前言：如果你是初學者，請完全按照我的教程以及代碼來搭建（文末會附上完整的項目代碼包，你可以直接下載我提供的完整項目代碼包然后自行體驗！），為了照顧初學者所以貼圖比較多，請耐心跟着教程來，希望這個項目Demo能給你一些幫助，如果覺得寫的還可以請給個關注和推薦，謝謝！
題外話：剛開始學着用markdown來寫博文，格式不好的地方請見諒
一、pom.xml和application.yml
1、pom.xml中添加相關依賴，這里我把我的pom.xml代碼貼出來
<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.4.3</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>study</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>study</name>
<description>Demo project for Spring Boot</description>
<properties>
<!--依賴的版本-->
<java.version>1.8</java.version>
<mysql.version>8.0.13</mysql.version>
<mybatisPlus.version>3.4.1</mybatisPlus.version>
<druid.version>1.0.9</druid.version>
<swagger.version>2.9.2</swagger.version>
<hutool.version>5.5.8</hutool.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!--mysql-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
<version>${mysql.version}</version>
</dependency>
<!-- MyBatis-Plus-->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>${mybatisPlus.version}</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-generator</artifactId>
<version>${mybatisPlus.version}</version>
</dependency>
<!--druid-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>${druid.version}</version>
</dependency>
<!--swagger2-->
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
<version>${swagger.version}</version>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger-ui</artifactId>
<version>${swagger.version}</version>
</dependency>
<!--hutool-->
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-all</artifactId>
<version>${hutool.version}</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<excludes>
<exclude>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</exclude>
</excludes>
</configuration>
</plugin>
</plugins>
</build>
2、在resources下新建application.yml文件，並添加如下配置
# 配置端口
server:
port: 8080
#----------------druid數據源配置-----------------------
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
druid:
#這里跟pom里面mysql-connector版本相關8.0之后用com.mysql.cj.jdbc.Driver，之前用com.mysql.jdbc.Driver
driver-class-name: com.mysql.cj.jdbc.Driver
#這里改成你自己的數據庫名稱以及賬號和密碼
url: jdbc:mysql://127.0.0.1:3306/study?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowPublicKeyRetrieval=true
username: root
password: 123456
initialSize: 10
minIdle: 10
maxActive: 30
# 配置獲取連接等待超時的時間
maxWait: 60000
# 配置間隔多久才進行一次檢測，檢測需要關閉的空閑連接，單位是毫秒
timeBetweenEvictionRunsMillis: 60000
# 配置一個連接在池中最小生存的時間，單位是毫秒
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 1 FROM DUAL
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
# 打開PSCache，並且指定每個連接上PSCache的大小
poolPreparedStatements: true
# 配置監控統計攔截的filters，去掉后監控界面sql無法統計，'wall'用於防火牆
#filters: stat,wall,log4j
# 通過connectProperties屬性來打開mergeSql功能；慢SQL記錄
connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
# 合並多個DruidDataSource的監控數據
useGlobalDataSourceStat: true
#----------------mybatis plus配置-----------------------
mybatis-plus:
# xml掃描，多個目錄用逗號或者分號分隔(告訴 Mapper 所對應的 XML 文件位置)
mapper-locations: classpath:mapper/*.xml
configuration:
# 是否開啟自動駝峰命名規則映射:從數據庫列名到Java屬性駝峰命名的類似映射
map-underscore-to-camel-case: true
# 如果查詢結果中包含空值的列，則 MyBatis 在映射的時候，不會映射這個字段
call-setters-on-nulls: true
# 這個配置會將執行的sql打印出來，在開發或測試的時候可以用
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
# 實體掃描，多個package用逗號或者分號分隔（這里更改為你的實體類存放路徑）
typeAliasesPackage: com.example.study.model.entity
global-config:
db-config:
#主鍵類型 AUTO:"數據庫ID自增" INPUT:"用戶輸入ID",ID_WORKER:"全局唯一ID (數字類型唯一ID)", UUID:"全局唯一ID UUID";
