    private User user;
    @Delegate private String productName;

}

View Code

編譯后：

package com.sxd.entity;

import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.Locale;
import java.util.stream.IntStream;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  
  public IntStream codePoints()
  {
    return this.productName.codePoints();
  }
  
  public IntStream chars()
  {
    return this.productName.chars();
  }
  
  public String intern()
  {
    return this.productName.intern();
  }
  
  public char[] toCharArray()
  {
    return this.productName.toCharArray();
  }
  
  public String trim()
  {
    return this.productName.trim();
  }
  
  public String toUpperCase()
  {
    return this.productName.toUpperCase();
  }
  
  public String toUpperCase(Locale arg0)
  {
    return this.productName.toUpperCase(arg0);
  }
  
  public String toLowerCase()
  {
    return this.productName.toLowerCase();
  }
  
  public String toLowerCase(Locale arg0)
  {
    return this.productName.toLowerCase(arg0);
  }
  
  public String[] split(String arg0)
  {
    return this.productName.split(arg0);
  }
  
  public String[] split(String arg0, int arg1)
  {
    return this.productName.split(arg0, arg1);
  }
  
  public String replace(CharSequence arg0, CharSequence arg1)
  {
    return this.productName.replace(arg0, arg1);
  }
  
  public String replaceAll(String arg0, String arg1)
  {
    return this.productName.replaceAll(arg0, arg1);
  }
  
  public String replaceFirst(String arg0, String arg1)
  {
    return this.productName.replaceFirst(arg0, arg1);
  }
  
  public boolean contains(CharSequence arg0)
  {
    return this.productName.contains(arg0);
  }
  
  public boolean matches(String arg0)
  {
    return this.productName.matches(arg0);
  }
  
  public String replace(char arg0, char arg1)
  {
    return this.productName.replace(arg0, arg1);
  }
  
  public String concat(String arg0)
  {
    return this.productName.concat(arg0);
  }
  
  public CharSequence subSequence(int arg0, int arg1)
  {
    return this.productName.subSequence(arg0, arg1);
  }
  
  public String substring(int arg0, int arg1)
  {
    return this.productName.substring(arg0, arg1);
  }
  
  public String substring(int arg0)
  {
    return this.productName.substring(arg0);
  }
  
  public int lastIndexOf(String arg0, int arg1)
  {
    return this.productName.lastIndexOf(arg0, arg1);
  }
  
  public int lastIndexOf(String arg0)
  {
    return this.productName.lastIndexOf(arg0);
  }
  
  public int indexOf(String arg0, int arg1)
  {
    return this.productName.indexOf(arg0, arg1);
  }
  
  public int indexOf(String arg0)
  {
    return this.productName.indexOf(arg0);
  }
  
  public int lastIndexOf(int arg0, int arg1)
  {
    return this.productName.lastIndexOf(arg0, arg1);
  }
  
  public int lastIndexOf(int arg0)
  {
    return this.productName.lastIndexOf(arg0);
  }
  
  public int indexOf(int arg0, int arg1)
  {
    return this.productName.indexOf(arg0, arg1);
  }
  
  public int indexOf(int arg0)
  {
    return this.productName.indexOf(arg0);
  }
  
  public boolean endsWith(String arg0)
  {
    return this.productName.endsWith(arg0);
  }
  
  public boolean startsWith(String arg0)
  {
    return this.productName.startsWith(arg0);
  }
  
  public boolean startsWith(String arg0, int arg1)
  {
    return this.productName.startsWith(arg0, arg1);
  }
  
  public boolean regionMatches(boolean arg0, int arg1, String arg2, int arg3, int arg4)
  {
    return this.productName.regionMatches(arg0, arg1, arg2, arg3, arg4);
  }
  
  public boolean regionMatches(int arg0, String arg1, int arg2, int arg3)
  {
    return this.productName.regionMatches(arg0, arg1, arg2, arg3);
  }
  
  public int compareToIgnoreCase(String arg0)
  {
    return this.productName.compareToIgnoreCase(arg0);
  }
  
  public int compareTo(String arg0)
  {
    return this.productName.compareTo(arg0);
  }
  
