Mybatis Generator使用
介紹
使用MyBatis Generator (MBG) 可以減少重復代碼工作量，自動根據數據庫表的結構生成MyBatis的Model/Dao/XML。
本文主要介紹MBG如何根據Oralce數據庫表的結構生成相應文件的。同時通過MBG提供的插件擴展能力，實現兩個插件，用於在生成的Model中包含數據庫中定義的注釋和添加Lombok注解。
項目結構
本演示項目使用IDE為IDEA。首先創建一個簡單的Maven工程。
根據《IntelliJ IDEA 創建 Maven簡單項目》創建Maven工程。
項目結構預覽：
下面是使用MBG生成MyBatis中的Model(Pojo)/Dao/XML各層的最終項目結構。
com.zqq.dao 存放生成的MyBatis數據庫操作類
com.zqq.pojo 存放與數據庫表映射的數據庫模型bean
mappers/DemoPojoMapper.xml 存放與DAO包中的方法對應的sql操作語句文件
配置文件（搭建Maven項目）
使用MBG不需要依賴於Spring等框架，只需要依賴基本的MBG插件即可。但是由於是根據數據庫表生成MyBatis操作對象，因此還需要配置數據庫連接信息datasource.properties。同時，使用MBG時需要配置generatorConfig.xml文件。
注意oracle驅動與jdk的關系 ojdbc7 對應jdk 7 8 https://download.csdn.net/download/panhaigang123/10757085
//datasource.properties
#下面配置的是Oracle數據庫的連接信息，oracle url要使用域名：端口/實例
#驅動本地路徑
db.driverLocation=D:\\code\\private\\model_generator\\src\\main\\tools\\ojdbc7-12.1.0.2.jar
#驅動類路徑
db.driverClassName=oracle.jdbc.driver.OracleDriver
#數據庫連接信息
db.url=jdbc:oracle:thin:@host:1521/database
db.username=xxx
db.password=xxx
//generatorConfig.xml
<!--配置文件中的suppresscomment不要配置。type=MyCommentGenerator 要用全類名，否則可能找不到。多次執行generate，生成的xml只能追加無法覆蓋問題，使用插件解決-->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
"http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
<!--導入屬性配置-->
<properties resource="datasource.properties"></properties>
<!--指定特定數據庫的jdbc驅動jar包的位置-->
<classPathEntry location="${db.driverLocation}"/>
<context id="default" targetRuntime="MyBatis3">
<!--可選配置，使用自定義插件，通過注解使每次重復執行時覆蓋原有的xml文件-->
<!--<plugin type="OverIsMergeablePlugin"/>-->
<!--可選配置，使用自定義插件，生成Lombok注解-->
<plugin type="com.zqq.plugins.LombokPlugin">
<property name="hasLombok" value="true"/>
</plugin>
<!-- 可選配置，旨在創建class時，對注釋進行控制 -->
<!--MyCommentGenerator實現了對字段添加注釋功能-->
<commentGenerator type="com.zqq.plugins.MyCommentGenerator">
<!--<property name="suppressDate" value="true"/>-->
<!--不能添加如下配置，否則無法生成注釋-->
<!--<property name="suppressAllComments" value="true"/>-->
</commentGenerator>
<!--jdbc的數據庫連接 -->
<jdbcConnection
driverClass="${db.driverClassName}"
connectionURL="${db.url}"
userId="${db.username}"
password="${db.password}">
<property name="remarksReporting" value="true"></property>
</jdbcConnection>
<!-- 非必需，類型處理器，在數據庫類型和java類型之間的轉換控制-->
<javaTypeResolver>
<property name="forceBigDecimals" value="false"/>
</javaTypeResolver>
<!-- Model模型生成器,用來生成含有主鍵key的類，記錄類 以及查詢Example類
targetPackage 指定生成的model生成所在的包名
targetProject 指定在該項目下所在的路徑
-->
<javaModelGenerator targetPackage="com.zqq.pojo" targetProject="./src/main/java">
<!-- 是否允許子包，即targetPackage.schemaName.tableName -->
<property name="enableSubPackages" value="false"/>
<!-- 是否對model添加 構造函數 當immutable為false時，此處設置才有效-->
<property name="constructorBased" value="false"/>
<!-- 是否對類CHAR類型的列的數據進行trim操作 -->
<property name="trimStrings" value="true"/>
<!-- 建立的Model對象是否 不可改變 即生成的Model對象不會有 setter方法，只有構造方法 -->
<!--該屬性用來配置實體類屬性是否可變，如果設置為true，那么constructorBased不管設置成什么，都會使用構造方法入參，並且不會生成setter方法。如果為false，實體類屬性就可以改變。默認為false。-->
<property name="immutable" value="false"/>
</javaModelGenerator>
<!--mapper映射文件生成所在的目錄 為每一個數據庫的表生成對應的SqlMap文件 -->
