快速入门
创建表
create database mybatis_plus;
use mybatis_plus;
create table user(id bigint(20) not null comment '主键ID',name varchar(30) default null comment '姓名',age int(11) default null comment '年龄',email varchar(50) default null comment '邮箱',primary key (id)
)engine =InnoDB default charset =utf8;
添加数据
INSERT INTO `user` (id, name, age, email) VALUES
(1, 'Jone', 18, 'test1@baomidou.com'),
(2, 'Jack', 20, 'test2@baomidou.com'),
(3, 'Tom', 28, 'test3@baomidou.com'),
(4, 'Sandy', 21, 'test4@baomidou.com'),
(5, 'Billie', 24, 'test5@baomidou.com');
导依赖
<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.4.3</version>
</dependency>
<dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional>
</dependency>
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.33</version><scope>runtime</scope>
</dependency>
配置文件
spring.datasource.type=com.zaxxer.hikari.HikariDataSource
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring:# 配置数据源信息datasource:# 配置数据源类型type: com.zaxxer.hikari.HikariDataSource# 配置连接数据库的各个信息driver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=falseusername: rootpassword: 20050606a
实体类
package com.wang.mybatisplusexe.pojo;import lombok.Data;@Data
public class User {private Long id;private String name;private Integer age;private String email;
}
package com.wang.mybatisplusexe.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.wang.mybatisplusexe.pojo.User;public interface UserMapper extends BaseMapper<User> {}
package com.wang.mybatisplusexe;import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication
//扫描mapper接口所在的包
@MapperScan("com.wang.mybatisplusexe.mapper")
public class MybatisPlusExeApplication {public static void main(String[] args) {SpringApplication.run(MybatisPlusExeApplication.class, args);}}
@SpringBootTest
public class MyBatisPlusTest {@Autowiredprivate UserMapper userMapper;@Testpublic void testSelectList() {//通过条件构造器查询一个list集合，若没有条件，则可以设置null为参数List<User> list = userMapper.selectList(null);list.forEach(System.out::println);}@Testpublic void testInsert() {//实现新增用户信息//INSERT INTO user ( id, name, age, email ) VALUES ( ?, ?, ?, ? )User user = new User();user.setName("张三");user.setAge(23);user.setEmail("zhangsan@qq.com");int insert = userMapper.insert(user);System.out.println(insert);System.out.println("id:" + user.getId());}@Testpublic void testDelete() {//通过id删除用户信息//DELETE FROM user WHERE id=?
// int result = userMapper.deleteById(1860660370114965506L);
// System.out.println("result:" + result);//根据map集合中所设置的条件删除用户信息//DELETE FROM user WHERE name = ? AND age = ?
// HashMap<String, Object> map = new HashMap<>();
// map.put("name","张三");
// map.put("age",23);
// int result = userMapper.deleteByMap(map);
// System.out.println("result:" + result);//通过多个id实现批量删除//DELETE FROM user WHERE id IN ( ? , ? , ? )List<Long> list = Arrays.asList(1L, 2L, 3L);int result = userMapper.deleteBatchIds(list);System.out.println("result" + result);}@Testpublic void testUpdate(){//修改用户信息//UPDATE user SET name=?, email=? WHERE id=?User user = new User();user.setId(4L);user.setName("李四");user.setEmail("zhangsan@qq.com");int result = userMapper.updateById(user);System.out.println("result"+result);}@Testpublic void testSelect(){//SELECT id,name,age,email FROM user WHERE id=?//通过id查询用户信息/*User user = userMapper.selectById(1L);System.out.println(user);*///根据多个id查询多个用户信息//SELECT id,name,age,email FROM user WHERE id IN ( ? , ? , ? )
// List<Long> list = Arrays.asList(1L, 2L, 3L);
// List<User> users = userMapper.selectBatchIds(list);
// users.forEach(System.out::println);//根据map集合中的条件查询用户信息//SELECT id,name,age,email FROM user WHERE name = ? AND age = ?