  public boolean equalsIgnoreCase(String arg0)
  {
    return this.productName.equalsIgnoreCase(arg0);
  }
  
  public boolean contentEquals(CharSequence arg0)
  {
    return this.productName.contentEquals(arg0);
  }
  
  public boolean contentEquals(StringBuffer arg0)
  {
    return this.productName.contentEquals(arg0);
  }
  
  public byte[] getBytes()
  {
    return this.productName.getBytes();
  }
  
  public byte[] getBytes(Charset arg0)
  {
    return this.productName.getBytes(arg0);
  }
  
  public byte[] getBytes(String arg0)
    throws UnsupportedEncodingException
  {
    return this.productName.getBytes(arg0);
  }
  
  @Deprecated
  public void getBytes(int arg0, int arg1, byte[] arg2, int arg3)
  {
    this.productName.getBytes(arg0, arg1, arg2, arg3);
  }
  
  public void getChars(int arg0, int arg1, char[] arg2, int arg3)
  {
    this.productName.getChars(arg0, arg1, arg2, arg3);
  }
  
  public int offsetByCodePoints(int arg0, int arg1)
  {
    return this.productName.offsetByCodePoints(arg0, arg1);
  }
  
  public int codePointCount(int arg0, int arg1)
  {
    return this.productName.codePointCount(arg0, arg1);
  }
  
  public int codePointBefore(int arg0)
  {
    return this.productName.codePointBefore(arg0);
  }
  
  public int codePointAt(int arg0)
  {
    return this.productName.codePointAt(arg0);
  }
  
  public char charAt(int arg0)
  {
    return this.productName.charAt(arg0);
  }
  
  public boolean isEmpty()
  {
    return this.productName.isEmpty();
  }
  
  public int length()
  {
    return this.productName.length();
  }
}

View Code

==========================================================================

轉化前：【所在屬性類型為List】

package com.sxd.entity;


import lombok.experimental.Delegate;

import java.util.List;


public class Order {
    private String orderId;
    private User user;
    private String productName;
    @Delegate  private List<Integer> arrList;

}

View Code

編譯后：

package com.sxd.entity;

import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.Spliterator;
import java.util.function.UnaryOperator;

public class Order
{
  private String orderId;
  private User user;
  private String productName;
  private List<Integer> arrList;
  
  public Spliterator<Integer> spliterator()
  {
    return this.arrList.spliterator();
  }
  
  public List<Integer> subList(int arg0, int arg1)
  {
    return this.arrList.subList(arg0, arg1);
  }
  
  public ListIterator<Integer> listIterator(int arg0)
  {
    return this.arrList.listIterator(arg0);
  }
  
  public ListIterator<Integer> listIterator()
  {
    return this.arrList.listIterator();
  }
  
  public int lastIndexOf(Object arg0)
  {
    return this.arrList.lastIndexOf(arg0);
  }
  
  public int indexOf(Object arg0)
  {
    return this.arrList.indexOf(arg0);
  }
  
  public Integer remove(int arg0)
  {
    return (Integer)this.arrList.remove(arg0);
  }
  
  public void add(int arg0, Integer arg1)
  {
    this.arrList.add(arg0, arg1);
  }
  
  public Integer set(int arg0, Integer arg1)
  {
    return (Integer)this.arrList.set(arg0, arg1);
  }
  
  public Integer get(int arg0)
  {
    return (Integer)this.arrList.get(arg0);
  }
  
  public void clear()
  {
    this.arrList.clear();
  }
  
  public void sort(Comparator<? super Integer> arg0)
  {
    this.arrList.sort(arg0);
  }
  
  public void replaceAll(UnaryOperator<Integer> arg0)
  {
    this.arrList.replaceAll(arg0);
  }
  
  public boolean retainAll(Collection<?> arg0)
  {
    return this.arrList.retainAll(arg0);
  }
  
  public boolean removeAll(Collection<?> arg0)
  {
    return this.arrList.removeAll(arg0);
  }
  
  public boolean addAll(int arg0, Collection<? extends Integer> arg1)
  {
    return this.arrList.addAll(arg0, arg1);
  }
  