<sqlMapGenerator targetPackage="mappers" targetProject="./src/main/resources">
<property name="enableSubPackages" value="false"/>
</sqlMapGenerator>
<!-- 客戶端代碼，生成易於使用的針對Model對象和XML配置文件 的代碼
type="ANNOTATEDMAPPER",生成Java Model 和基於注解的Mapper對象
type="MIXEDMAPPER",生成基於注解的Java Model 和相應的Mapper對象
type="XMLMAPPER",生成SQLMap XML文件和獨立的Mapper接口
-->
<!-- targetPackage：mapper接口dao生成的位置 -->
<javaClientGenerator type="XMLMAPPER" targetPackage="com.zqq.dao" targetProject="./src/main/java">
<!-- enableSubPackages:是否讓schema作為包的后綴 -->
<property name="enableSubPackages" value="false"/>
</javaClientGenerator>
<!--需要生成相應MyBatis操作dao/pojo/xml的數據庫表以及映射的pojo-->
<table tableName="DEMO_TABLE" domainObjectName="DemoPojo"
enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false"
enableSelectByExample="false" selectByExampleQueryId="false"></table>
</context>
</generatorConfiguration>
POM配置
下面給出pom.xml的配置。MBG要用1.3.3及以后版本 否則無法生成類注釋addModelClassComment。
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com</groupId>
<artifactId>MBG</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>MBG DEMO</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
<groupId>org.mybatis.generator</groupId>
<artifactId>mybatis-generator-core</artifactId>
<version>1.3.5</version>
</dependency>
</dependencies>
<build>
<finalName>mmall</finalName>
<plugins>
<plugin>
<groupId>org.mybatis.generator</groupId>
<artifactId>mybatis-generator-maven-plugin</artifactId>
<version>1.3.5</version>
<configuration>
<verbose>true</verbose>
<overwrite>true</overwrite>
</configuration>
</plugin>
</plugins>
</build>
</project>
自定義插件
MBG提供的插件的擴展類PluginAdapter，可以實現自己需要的特定功能。需要注意的是，MBG不同的版本提供的接口是不同的。下面分別給出，三個自定義插件的實現。
LombokPlugin
該插件提供了在生成的POJO上面添加Lombok注解。
package com.zqq.plugins;
import org.mybatis.generator.api.IntrospectedColumn;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.PluginAdapter;
import org.mybatis.generator.api.dom.java.Interface;
import org.mybatis.generator.api.dom.java.Method;
import org.mybatis.generator.api.dom.java.TopLevelClass;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
public class LombokPlugin extends PluginAdapter
{
@Override
public boolean validate(List<String> list)
{
return true;
}
@Override
public boolean modelBaseRecordClassGenerated(TopLevelClass topLevelClass, IntrospectedTable introspectedTable)
{
//添加domain的import
topLevelClass.addImportedType("lombok.Data");
topLevelClass.addImportedType("lombok.Builder");
topLevelClass.addImportedType("lombok.NoArgsConstructor");
topLevelClass.addImportedType("lombok.AllArgsConstructor");
//添加domain的注解
topLevelClass.addAnnotation("@Data");
topLevelClass.addAnnotation("@Builder");
topLevelClass.addAnnotation("@NoArgsConstructor");
topLevelClass.addAnnotation("@AllArgsConstructor");
return true;
}
@Override
public boolean modelSetterMethodGenerated(Method method, TopLevelClass topLevelClass, IntrospectedColumn introspectedColumn, IntrospectedTable introspectedTable, ModelClassType modelClassType)
{
//不生成getter
return false;
}
@Override