id-type: auto
#字段策略 IGNORED:"忽略判斷" NOT_NULL:"非 NULL 判斷") NOT_EMPTY:"非空判斷"
field-strategy: NOT_EMPTY
#數據庫類型
db-type: MYSQL
# 邏輯刪除配置
# 刪除前
logic-not-delete-value: 1
# 刪除后
logic-delete-value: 0
#----------------swagger配置-----------------------
swagger:
#生產環境改為false（改為false后swagger-ui.html則無法訪問）
enable: true
#解決Swagger2 異常 NumberFormatException:For input string:""
logging:
level:
io:
swagger:
models:
parameters:
AbstractSerializableParameter: ERROR
3、添加druid配置類DruidConfig.java
package com.example.study.config;
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import javax.sql.DataSource;
import java.util.HashMap;
import java.util.Map;
/**
* druid配置類
*
* @author 154594742@qq.com
* @date: 2021/2/22 10:02:00
*/
@Configuration
@ServletComponentScan
public class DruidConfig {
@Bean
@ConfigurationProperties(prefix = "spring.datasource.druid") //加載時讀取指定的配置信息,前綴為spring.datasource.druid
public DataSource druidDataSource() {
return new DruidDataSource();
}
@Bean
public ServletRegistrationBean StatViewServlet() {
//設置druid的dashboard訪問路徑（ip:端口/druid/）
ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");
Map<String, String> map = new HashMap<>(1);
//durid監控登錄賬戶和密碼，這里可以注釋掉改為shiro或者別的方式去做訪問控制
map.put("loginUsername", "admin");
map.put("loginPassword", "admin2012!");
//允許訪問
map.put("allow", "");
//設置屬性進注冊servlet
bean.setInitParameters(map);
return bean;
}
}
二、整合Swagger2
1、添加swagger的配置類SwaggerConfig.java
package com.example.study.config;
import io.swagger.annotations.Api;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.ApiKey;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;
import java.util.ArrayList;
import java.util.List;
/**
* Swagger配置類
*
* @author 154594742@qq.com
* @date: 2021/2/22 10:02:00
*/
@Configuration
@EnableSwagger2
@ConditionalOnProperty(name = "swagger.enable", havingValue = "true")
public class SwaggerConfig {
/**
* 創建API應用
* apiInfo() 增加API相關信息
* 通過select()函數返回一個ApiSelectorBuilder實例,用來控制哪些接口暴露給Swagger來展現，
* 本例采用指定掃描的包路徑來定義指定要建立API的目錄。
*
* @return
*/
@Bean
public Docket createRestApi() {
return new Docket(DocumentationType.SWAGGER_2)
.apiInfo(this.apiInfo())
.select()
//設置選擇器，選擇帶Api接口類的類
.apis(RequestHandlerSelectors.withClassAnnotation(Api.class))
//api包掃描
.apis(RequestHandlerSelectors.basePackage("com.example.study"))
.paths(PathSelectors.any())
.build()
.securitySchemes(securitySchemes());
}
/**
* 創建該API的基本信息（這些基本信息會展現在文檔頁面中）
* 訪問地址：http://ip:端口/swagger-ui.html
*
* @return ApiInfo
*/
private ApiInfo apiInfo() {
return new ApiInfoBuilder().title("demo項目")
.description("demo項目API文檔")
.termsOfServiceUrl("http://localhost")
.version("1.0")
.build();
}
private List<ApiKey> securitySchemes() {
List<ApiKey> apiKeyList= new ArrayList<>();
//apiKeyList.add(new ApiKey("token", "令牌", "header"));
return apiKeyList;
}
}
2、新建controller包並且在controller包下新建IndexController.java
package com.example.study.controller;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
/**
* 首頁控制器
* @author 154594742@qq.com
* @date: 2021/2/22 10:02:00
*/
@Api(tags = "首頁控制器")
@RestController
public class IndexController {
@ApiOperation("首頁html")
@GetMapping("/")
public String index(){
return "hello index";
}
}
3、啟動StudyApplication.java后訪問 http://localhost:8080/swagger-ui.html ，出現第二圖所示則表示swagger整合完成
三、整合Mybatis Plus
1、如圖創建MybatisPlusConfi.java配置分頁插件
package com.example.study.config;
