SpringBoot整合Mybatis-plus案例及用法实例
目录
- 一、mybatis-plus简介:
- 二、springboot整合mybatis-plus案例
- mybatis plus强大的条件构造器queryWrapper、updateWrapper
- 总结
一、mybatis-plus简介:
Mybatis-Plus(简称MP)是一个 Mybatis 的增强工具,在 Mybatis 的基础上只做增强不做改变,为简化开发、提高效率而生。这是官方给的定义,关于mybatis-plus的更多介绍及特性,可以参考mybatis-plus官网。那么它是怎么增强的呢?其实就是它已经封装好了一些crud方法,我们不需要再写xml了,直接调用这些方法就行,就类似于JPA。并且3.X系列支持lambda语法,让我在写条件构造的时候少了很多的"魔法值",从代码结构上更简洁了.
二、springboot整合mybatis-plus案例
pom.xml配置
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> <!--springboot程序测试依赖,如果是自动创建项目默认添加--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.16.10</version> <scope>provided</scope> </dependency> <!-- 包含spirng Mvc ,tomcat的包包含requestMapping restController 等注解 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>1.1.10</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <!-- druid依赖 --> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.1.0</version> </dependency> <!-- mybatisPlus 核心库 --> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.1.0</version> </dependency> </dependencies>
application.yml配置
server: port: 10100 # 配置启动端口号 mybatis: config-location: classpath:mybatis.cfg.xml # mybatis主配置文件所在路径 type-aliases-package: com.demo.drools.entity # 定义所有操作类的别名所在包 mapper-locations: # 所有的mapper映射文件 - classpath:mapper/*.xml spring: #springboot的配置 datasource: #定义数据源 #127.0.0.1为本机测试的ip,3306是mysql的端口号。serverTimezone是定义时区,照抄就好,mysql高版本需要定义这些东西 #useSSL也是某些高版本mysql需要问有没有用SSL连接 url: jdbc:mysql://127.0.0.1:3306/test?serverTimezone=GMT%2B8&useSSL=FALSE username: root #数据库用户名,root为管理员 password: 123456 #该数据库用户的密码 # 使用druid数据源 type: com.alibaba.druid.pool.DruidDataSource # mybatis-plus相关配置 mybatis-plus: # xml扫描,多个目录用逗号或者分号分隔(告诉 Mapper 所对应的 XML 文件位置) mapper-locations: classpath:mapper/*.xml # 以下配置均有默认值,可以不设置 global-config: db-config: #主键类型 AUTO:"数据库ID自增" INPUT:"用户输入ID",ID_WORKER:"全局唯一ID (数字类型唯一ID)", UUID:"全局唯一ID UUID"; id-type: auto #字段策略 IGNORED:"忽略判断" NOT_NULL:"非 NULL 判断") NOT_EMPTY:"非空判断" field-strategy: NOT_EMPTY #数据库类型 db-type: MYSQL configuration: # 是否开启自动驼峰命名规则映射:从数据库列名到Java属性驼峰命名的类似映射 map-underscore-to-camel-case: true # 如果查询结果中包含空值的列,则 MyBatis 在映射的时候,不会映射这个字段 call-setters-on-nulls: true # 这个配置会将执行的sql打印出来,在开发或测试的时候可以用 log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
用户信息实体
package com.demo.drools.entity; import com.baomidou.mybatisplus.annotation.IdType; import com.baomidou.mybatisplus.annotation.TableId; import com.baomidou.mybatisplus.annotation.TableName; import lombok.Data; /** * TODO your comment * * @author Yujiaqi * @date 2020/12/2 19:14 */ @Data @TableName("user_info")//@TableName中的值对应着表名 public class UserInfoEntity { /** * 主键 * @TableId中可以决定主键的类型,不写会采取默认值,默认值可以在yml中配置 * AUTO: 数据库ID自增 * INPUT: 用户输入ID * ID_WORKER: 全局唯一ID,Long类型的主键 * ID_WORKER_STR: 字符串全局唯一ID * UUID: 全局唯一ID,UUID类型的主键 * NONE: 该类型为未设置主键类型 */ @TableId(type = IdType.AUTO) private Long id; /** * 姓名 */ private String name; /** * 年龄 */ private Integer age; /** * 技能 */ private String skill; /** * 评价 */ private String evaluate; /** * 分数 */ private Long fraction; }
config类