public boolean modelGetterMethodGenerated(Method method, TopLevelClass topLevelClass, IntrospectedColumn introspectedColumn, IntrospectedTable introspectedTable, ModelClassType modelClassType)
{
//不生成setter
return false;
}
private String date2Str(Date date)
{
SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
return sdf.format(date);
}
}
MyCommentGenerator
原生的MBG無法將數據庫中的表注釋及字段注釋添加到生成的POJO的類或字段上。該插件可以提供該能力生成Oracle或MySQL數據庫表及字段的注釋。
package com.zqq.plugins;
import static org.mybatis.generator.internal.util.StringUtility.isTrue;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Properties;
import java.util.Set;
import org.mybatis.generator.api.CommentGenerator;
import org.mybatis.generator.api.IntrospectedColumn;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.dom.java.*;
import org.mybatis.generator.api.dom.xml.XmlElement;
import org.mybatis.generator.config.MergeConstants;
import org.mybatis.generator.config.PropertyRegistry;
import org.mybatis.generator.internal.util.StringUtility;
public class MyCommentGenerator implements CommentGenerator
{
private Properties properties;
private Properties systemPro;
private boolean suppressDate;
private boolean suppressAllComments;
private String currentDateStr;
public MyCommentGenerator()
{
super();
properties = new Properties();
systemPro = System.getProperties();
suppressDate = false;
suppressAllComments = false;
currentDateStr = (new SimpleDateFormat("yyyy-MM-dd")).format(new Date());
}
@Override
public void addJavaFileComment(CompilationUnit compilationUnit)
{
// add no file level comments by default
return;
}
/**
* Adds a suitable comment to warn users that the element was generated, and
* when it was generated.
*/
@Override
public void addComment(XmlElement xmlElement)
{
return;
}
@Override
public void addRootComment(XmlElement rootElement)
{
// add no document level comments by default
return;
}
@Override
public void addConfigurationProperties(Properties properties)
{
this.properties.putAll(properties);
suppressDate = isTrue(properties.getProperty(PropertyRegistry.COMMENT_GENERATOR_SUPPRESS_DATE));
suppressAllComments = isTrue(properties.getProperty(PropertyRegistry.COMMENT_GENERATOR_SUPPRESS_ALL_COMMENTS));
}
/**
* This method adds the custom javadoc tag for. You may do nothing if you do
* not wish to include the Javadoc tag - however, if you do not include the
* Javadoc tag then the Java merge capability of the eclipse plugin will
* break.
*
* @param javaElement the java element
*/
protected void addJavadocTag(JavaElement javaElement, boolean markAsDoNotDelete)
{
javaElement.addJavaDocLine(" *");
StringBuilder sb = new StringBuilder();
sb.append(" * ");
sb.append(MergeConstants.NEW_ELEMENT_TAG);
if (markAsDoNotDelete)
{
sb.append(" do_not_delete_during_merge");
}
String s = getDateString();
if (s != null)
{
sb.append(' ');
sb.append(s);
}
javaElement.addJavaDocLine(sb.toString());
}
/**
* This method returns a formated date string to include in the Javadoc tag
* and XML comments. You may return null if you do not want the date in
* these documentation elements.