  public boolean addAll(Collection<? extends Integer> arg0)
  {
    return this.arrList.addAll(arg0);
  }
  
  public boolean containsAll(Collection<?> arg0)
  {
    return this.arrList.containsAll(arg0);
  }
  
  public boolean remove(Object arg0)
  {
    return this.arrList.remove(arg0);
  }
  
  public boolean add(Integer arg0)
  {
    return this.arrList.add(arg0);
  }
  
  public <T> T[] toArray(T[] arg0)
  {
    return this.arrList.toArray(arg0);
  }
  
  public Object[] toArray()
  {
    return this.arrList.toArray();
  }
  
  public Iterator<Integer> iterator()
  {
    return this.arrList.iterator();
  }
  
  public boolean contains(Object arg0)
  {
    return this.arrList.contains(arg0);
  }
  
  public boolean isEmpty()
  {
    return this.arrList.isEmpty();
  }
  
  public int size()
  {
    return this.arrList.size();
  }
}

View Code

============================================================================

@SneakyThrows

【異常處理注解，這里不做詳細解釋】

轉化前：

@SneakyThrows
public void testSneakyThrows() {
    throw new IllegalAccessException();
}

View Code

編譯后：

public void testSneakyThrows() {
    try {
        throw new IllegalAccessException();
    } catch (java.lang.Throwable $ex) {
        throw lombok.Lombok.sneakyThrow($ex);
    }
}

View Code

============================================================================

@_({注解1，注解2})或@_(注解) 配合onMethod=使用

【屬性級別，用於將注解放在注解中使用】

轉化前：

package com.sxd.entity;

import lombok.Getter;
import lombok.Setter;

import javax.persistence.Column;
import javax.persistence.Id;

public class Order {

    @Getter(onMethod = @_({@Column,@Id}))
    @Setter
    private String id;
}

View Code

編譯后：

package com.sxd.entity;

import javax.persistence.Column;
import javax.persistence.Id;

public class Order
{
  private String id;
  
  @Column
  @Id
  public String getId()
  {
    return this.id;
  }
  
  public void setId(String id)
  {
    this.id = id;
  }
}

View Code

【注意：這個時而有用，時而報錯，具體問題依舊找不到~~~~~~~~~~~~具體看附錄2】

============================================================================================================

最后，如果使用了lombok的話，如何在實體類上聲明實體對數據表的映射？

注意：@Column等注解是可以直接放在字段上而不用放在get方法上

例如：創建不同包下同名的實體類User.java

自己寫get/set方法的User類如下：

package com.sxd.entity;



import org.hibernate.annotations.GenericGenerator;

import javax.persistence.*;

@Entity
@GenericGenerator(name = "uuid2", strategy = "org.hibernate.id.UUIDGenerator" )
public class User {
    private String id;
    private String username;
    private String password;
    private Integer age;

    @Id
    @GeneratedValue(generator = "uuid2")
    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    @Column(nullable = false)
    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    @Column(nullable = false)
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Column(nullable = false)
    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public User() {

    }

    public User(String id, String username, String password, Integer age) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" +
                "id='" + id + '\'' +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", age=" + age +
                '}';
    }
}

View Code

編譯完是：

package com.sxd.entity;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import org.hibernate.annotations.GenericGenerator;

@Entity
@GenericGenerator(name="uuid2", strategy="org.hibernate.id.UUIDGenerator")
public class User
{
  private String id;
  private String username;
  private String password;
  private Integer age;
  
  @Id
  @GeneratedValue(generator="uuid2")
  public String getId()
  {
    return this.id;
  }
  
  public void setId(String id)
  {
    this.id = id;
  }
  
  @Column(nullable=false)
  public String getUsername()
  {
    return this.username;
  }
  
  public void setUsername(String username)
  {
    this.username = username;
  }
  
  @Column(nullable=false)
  public String getPassword()
  {
    return this.password;
  }
  
  public void setPassword(String password)
  {
    this.password = password;
  }
  
  @Column(nullable=false)
  public Integer getAge()
  {
    return this.age;
  }
  
  public void setAge(Integer age)
  {
    this.age = age;
  }
  
  public User() {}
  
  public User(String id, String username, String password, Integer age)
  {
    this.id = id;
    this.username = username;
    this.password = password;
    this.age = age;
  }
  
  public String toString()
  {
    return "User{id='" + this.id + '\'' + ", username='" + this.username + '\'' + ", password='" + this.password + '\'' + ", age=" + this.age + '}';
  }
}