import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.autoconfigure.ConfigurationCustomizer;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
* 配置MybatisPlus分頁插件
*
* *@MapperScan注解的作用相當於在com.example.study.mapper下的所有類上面添加@Mapper注解
*
* @author 154594742@qq.com
* @date: 2021/2/22 10:02:00
*/
@Configuration
@MapperScan("com.example.study.mapper")
public class MybatisPlusConfig {
/**
* Mybatis-plus3.4.0版本過后使用MybatisPlusInterceptor分頁插件
* 注意：DbType.MYSQL必須為自己使用的數據庫類型，否則分頁不生效
*/
@Bean
public MybatisPlusInterceptor mybatisPlusInterceptor() {
MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
return interceptor;
}
/**
* 設置useDeprecatedExecutor = false 避免緩存出現問題
* @return
*/
@Bean
public ConfigurationCustomizer configurationCustomizer() {
return configuration -> configuration.setUseDeprecatedExecutor(false);
}
}
2、在數據庫中創建測試表
CREATE TABLE `t_user` (
`id` bigint NOT NULL AUTO_INCREMENT,
`name` varchar(32) DEFAULT NULL,
`age` int DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
3、創建實體類UserEntity.java
package com.example.study.model.entity;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.io.Serializable;
/**
* 用戶信息實體類
*
* @author 154594742@qq.com
* @date: 2021/2/22 10:02:00
*/
@Data
@NoArgsConstructor
@AllArgsConstructor
@ApiModel(value = "UserEntity", description = "用戶實體")
@TableName("t_user")
public class UserEntity implements Serializable {
private static final long serialVersionUID = 6928834261563057243L;
/**
* 唯一標識，自增主鍵
*/
@ApiModelProperty(value = "id")
@TableId(value = "id", type = IdType.AUTO)
private Long id;
/**
* 姓名
*/
@ApiModelProperty(value = "姓名")
@TableField("name")
private String name;
/**
* 年齡
*/
@ApiModelProperty(value = "年齡")
@TableField("age")
private Integer age;
}
4、創建UserMapper.java
package com.example.study.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.study.model.entity.UserEntity;
/**
* @author 154594742@qq.com
*/
public interface UserMapper extends BaseMapper<UserEntity> {
}
5、創建UserService.java
package com.example.study.service;
import com.baomidou.mybatisplus.extension.service.IService;
import com.example.study.model.entity.UserEntity;
/**
* @author 154594742@qq.com
*/
public interface UserService extends IService<UserEntity> {
}
6、創建UserServiceImpl.java
package com.example.study.service.impl;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.study.model.entity.UserEntity;
import com.example.study.mapper.UserMapper;
import com.example.study.service.UserService;
import org.springframework.stereotype.Service;
/**
* @author 154594742@qq.com
*/
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, UserEntity> implements UserService {
}
7、創建UserController.java(這里編譯器會提示一些錯誤暫時不用管，因為缺少一些類的代碼)
package com.example.study.controller;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.example.study.model.entity.UserEntity;
import com.example.study.model.param.UserParam;
import com.example.study.model.vo.ResponseVo;
import com.example.study.service.UserService;
import com.example.study.util.CommonQueryPageUtils;
import com.example.study.util.BuildResponseUtils;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
/**
* 用戶控制器（一個demo用於大家學習參考）
*
* @author 154594742@qq.com
* @date: 2021/2/22 10:02:00
*/
@RestController
@Api(tags = "用戶控制器")
public class UserController {
@Autowired
private UserService userService;
/**
* 新增
*
* @param entity 實體
* @return ResponseVo
*/
@ApiOperation("新增")
@PostMapping("user")
public ResponseVo<?> add(UserEntity entity) {