*
* @return a string representing the current timestamp, or null
*/
protected String getDateString()
{
String result = null;
if (!suppressDate)
{
result = currentDateStr;
}
return result;
}
@Override
public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable)
{
if (suppressAllComments)
{
return;
}
StringBuilder sb = new StringBuilder();
innerClass.addJavaDocLine("/**");
sb.append(" * ");
sb.append(introspectedTable.getFullyQualifiedTable());
sb.append(" ");
sb.append(getDateString());
innerClass.addJavaDocLine(sb.toString());
innerClass.addJavaDocLine(" */");
}
@Override
public void addEnumComment(InnerEnum innerEnum, IntrospectedTable introspectedTable)
{
if (suppressAllComments)
{
return;
}
StringBuilder sb = new StringBuilder();
innerEnum.addJavaDocLine("/**");
// addJavadocTag(innerEnum, false);
sb.append(" * ");
sb.append(introspectedTable.getFullyQualifiedTable());
innerEnum.addJavaDocLine(sb.toString());
innerEnum.addJavaDocLine(" */");
}
/**
* 添加字段注釋
*
* @param field
* @param introspectedTable
* @return
* @throws
* @auther
* @since 11:58 2019/1/9
*/
@Override
public void addFieldComment(Field field, IntrospectedTable introspectedTable)
{
if (suppressAllComments)
{
return;
}
StringBuilder sb = new StringBuilder();
field.addJavaDocLine("/**");
sb.append(" * ");
sb.append(introspectedTable.getFullyQualifiedTable());
field.addJavaDocLine(sb.toString());
field.addJavaDocLine(" */");
}
//字段添加ApiModelProperty
@Override
public void addFieldComment(Field field, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn)
{
if (suppressAllComments)
{
return;
}
StringBuilder sb = new StringBuilder();
field.addJavaDocLine("/**");
sb.append(" * ");
sb.append(introspectedColumn.getRemarks());
field.addJavaDocLine(sb.toString());
// addJavadocTag(field, false);
field.addJavaDocLine(" */");
StringBuilder sb1 = new StringBuilder();
//@ApiModelProperty(name = "approveStatus", notes = "審批狀態")
sb1.append("@ApiModelProperty").append("(name = \"").append(field.getName())
.append("\" , notes = \"").append(introspectedColumn.getRemarks())
.append("\")");
System.out.println(sb1.toString());
field.addJavaDocLine(sb1.toString());
}
@Override
public void addGeneralMethodComment(Method method, IntrospectedTable introspectedTable)
{
if (suppressAllComments)
{
return;
}
// method.addJavaDocLine("/**");
// addJavadocTag(method, false);
// method.addJavaDocLine(" */");
}
@Override
public void addGetterComment(Method method, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn)
{
if (suppressAllComments)
{
return;
}
method.addJavaDocLine("/**");
StringBuilder sb = new StringBuilder();
sb.append(" * ");
sb.append(introspectedColumn.getRemarks());
method.addJavaDocLine(sb.toString());
sb.setLength(0);
sb.append(" * @return ");
sb.append(introspectedColumn.getActualColumnName());
sb.append(" ");
sb.append(introspectedColumn.getRemarks());
method.addJavaDocLine(sb.toString());
// addJavadocTag(method, false);
method.addJavaDocLine(" */");
}
@Override
public void addSetterComment(Method method, IntrospectedTable introspectedTable, IntrospectedColumn introspectedColumn)
{
if (suppressAllComments)
{
return;
}
method.addJavaDocLine("/**");
StringBuilder sb = new StringBuilder();
sb.append(" * ");
sb.append(introspectedColumn.getRemarks());
method.addJavaDocLine(sb.toString());
Parameter parm = method.getParameters().get(0);
sb.setLength(0);
sb.append(" * @param ");
sb.append(parm.getName());
sb.append(" ");
sb.append(introspectedColumn.getRemarks());
method.addJavaDocLine(sb.toString());
// addJavadocTag(method, false);
method.addJavaDocLine(" */");
}
/**
* 內部類的注釋
*
* @param innerClass
* @param introspectedTable
* @param markAsDoNotDelete
* @return
* @throws
* @auther
* @since 11:59 2019/1/9
*/