View Code

===================　　　　　　　　　　　　　　　　　　　　　==================================

使用lombok之后如下：

package com.sxd.controller;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.experimental.Accessors;
import org.hibernate.annotations.GenericGenerator;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
@GenericGenerator(name = "uuid2", strategy = "org.hibernate.id.UUIDGenerator" )
@Data(staticConstructor = "of")
@NoArgsConstructor
@AllArgsConstructor
@Accessors(chain = true)
public class User {
    @Id
    @GeneratedValue(generator = "uuid2")private String id;
    private String username;

    @Column(nullable = false)
    private String password;

    @Column(nullable = false)
    private Integer age;


}

View Code

編譯完是：

package com.sxd.controller;

import java.beans.ConstructorProperties;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import org.hibernate.annotations.GenericGenerator;

@Entity
@GenericGenerator(name="uuid2", strategy="org.hibernate.id.UUIDGenerator")
public class User
{
  @Id
  @GeneratedValue(generator="uuid2")
  private String id;
  private String username;
  @Column(nullable=false)
  private String password;
  @Column(nullable=false)
  private Integer age;
  
  public User setAge(Integer age)
  {
    this.age = age;return this;
  }
  
  public String toString()
  {
    return "User(id=" + getId() + ", username=" + getUsername() + ", password=" + getPassword() + ", age=" + getAge() + ")";
  }
  
  public int hashCode()
  {
    int PRIME = 59;int result = 1;Object $id = getId();result = result * 59 + ($id == null ? 43 : $id.hashCode());Object $username = getUsername();result = result * 59 + ($username == null ? 43 : $username.hashCode());Object $password = getPassword();result = result * 59 + ($password == null ? 43 : $password.hashCode());Object $age = getAge();result = result * 59 + ($age == null ? 43 : $age.hashCode());return result;
  }
  
  protected boolean canEqual(Object other)
  {
    return other instanceof User;
  }
  
  public User setId(String id)
  {
    this.id = id;return this;
  }
  
  public User setUsername(String username)
  {
    this.username = username;return this;
  }
  
  public User setPassword(String password)
  {
    this.password = password;return this;
  }
  
  public boolean equals(Object o)
  {
    if (o == this) {
      return true;
    }
    if (!(o instanceof User)) {
      return false;
    }
    User other = (User)o;
    if (!other.canEqual(this)) {
      return false;
    }
    Object this$id = getId();Object other$id = other.getId();
    if (this$id == null ? other$id != null : !this$id.equals(other$id)) {
      return false;
    }
    Object this$username = getUsername();Object other$username = other.getUsername();
    if (this$username == null ? other$username != null : !this$username.equals(other$username)) {
      return false;
    }
    Object this$password = getPassword();Object other$password = other.getPassword();
    if (this$password == null ? other$password != null : !this$password.equals(other$password)) {
      return false;
    }
    Object this$age = getAge();Object other$age = other.getAge();return this$age == null ? other$age == null : this$age.equals(other$age);
  }
  
  @ConstructorProperties({"id", "username", "password", "age"})
  public User(String id, String username, String password, Integer age)
  {
    this.id = id;this.username = username;this.password = password;this.age = age;
  }
  
  public String getId()
  {
    return this.id;
  }
  
  public String getUsername()
  {
    return this.username;
  }
  
  public String getPassword()
  {
    return this.password;
  }
  
  public Integer getAge()
  {
    return this.age;
  }
  
  public User() {}
}

View Code

有一個疑問，映射注解放在屬性上和放在get方法上有什么區別？？？【看附錄3】

===============================================================附錄1：equals()方法和hashCode()方法的意義==========================================================