return BuildResponseUtils.buildResponse(userService.save(entity));
}
/**
* 通過id查詢
*
* @param id 自增主鍵
* @return ResponseVo
*/
@ApiOperation("通過id查詢")
@GetMapping("user/{id}")
public ResponseVo<UserEntity> getById(@PathVariable String id) {
return BuildResponseUtils.buildResponse(userService.getById(id));
}
/**
* 更新
*
* @param entity 實體
* @return ResponseVo
*/
@ApiOperation("更新")
@PutMapping("user")
public ResponseVo<?> update(UserEntity entity) {
return BuildResponseUtils.buildResponse(userService.updateById(entity));
}
/**
* 通過id刪除
*
* @param id 自增主鍵
* @return ResponseVo
*/
@ApiOperation("通過id刪除")
@DeleteMapping("user/{id}")
public ResponseVo<?> delete(@PathVariable String id) {
return BuildResponseUtils.buildResponse(userService.removeById(id));
}
/**
* 分頁查詢
*
* @param param 請求參數
* @return ResponseVo
*/
@ApiOperation("分頁查詢")
@GetMapping("userPage")
public ResponseVo<IPage<UserEntity>> selectPage(UserParam param) {
return BuildResponseUtils.buildResponse(CommonQueryPageUtils.commonQueryPage(param, userService));
}
}
8、創建枚舉CodeMsgEnum.java
package com.example.study.enums;
/**
* 異常類code常量（code值不要重復）
*
* @author 154594742@qq.com
* @date: 2021/2/22 9:42:00
*/
public enum CodeMsgEnum {
//請求成功
SUCCESS("0","成功!"),
//系統異常
FAIL("1","失敗!"),
//以下是業務異常
LOGIN_NO_PASS("1001","用戶名或密碼錯誤"),
;
/**
* 狀態碼
*/
public String code;
/**
* 狀態碼對應信息
*/
public String msg;
CodeMsgEnum(String code, String msg) {
this.code = code;
this.msg = msg;
}
}
9、創建統一的返回結果類ResponseVo.java
package com.example.study.model.vo;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.io.Serializable;
/**
* 統一的返回對象VO
*
* @author 154594742@qq.com
* @date: 2021/2/22 10:02:00
*/
@Data
@NoArgsConstructor
@AllArgsConstructor
@ApiModel(value = "ResponseVo", description = "統一的返回對象")
public class ResponseVo<T> implements Serializable {
private static final long serialVersionUID = 7748070653645596712L;
/**
* 狀態碼
*/
@ApiModelProperty(value = "狀態碼")
private String code;
/**
* 狀態碼對應描述信息
*/
@ApiModelProperty(value = "狀態碼對應描述信息")
private String msg;
/**
* 數據
*/
@ApiModelProperty(value = "數據")
private T data;
}
10、創建常量類QueryMethodConstant.java
package com.example.study.constant;
/**
* mybatis plus常用的查詢方式
* @author 154594742@qq.com
* @date 2021/2/23 11:24
*/
public interface QueryMethodConstant {
/**
* 相同
*/
String EQ = "EQ";
/**
* 不相同
*/
String NE = "NE";
/**
* 相似，左右模糊(like '%值%')
*/
String LIKE = "LIKE";
/**
* 相似，左模糊(like '%值')
*/
String LIKE_LIFT = "LIKE_LIFT";
/**
* 相似，右模糊(like '值%')
*/
String LIKE_RIGHT = "LIKE_RIGHT";
/**
* 不相似 (not like '%值%')
*/
String NOT_LIKE = "NOT_LIKE";
/**
* 大於
*/
String GT = "GT";
/**
* 大於等於
*/
String GE = "GE";
/**
* 小於
*/
String LT = "LT";
/**
* 小於等於
*/
String LE = "LE";
}
11、創建自定義注解QueryMethod.java(用於后續的通用分頁查詢工具類)
package com.example.study.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* 查詢方式的自定義注解
* @author 154594742@qq.com
* @date 2021/2/23 11:24
*/
@Retention(RetentionPolicy.RUNTIME)
@Target(value = ElementType.FIELD)
public @interface QueryMethod {
/**
* 字段名
*/
String field() default "";
/**
* 匹配方式
*/
String method() default "";
}
12、創建構建返回結果工具類BuildResponseUtils.java
package com.example.study.util;
import com.example.study.enums.CodeMsgEnum;
import com.example.study.model.vo.ResponseVo;
/**
* 構建返回結果工具類
*
* @author 154594742@qq.com
* @date: 2021/2/22 10:02:00
*/
public final class BuildResponseUtils {
/**
* 構建正確請求的response
*
* @return ResponseVo 統一的返回結果
*/