@Override
public void addClassComment(InnerClass innerClass, IntrospectedTable introspectedTable, boolean markAsDoNotDelete)
{
if (suppressAllComments)
{
return;
}
StringBuilder sb = new StringBuilder();
innerClass.addJavaDocLine("/**");
sb.append(" * ");
sb.append(introspectedTable.getFullyQualifiedTable());
innerClass.addJavaDocLine(sb.toString());
sb.setLength(0);
sb.append(" * @author ");
sb.append(systemPro.getProperty("user.name"));
sb.append(" ");
sb.append(currentDateStr);
// addJavadocTag(innerClass, markAsDoNotDelete);
innerClass.addJavaDocLine(" */");
}
/**
* 獲取表注釋，設置到Bean注釋
*
* @param topLevelClass
* @param introspectedTable
* @return
* @throws
* @auther
* @since 11:57 2019/1/9
*/
@Override
public void addModelClassComment(TopLevelClass topLevelClass, IntrospectedTable introspectedTable)
{
topLevelClass.addJavaDocLine("/**");
String remarks = introspectedTable.getRemarks();
if (StringUtility.stringHasValue(remarks))
{
String[] remarkLines = remarks.split(System.getProperty("line.separator"));
for (String remarkLine : remarkLines)
{
topLevelClass.addJavaDocLine(" * " + remarkLine);
}
}
// topLevelClass.addJavaDocLine(" * ");
StringBuilder sb = new StringBuilder();
sb.append(" * ");
sb.append(introspectedTable.getFullyQualifiedTable());
topLevelClass.addJavaDocLine(sb.toString());
// topLevelClass.addJavaDocLine(" *");
// addJavadocTag(topLevelClass, false);
topLevelClass.addJavaDocLine(" */");
}
}
OverIsMergeablePlugin
該插件用於解決多次執行generate，生成的xml只能追加無法覆蓋問題。一般情況下不需要多次執行generate操作。
package com.zqq.plugins;
import org.mybatis.generator.api.GeneratedXmlFile;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.PluginAdapter;
import java.lang.reflect.Field;
import java.util.List;
/**
* 解決生成xml無法覆蓋只能追加的問題
*
* @author
* @version v1.0
* @since 13:42 2019/1/9
*/
public class OverIsMergeablePlugin extends PluginAdapter
{
@Override
public boolean validate(List<String> warnings)
{
return true;
}
@Override
public boolean sqlMapGenerated(GeneratedXmlFile sqlMap, IntrospectedTable introspectedTable)
{
try
{
Field field = sqlMap.getClass().getDeclaredField("isMergeable");
field.setAccessible(true);
field.setBoolean(sqlMap, false);
} catch (Exception e)
{
e.printStackTrace();
}
return true;
}
}
生成
MBG啟動可以直接通過mybatis-generator:generate命令執行，也可以直接通過main方法執行。下面給出main方法執行的方式。
package com.zqq;
import org.mybatis.generator.api.MyBatisGenerator;
import org.mybatis.generator.config.Configuration;
import org.mybatis.generator.config.xml.ConfigurationParser;
import org.mybatis.generator.exception.InvalidConfigurationException;
import org.mybatis.generator.exception.XMLParserException;
import org.mybatis.generator.internal.DefaultShellCallback;
import java.io.File;
import java.io.IOException;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class App
{
public static void main(String[] args)
{
List<String> warnings = new ArrayList<String>();
try
{
// true:生成的文件覆蓋之前的
boolean overwrite = true;
// 讀取配置,構造 Configuration 對象.
// 如果不想使用配置文件的話,也可以直接來 new Configuration(),然后給相應屬性賦值.
File configFile = new File("./src/main/resources/generatorConfig.xml");
ConfigurationParser cp = new ConfigurationParser(warnings);
// Configuration config = cp.parseConfiguration(App.class.getClassLoader().getResourceAsStream("generatorConfig.xml"));
Configuration config = cp.parseConfiguration(configFile);
DefaultShellCallback callback = new DefaultShellCallback(overwrite);
MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
myBatisGenerator.generate(null);
} catch (SQLException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
} catch (InterruptedException e)
{
e.printStackTrace();
} catch (InvalidConfigurationException e)
{
e.printStackTrace();
} catch (XMLParserException e)
{
e.printStackTrace();
}
}
}