package com.demo.drools.config; import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor; import com.baomidou.mybatisplus.extension.plugins.PerformanceInterceptor; import org.springframework.context.annotation.Bean; /** * TODO your comment * * @author Yujiaqi * @date 2020/12/2 19:14 */ public class MybatisPlusConfig { /** * mybatis-plus SQL执行效率插件【生产环境可以关闭】 */ @Bean public PerformanceInterceptor performanceInterceptor() { return new PerformanceInterceptor(); } /** * 分页插件 */ @Bean public PaginationInterceptor paginationInterceptor() { return new PaginationInterceptor(); } }
spring boot启动类
package com.demo.drools; import org.mybatis.spring.annotation.MapperScan; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; /** * @author 于嘉琪 */ @SpringBootApplication //@MapperScan和dao层添加@Mapper注解意思一样 @MapperScan(basePackages = "com.demo.drools.dao") public class DroolsApplication { public static void main(String[] args) { SpringApplication.run(DroolsApplication.class, args); } }
dao层
package com.demo.drools.dao; import com.baomidou.mybatisplus.core.mapper.BaseMapper; import com.baomidou.mybatisplus.core.metadata.IPage; import com.demo.drools.entity.UserInfoEntity; import org.apache.ibatis.annotations.Mapper; import org.apache.ibatis.annotations.Param; /** * 用户信息DAO * * @author Yujiaqi * @date 2020/12/2 19:16 */ @Mapper public interface UserInfoDao extends BaseMapper<UserInfoEntity> { }
service层
package com.demo.drools.service; import com.baomidou.mybatisplus.core.metadata.IPage; import com.baomidou.mybatisplus.extension.service.IService; import com.demo.drools.entity.UserInfoEntity; /** * TODO your comment * * @author Yujiaqi * @date 2020/12/2 19:17 */ public interface UserInfoService extends IService<UserInfoEntity> { }
serviceImpl实现类层
package com.demo.drools.service.impl; import com.baomidou.mybatisplus.core.metadata.IPage; import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl; import com.demo.drools.dao.UserInfoDao; import com.demo.drools.entity.UserInfoEntity; import com.demo.drools.service.UserInfoService; import org.springframework.stereotype.Service; import javax.annotation.Resource; /** * TODO your comment * * @author Yujiaqi * @date 2020/12/2 19:18 */ @Service public class UserInfoSerivceImpl extends ServiceImpl<UserInfoDao, UserInfoEntity> implements UserInfoService { }
controller控制层
package com.demo.drools.controller; import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper; import com.baomidou.mybatisplus.core.metadata.IPage; import com.baomidou.mybatisplus.extension.plugins.pagination.Page; import com.demo.drools.entity.UserInfoEntity; import com.demo.drools.service.UserInfoService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import java.util.HashMap; import java.util.List; import java.util.Map; /** * TODO your comment * * @author Yujiaqi * @date 2020/12/2 19:28 */ public class UserInfoPlusController { @Autowired private UserInfoService userInfoService; /** * MP扩展演示 * @Author Sans * @CreateTime 2019/6/8 16:37 * @Return Map<String,Object> 返回数据 */ @RequestMapping("/getInfoListPlus") public Map<String,Object> getInfoListPage(){ //初始化返回类 Map<String,Object> result = new HashMap<>(); //查询年龄等于18岁的学生 //等价SQL: SELECT id,name,age,skill,evaluate,fraction FROM user_info WHERE age = 18 QueryWrapper<UserInfoEntity> queryWrapper1 = new QueryWrapper<>(); queryWrapper1.lambda().eq(UserInfoEntity::getAge,18); List<UserInfoEntity> userInfoEntityList1 = userInfoService.list(queryWrapper1); result.put("studentAge18",userInfoEntityList1); //查询年龄大于5岁的学生且小于等于18岁的学生 //等价SQL: SELECT id,name,age,skill,evaluate,fraction