public static ResponseVo<?> success() {
ResponseVo<?> response = new ResponseVo<>();
response.setCode(CodeMsgEnum.SUCCESS.code);
response.setMsg(CodeMsgEnum.SUCCESS.msg);
return response;
}
/**
* 構建業務異常的response
* @param codeMsgEnum 枚舉
* @return ResponseVo 統一的返回結果
*/
public static ResponseVo<?> success(CodeMsgEnum codeMsgEnum) {
ResponseVo<?> response = new ResponseVo<>();
response.setCode(codeMsgEnum.code);
response.setMsg(codeMsgEnum.msg);
return response;
}
/**
* 構建自定義code和msg的業務異常
*
* @param code 自定義code
* @param msg 自定義msg
* @return ResponseVo 統一的返回結果
*/
public static ResponseVo<?> success(String code, String msg) {
ResponseVo<?> response = new ResponseVo<>();
response.setCode(code);
response.setMsg(msg);
return response;
}
/**
* 構建系統異常的response(只用於系統異常)
* @return ResponseVo 統一的返回結果
*/
public static ResponseVo<?> error() {
ResponseVo<?> response = new ResponseVo<>();
response.setCode(CodeMsgEnum.FAIL.code);
response.setMsg(CodeMsgEnum.FAIL.msg);
return response;
}
/**
* 構建返回結果
* @param obj 結果數據
* @param <T> 結果數據的泛型
* @return ResponseVo 統一的返回結果
*/
public static <T> ResponseVo<T> buildResponse(T obj) {
ResponseVo<T> response = new ResponseVo<>();
response.setData(obj);
response.setCode(CodeMsgEnum.SUCCESS.code);
response.setMsg(CodeMsgEnum.SUCCESS.msg);
return response;
}
}
13、創建分頁查詢工具類CommonQueryPageUtils.java(本人自己封裝的，功能可能不是很完善，但是基本的單表查詢夠用了)
package com.example.study.util;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.core.metadata.OrderItem;
import com.baomidou.mybatisplus.core.toolkit.StringUtils;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.IService;
import com.example.study.annotation.QueryMethod;
import com.example.study.constant.QueryMethodConstant;
import com.example.study.model.param.PageParam;
import java.lang.reflect.Field;
import java.util.Locale;
/**
* 分頁查詢工具類
*
* @author 154594742@qq.com
* @date: 2021/2/22 10:02:00
*/
public final class CommonQueryPageUtils {
/**
* 正序
*/
private static final String ASC = "asc";
/**
* 倒序
*/
private static final String DESC = "desc";
/**
* 通用的帶排序功能的分頁查詢
*/
public static <T> IPage<T> commonQueryPage(PageParam param, IService<T> service) {
//構建page
//根據傳入的排序設置order
//排序字段(格式：字段名:排序方式，字段名:排序方式 （asc正序，desc倒序） 示例:id:desc,age:asc)
Page<T> page = new Page<>(param.getPage(), param.getLimit());
String orders = param.getOrders();
if (StringUtils.isNotBlank(orders)) {
String[] splitArr = orders.split(",");
for (String str : splitArr) {
if (StringUtils.isBlank(str)) {
continue;
}
String[] strArr = str.split(":");
if (strArr.length != 2 || StringUtils.isBlank(strArr[0]) || StringUtils.isBlank(strArr[1])) {
continue;
}
if (ASC.equals(strArr[1].toLowerCase(Locale.ROOT))) {
page.addOrder(OrderItem.asc(strArr[0]));
continue;
}
if (DESC.equals(strArr[1].toLowerCase(Locale.ROOT))) {
page.addOrder(OrderItem.desc(strArr[0]));
}
}
}
//根據自定義注解構建queryWrapper
QueryWrapper<T> queryWrapper = new QueryWrapper<>();
Class<? extends PageParam> clazz = param.getClass();
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
//設置對象的訪問權限，保證對private的屬性可以訪問
field.setAccessible(true);
QueryMethod annotation = field.getAnnotation(QueryMethod.class);
try {
//屬性沒有值則跳過
if (null == field.get(param)) {
continue;
}
//沒有加@QueryMethod 默認屬性名為字段名，默認匹配方式為eq
if (null == annotation) {
queryWrapper.eq(field.getName(), field.get(param));
continue;
}
switch (annotation.method()) {
case QueryMethodConstant.EQ:
queryWrapper.eq(annotation.field(), field.get(param));