摘錄：

1.hashcode是用來查找的，如果你學過數據結構就應該知道，在查找和排序這一章有  
例如內存中有這樣的位置  
0  1  2  3  4  5  6  7    
而我有個類，這個類有個字段叫ID,我要把這個類存放在以上8個位置之一，如果不用hashcode而任意存放，那么當查找時就需要到這八個位置里挨個去找，或者用二分法一類的算法。  
但如果用hashcode那就會使效率提高很多。  
我們這個類中有個字段叫ID,那么我們就定義我們的hashcode為ID％8，然后把我們的類存放在取得得余數那個位置。比如我們的ID為9，9除8的余數為1，那么我們就把該類存在1這個位置，如果ID是13，求得的余數是5，那么我們就把該類放在5這個位置。這樣，以后在查找該類時就可以通過ID除 8求余數直接找到存放的位置了。  
  
2.但是如果兩個類有相同的hashcode怎么辦那（我們假設上面的類的ID不是唯一的），例如9除以8和17除以8的余數都是1，那么這是不是合法的，
回答是：可以這樣。那么如何判斷呢？在這個時候就需要定義 equals了。  
也就是說，我們先通過 hashcode來判斷兩個類是否存放某個桶里，但這個桶里可能有很多類，那么我們就需要再通過 equals 來在這個桶里找到我們要的類。  
那么。重寫了equals()，為什么還要重寫hashCode()呢？  
想想，你要在一個桶里找東西，你必須先要找到這個桶啊，你不通過重寫hashcode()來找到桶，光重寫equals()有什么用啊

==============================================================附錄2：@Getter()等lombok注解配合hibernate的映射注解怎么使用===========================================================

如果在項目中真的使用lombok的注解的話，映射注解應該如何處理呢？

寥寥無幾的資料中有大概類似於如下的寫法：

　　@Getter(onMethod = @_({@Id,@Column(name="id",nullable=false),@GeneratedValue(strategy= GenerationType.AUTO)}))
    @Setter
    private Integer id;

親自試了一下，

如下：

報錯如下：

其實在@Getter()注解接口中定義如下：

但是具體怎么去寫，還沒有研究出來。

【如有解決方法，不吝賜教！！】

所以，最終按照並列將注解寫在屬性上，而不是在@Getter（）注解中寫@Column（）注解。

如下：

@Data(staticConstructor = "of")
@NoArgsConstructor
@AllArgsConstructor
@Accessors(chain = true)
@Entity
@GenericGenerator(name = "uuid2", strategy = "org.hibernate.id.UUIDGenerator" )
public class Member {


    @Id
    @GeneratedValue(generator = "uuid2")
    @Column(name = "memberId")
    private String memberId;

    @OneToOne(cascade = {CascadeType.MERGE,CascadeType.REFRESH},fetch = FetchType.EAGER)
    private User user;

    @Column(name="memberGrade",nullable = false)
    @NonNull
    private Integer memberGrade;
}

View Code

編譯完成如下：

package com.sxd.entity;

import java.beans.ConstructorProperties;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import lombok.NonNull;
import org.hibernate.annotations.GenericGenerator;

@Entity
@GenericGenerator(name="uuid2", strategy="org.hibernate.id.UUIDGenerator")
public class Member
{
  @Id
  @GeneratedValue(generator="uuid2")
  @Column(name="memberId")
  private String memberId;
  @OneToOne(cascade={javax.persistence.CascadeType.MERGE, javax.persistence.CascadeType.REFRESH}, fetch=FetchType.EAGER)
  private User user;
  @Column(name="memberGrade", nullable=false)
  @NonNull
  private Integer memberGrade;
  
  public String toString()
  {
    return "Member(memberId=" + getMemberId() + ", user=" + getUser() + ", memberGrade=" + getMemberGrade() + ")";
  }
  
  public int hashCode()
  {
    int PRIME = 59;int result = 1;Object $memberId = getMemberId();result = result * 59 + ($memberId == null ? 43 : $memberId.hashCode());Object $user = getUser();result = result * 59 + ($user == null ? 43 : $user.hashCode());Object $memberGrade = getMemberGrade();result = result * 59 + ($memberGrade == null ? 43 : $memberGrade.hashCode());return result;
  }
  
  public Member setMemberId(String memberId)
  {
    this.memberId = memberId;return this;
  }
  