FROM user_info WHERE age > 5 AND age <= 18 QueryWrapper<UserInfoEntity> queryWrapper2 = new QueryWrapper<>(); queryWrapper2.lambda().gt(UserInfoEntity::getAge,5); queryWrapper2.lambda().le(UserInfoEntity::getAge,18); List<UserInfoEntity> userInfoEntityList2 = userInfoService.list(queryWrapper2); result.put("studentAge5",userInfoEntityList2); //模糊查询技能字段带有"画"的数据,并按照年龄降序 //等价SQL: SELECT id,name,age,skill,evaluate,fraction FROM user_info WHERE skill LIKE '%画%' ORDER BY age DESC QueryWrapper<UserInfoEntity> queryWrapper3 = new QueryWrapper<>(); queryWrapper3.lambda().like(UserInfoEntity::getSkill,"画"); queryWrapper3.lambda().orderByDesc(UserInfoEntity::getAge); List<UserInfoEntity> userInfoEntityList3 = userInfoService.list(queryWrapper3); result.put("studentAgeSkill",userInfoEntityList3); //模糊查询名字带有"小"或者年龄大于18的学生 //等价SQL: SELECT id,name,age,skill,evaluate,fraction FROM user_info WHERE name LIKE '%小%' OR age > 18 QueryWrapper<UserInfoEntity> queryWrapper4 = new QueryWrapper<>(); queryWrapper4.lambda().like(UserInfoEntity::getName,"小"); queryWrapper4.lambda().or().gt(UserInfoEntity::getAge,18); List<UserInfoEntity> userInfoEntityList4 = userInfoService.list(queryWrapper4); result.put("studentOr",userInfoEntityList4); //查询评价不为null的学生,并且分页 //等价SQL: SELECT id,name,age,skill,evaluate,fraction FROM user_info WHERE evaluate IS NOT NULL LIMIT 0,5 IPage<UserInfoEntity> page = new Page<>(); page.setCurrent(1); page.setSize(5); QueryWrapper<UserInfoEntity> queryWrapper5 = new QueryWrapper<>(); queryWrapper5.lambda().isNotNull(UserInfoEntity::getEvaluate); page = userInfoService.page(page,queryWrapper5); result.put("studentPage",page); return result; } }
controller层用到lambda语法
package com.demo.drools.controller; import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper; import com.baomidou.mybatisplus.core.metadata.IPage; import com.baomidou.mybatisplus.extension.plugins.pagination.Page; import com.demo.drools.entity.UserInfoEntity; import com.demo.drools.service.UserInfoService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import java.util.HashMap; import java.util.List; import java.util.Map; /** * TODO your comment * * @author Yujiaqi * @date 2020/12/2 19:28 */ public class UserInfoPlusController { @Autowired private UserInfoService userInfoService; /** * MP扩展演示 * @Author Sans * @CreateTime 2019/6/8 16:37 * @Return Map<String,Object> 返回数据 */ @RequestMapping("/getInfoListPlus") public Map<String,Object> getInfoListPage(){ //初始化返回类 Map<String,Object> result = new HashMap<>(); //查询年龄等于18岁的学生 //等价SQL: SELECT id,name,age,skill,evaluate,fraction FROM user_info WHERE age = 18 QueryWrapper<UserInfoEntity> queryWrapper1 = new QueryWrapper<>(); queryWrapper1.lambda().eq(UserInfoEntity::getAge,18); List<UserInfoEntity> userInfoEntityList1 = userInfoService.list(queryWrapper1); result.put("studentAge18",userInfoEntityList1); //查询年龄大于5岁的学生且小于等于18岁的学生 //等价SQL: SELECT id,name,age,skill,evaluate,fraction FROM user_info WHERE age > 5 AND age <= 18 QueryWrapper<UserInfoEntity> queryWrapper2 = new QueryWrapper<>(); queryWrapper2.lambda().gt(UserInfoEntity::getAge,5); queryWrapper2.lambda().le(UserInfoEntity::getAge,18); List<UserInfoEntity> userInfoEntityList2 = userInfoService.list(queryWrapper2); result.put("studentAge5",userInfoEntityList2); //模糊查询技能字段带有"画"的数据,并按照年龄降序 //等价SQL: SELECT id,name,age,skill,evaluate,fraction FROM user_info WHERE skill LIKE '%画%' ORDER BY age DESC QueryWrapper<UserInfoEntity> queryWrapper3 = new QueryWrapper<>(); queryWrapper3.lambda().like(UserInfoEntity::getSkill,"画"); queryWrapper3.lambda().orderByDesc(UserInfoEntity::getAge); List<UserInfoEntity> userInfoEntityList3 = userInfoService.list(queryWrapper3); result.put("studentAgeSkill",userInfoEntityList3); //模糊查询名字带有"小"或者年龄大于18的学生 //等价SQL: SELECT id,name,age,skill,evaluate,fraction FROM user_info WHERE name LIKE '%小%' OR age > 18 QueryWrapper<UserInfoEntity> queryWrapper4 = new QueryWrapper<>(); queryWrapper4.lambda().like(UserInfoEntity::getName,"小"); queryWrapper4.lambda().or().gt(UserInfoEntity::getAge,18); List<UserInfoEntity> userInfoEntityList4 = userInfoService.list(queryWrapper4); result.put("studentOr",userInfoEntityList4); //查询评价不为null的学生,并且分页 //等价SQL: SELECT id,name,age,skill,evaluate,fraction FROM user_info WHERE evaluate IS NOT NULL LIMIT 0,5 IPage<UserInfoEntity> page = new Page<>(); page.setCurrent(1); page.setSize(5); QueryWrapper<UserInfoEntity> queryWrapper5 = new QueryWrapper<>(); queryWrapper5.lambda().isNotNull(UserInfoEntity::getEvaluate); page = userInfoService.page(page,queryWrapper5); result.put("studentPage",page); return result; } }
以上就是mybatis-plus的小案例,mybatis-plus它像我之前使用的spring data jpa框架不用写sql语句,就可以实现简单的增删改查、批量操作、分页mybatis-plus功能还是比较强大,能减少我们写很多代码,我个人还是比较喜欢用这个mybatis-plus的
mybatis-plus只是mybatis的增强版,它不影响mybatis的使用,我们可以写我们自定的方法以及sql,接下来我们看一个小案例
dao层新增方法
/** * 查询大于该分数的学生 * @Author Sans * @CreateTime 2019/6/9 14:28 * @Param page 分页参数 * @Param fraction 分数 * @Return IPage<UserInfoEntity> 分页数据 */ IPage<UserInfoEntity> selectUserInfoByGtFraction( @Param(value = "page") IPage<UserInfoEntity> page, @Param(value = "fraction")Long fraction);
service新增方法
/** * 查询大于该分数的学生 * @Author Sans * @CreateTime 2019/6/9 14:27 * @Param page 分页参数 * @Param fraction 分数 * @Return IPage<UserInfoEntity> 分页数据 */ IPage<UserInfoEntity> selectUserInfoByGtFraction(IPage<UserInfoEntity> page,Long fraction);
serviceImpl层新增方法
/** * 查询大于该分数的学生 * @Author Sans * @CreateTime 2019/6/9 14:27 * @Param page 分页参数 * @Param fraction 分数 * @Return IPage<UserInfoEntity> 分页数据 */ @Override public IPage<UserInfoEntity> selectUserInfoByGtFraction(IPage<UserInfoEntity> page, Long fraction) { return userInfoDao.selectUserInfoByGtFraction(page,fraction); }
controller层新增方法
/** * MP自定义SQL * @Author Sans * @CreateTime 2019/6/9 14:37 * @Return IPage<UserInfoEntity> 分页数据 */ @RequestMapping("/getInfoListSQL") public IPage<UserInfoEntity> getInfoListSQL(){ //查询大于60分以上的学生,并且分页 IPage<UserInfoEntity> page = new Page<>(); page.setCurrent(1); page.setSize(5); page = userInfoService.selectUserInfoByGtFraction(page,60L); return page; }
配置我们的mybatis的xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace="com.demo.drools.dao.UserInfoDao"> <!-- Sans 2019/6/9 14:35 --> <select id="selectUserInfoByGtFraction" resultType="com.demo.drools.entity.UserInfoEntity"> SELECT * FROM user_info WHERE fraction > #{fraction} </select> </mapper>
以上配置就是我们的mybatis用法。
mybatis plus强大的条件构造器queryWrapper、updateWrapper
1.QueryWrapper: Entity 对象封装操作类
2.UpdateWrapper : Update 条件封装,用于Entity对象更新操作
3.条件构造器使用中的各个方法格式和说明
总结
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