break;
case QueryMethodConstant.NE:
queryWrapper.ne(annotation.field(), field.get(param));
break;
case QueryMethodConstant.LIKE:
queryWrapper.like(annotation.field(), field.get(param));
break;
case QueryMethodConstant.LIKE_LIFT:
queryWrapper.likeLeft(annotation.field(), field.get(param));
break;
case QueryMethodConstant.LIKE_RIGHT:
queryWrapper.likeRight(annotation.field(), field.get(param));
break;
case QueryMethodConstant.GT:
queryWrapper.gt(annotation.field(), field.get(param));
break;
case QueryMethodConstant.GE:
queryWrapper.ge(annotation.field(), field.get(param));
break;
case QueryMethodConstant.LT:
queryWrapper.lt(annotation.field(), field.get(param));
break;
case QueryMethodConstant.LE:
queryWrapper.le(annotation.field(), field.get(param));
break;
default:
;
}
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
return service.page(page, queryWrapper);
}
}
14、創建統一的分頁查詢請求參數類PageParam.java
package com.example.study.model.param;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;
import java.util.LinkedHashMap;
/**
* 統一的分頁查詢請求參數
*
* @author 154594742@qq.com
* @date 2021/2/22 17:24
*/
@Data
@ApiModel(value = "PageParam", description = "分頁參數")
public class PageParam {
/**
* 頁碼
*/
@ApiModelProperty(value = "頁碼，不傳則默認1")
private Integer page = 1;
/**
* 每頁條數
*/
@ApiModelProperty(value = "每頁條數，不傳則默認10")
private Integer limit = 10;
/**
* 排序字段(格式：字段名:排序方式，字段名:排序方式 （asc正序，desc倒序） 示例:id:desc,age:asc)
*/
@ApiModelProperty(value = "排序字段(格式：字段名:排序方式，字段名:排序方式 （asc正序，desc倒序） 示例:id:desc,age:asc)")
private String orders;
}
15、創建用戶查詢條件類UserParam.java繼承PageParam（以后分頁查詢的參數類都要繼承PageParam）
package com.example.study.model.param;
import com.example.study.annotation.QueryMethod;
import com.example.study.constant.QueryMethodConstant;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;
/**
* 用戶查詢條件類（需要根據哪些字段查詢就添加哪些字段）
* @author 154594742@qq.com
* @date 2021/2/22 17:24
*/
@Data
@ApiModel(value = "UserParam", description = "用戶查詢條件")
public class UserParam extends PageParam {
/**
* 通過@QueryMethod注解來控制匹配的方式，這里查詢條件為 name like ‘%值%’
*/
@ApiModelProperty(value = "姓名")
@QueryMethod(field = "name", method = QueryMethodConstant.LIKE)
private String name;
/**
* 這里沒有@QueryMethod注解則如果age有值，則默認查詢條件為 age=值
*/
@ApiModelProperty(value = "年齡")
private Integer age;
/**
* 假如要查詢 (值1 < age < 值2)則可以采用如下方式添加兩個屬性minAge和maxAge，
* ‘ @QueryMethod 注解的field是數據表字段名，method是查詢方式
* 假如minAge = 18，maxAge=25，則通過CommonQueryPageUtils工具類會構建出的sql為 18<age AND age<25
*/
@ApiModelProperty(value = "年齡下限")
@QueryMethod(field = "age", method = QueryMethodConstant.GT)
private String minAge;
@ApiModelProperty(value = "年齡上限")
@QueryMethod(field = "age", method = QueryMethodConstant.LT)
private String maxAge;
}
16、先在數據庫中添加幾條測試數據，然后啟動項目后打開 http://localhost:8080/swagger-ui.html
insert into `t_user`(`id`,`name`,`age`) values
(1,'小二',20),
(2,'張三',20),
(3,'李四',20),
(4,'王五',35),
(5,'小六',18);
17、按上圖填入查詢條件，然后點擊“Execute”執行
返回的Response body：
{
"code": "0",
"msg": "成功!",
"data": {
"records": [
{
"id": 5,
"name": "小六",
"age": 18
},
{
"id": 1,
"name": "小二",
"age": 20
},
{
"id": 2,
"name": "張三",
"age": 20
},
{
"id": 3,
"name": "李四",
"age": 20
}
],
"total": 4,
"size": 10,
"current": 1,
"orders": [
{
"column": "age",
"asc": true
}
],
"optimizeCountSql": true,
"hitCount": false,
"countId": null,
"maxLimit": null,
"searchCount": true,
"pages": 1
}
}
通過上面的返回結果可以看出我們帶條件帶排序的分頁查詢功能是ok的！新增、修改和刪除沒啥好說的大家可以自行體驗！