  public Member setUser(User user)
  {
    this.user = user;return this;
  }
  
  public Member setMemberGrade(@NonNull Integer memberGrade)
  {
    if (memberGrade == null) {
      throw new NullPointerException("memberGrade");
    }
    this.memberGrade = memberGrade;return this;
  }
  
  protected boolean canEqual(Object other)
  {
    return other instanceof Member;
  }
  
  public boolean equals(Object o)
  {
    if (o == this) {
      return true;
    }
    if (!(o instanceof Member)) {
      return false;
    }
    Member other = (Member)o;
    if (!other.canEqual(this)) {
      return false;
    }
    Object this$memberId = getMemberId();Object other$memberId = other.getMemberId();
    if (this$memberId == null ? other$memberId != null : !this$memberId.equals(other$memberId)) {
      return false;
    }
    Object this$user = getUser();Object other$user = other.getUser();
    if (this$user == null ? other$user != null : !this$user.equals(other$user)) {
      return false;
    }
    Object this$memberGrade = getMemberGrade();Object other$memberGrade = other.getMemberGrade();return this$memberGrade == null ? other$memberGrade == null : this$memberGrade.equals(other$memberGrade);
  }
  
  @ConstructorProperties({"memberId", "user", "memberGrade"})
  public Member(String memberId, User user, @NonNull Integer memberGrade)
  {
    if (memberGrade == null) {
      throw new NullPointerException("memberGrade");
    }
    this.memberId = memberId;this.user = user;this.memberGrade = memberGrade;
  }
  
  public String getMemberId()
  {
    return this.memberId;
  }
  
  public User getUser()
  {
    return this.user;
  }
  
  @NonNull
  public Integer getMemberGrade()
  {
    return this.memberGrade;
  }
  
  public Member() {}
}

View Code

那么最后看附錄3，了解最后一個問題，映射注解放在屬性上和放在get方法上有什么區別？

=======================================================================附錄3：映射注解放在屬性上和放在get()方法上有什么區別======================================================================

摘錄自：http://blog.csdn.net/most_rabbitfishes/article/details/70904949

對於屬性字段和表的字段關系對應的注解屬性的位置，一般我們采用以下兩種方式:

第一種：

是把注解@Column(name ="xx")放在field上，一種是把注解放在get方法上一般放在field上看起來比較集中、清晰；

第二種：

是把注解@Column(name= "xx")放在get方法上，這種方式看起來比較散漫、不很清楚；

但是第一種方式這樣做實際上破壞了java面向對象的封裝性，原因是一般我們寫javaBean，成員變量通常定義為private，目的就是不讓別人來直接訪問的私有屬性，而我們把注解放在私有成員的變量上，就是默認hibernate可以直接訪問我們的私有的成員變量，所以我們定義屬性為private，就實際沒有多大意義，至於hibernate為什么能訪問，hibernate采用java的反射機制完全可以訪問私有成員變量！所以應該放在get方法上，第二種方式這個時候就顯得更加合理。

隨即，我采用了附錄2中實體用於hibernate自動生成數據表的表結構：

Hibernate自動幫我們建表:

如果我們采用注解的方式在我們的實體Bean上，又想通過掃描這些注解的Bean，通過Hibernate自動幫我們建表，那么你就會發現字段注解的位置不同甚至會影響到建表的結構，尤其是大字段、外鍵約束的生成效果。

如果采用第一種方式注解到私有字段上，這種幫我們建立表結構、約束條件和大字段Lob類型這些都是非常正常的，而通過第二種方式注解到get方法上，這種幫我們的建立的表大部分正常字段正常，而外鍵關聯的和大字段就會出現問題.

雖然項目的開發我們不采用hibernate幫我們自動建表，通常我們還是要手動的建表，所以這一些是對於通過Hibernate幫我們自動建表要考慮的！而實際開發中，已注解在get方法上為多數！

結論：如上將注解建立在屬性上，生成的表結構，約束條件，外鍵等都正常，所以，如果你要使用hibernate的生成策略，在你建立好實體之后自動去建立數據表的話，同時使用lombok的注解和映射注解都放在屬性上是合適的！！！

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