// HashMap<String, Object> map = new HashMap<>();
// map.put("name", "Jack");
// map.put("age", 20);
// List<User> list = userMapper.selectByMap(map);
// list.forEach(System.out::println);//查询所有数据//SELECT id,name,age,email FROM userList<User> users = userMapper.selectList(null);users.forEach(System.out::println);}
}
加日志
mybatis-plus:configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
自定义功能
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.wang.mybatisplusexe.mapper.UserMapper"><!--Map<String,Object> selectMapById(Long id);--><select id="selectMapById" resultType="map">select id,name,age,email from user where id=#{id}</select>
</mapper>
package com.wang.mybatisplusexe.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.wang.mybatisplusexe.pojo.User;
import org.springframework.stereotype.Repository;import java.util.Map;@Repository
public interface UserMapper extends BaseMapper<User> {/*** 根据id查询用户信息为map集合*/Map<String,Object> selectMapById(Long id);
}
通用Service接口
package com.wang.mybatisplusexe.service;import com.baomidou.mybatisplus.extension.service.IService;
import com.wang.mybatisplusexe.pojo.User;public interface UserService extends IService<User> {}
package com.wang.mybatisplusexe.service.impl;import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.wang.mybatisplusexe.mapper.UserMapper;
import com.wang.mybatisplusexe.pojo.User;
import com.wang.mybatisplusexe.service.UserService;
import org.springframework.stereotype.Service;@Service
public class UserServiceImpl extends ServiceImpl<UserMapper,User> implements UserService {
}
<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.wang.mybatisplusexe.mapper.UserMapper">
<!--Map<String,Object> selectMapById(Long id);-->
<select id="selectMapById" resultType="map">select id,name,age,email from user where id=#{id}
</select>
</mapper>
@SpringBootTest
public class MyBatisPlusServiceTest {@Autowiredprivate UserService userService;@Testpublic void testGetCount(){//查询总记录数//SELECT COUNT( * ) FROM userlong count = userService.count();System.out.println(count);}@Testpublic void testInsertMore(){//批量添加//INSERT INTO user ( id, name, age ) VALUES ( ?, ?, ? )ArrayList<User> list = new ArrayList<>();for(int i=0;i<=10;i++){User user = new User();user.setName("wang"+i);user.setAge(20+i);list.add(user);}boolean b = userService.saveBatch(list);System.out.println(b);}
}
常用注解
@Data
//设置实体类所对应的表名
@TableName("t_user")
public class User {private Long id;private String name;private Integer age;private String email;
}
# 设置MyBatis-Plus的全局配置
global-config:db-config:# 设置实体类所在的表的统一前缀table-prefix: t_
@Data
//设置实体类所对应的表名
//@TableName("t_user")
public class User {//将属性所对应的字段指定为主键//@TableId注解的value属性用于指定主键的字段//@TableId注解的type属性设置主键生成策略@TableId(value = "uid",type = IdType.AUTO)private Long id;//指定属性所对应的字段名@TableField("user_name")private String name;private Integer age;private String email;@TableLogicprivate Integer isDeleted;
}
# 设置统一的主键生成策略
id-type: auto
雪花算法
条件构造器
QueryWrapper
@SpringBootTest
public class MyBatisPlusWrapperTest {@Autowiredprivate UserMapper userMapper;@Testpublic void test01(){//查询用户名包含a，年龄在20到30之间，邮箱信息不为null的用户信息//SELECT uid AS id,user_name AS name,age,email,is_deleted// FROM t_user WHERE is_deleted=0// AND (user_name LIKE ? AND age BETWEEN ?// AND ? AND email IS NOT NULL)QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.like("user_name","a").between("age",20,30).isNotNull("email");List<User> list = userMapper.selectList(queryWrapper);list.forEach(System.out::println);}
}
@Test
public void test02(){//查询用户信息，按照年龄的降序排序，若年龄相同，则按照id升序排序//SELECT uid AS id,user_name AS name,age,email,is_deleted//FROM t_user WHERE is_deleted=0 ORDER BY age DESC,uid ASCQueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.orderByDesc("age").orderByAsc("uid");List<User> list = userMapper.selectList(queryWrapper);list.forEach(System.out::println);
}
@Test
public void test03(){//删除邮箱地址为null的用户信息//UPDATE t_user SET is_deleted=1//WHERE is_deleted=0 AND (email IS NULL)QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.isNull("email");int result = userMapper.delete(queryWrapper);System.out.println("result"+result);
}
@Test
public void test04(){//将（年龄大于20并且用户名中包含有a）或邮箱为null的用户信息修改//UPDATE t_user SET user_name=?, email=? WHERE is_deleted=0// AND (age > ? AND user_name LIKE ? OR email IS NULL)QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.gt("age",20).like("user_name","a").or().isNull("email");User user=new User();user.setName("小明");user.setEmail("xiaoming@qq.com");int result = userMapper.update(user, queryWrapper);System.out.println("result"+result);
}
@Test
public void test05() {//将用户名中包含有a并且（年龄大于20或邮箱为null）的用户信息修改//lambda中的条件优先执行//UPDATE t_user SET user_name=?, email=? WHERE is_deleted=0//AND (user_name LIKE ? AND (age > ? OR email IS NULL))QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.like("user_name", "a").and(i->i.gt("age", 20).or().isNull("email"));User user = new User();user.setName("小红");user.setEmail("xiaohong@qq.com");int result = userMapper.update(user, queryWrapper);System.out.println("result" + result);
}
@Test
public void test06(){//查询用户的用户名、年龄、邮箱信息//SELECT user_name,age,email FROM t_user WHERE is_deleted=0QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.select("user_name","age","email");List<Map<String, Object>> maps = userMapper.selectMaps(queryWrapper);maps.forEach(System.out::println);
}
@Test
public void test07() {//查询id小于等于100的用户信息//SELECT uid AS id,user_name AS name,age,email,is_deleted// FROM t_user WHERE is_deleted=0// AND (uid IN (select uid from t_user where uid<=100))QueryWrapper<User> queryWrapper = new QueryWrapper<>();queryWrapper.inSql("uid", "select uid from t_user where uid<=100");List<User> list = userMapper.selectList(queryWrapper);list.forEach(System.out::println);
}
UpdateWrapper
@Test
public void test08(){//将用户名中包含有a并且（年龄大于20或邮箱为null）的用户信息修改//UPDATE t_user SET user_name=?,email=? //WHERE is_deleted=0 //AND (user_name LIKE ? AND (age > ? OR email IS NULL))UpdateWrapper<User> updateWrapper=new UpdateWrapper<>();updateWrapper.like("user_name", "a").and(e->e.gt("age",20).or().isNull("email"));updateWrapper.set("user_name","小黑").set("email","xiaohei@qq.com");int result = userMapper.update(null, updateWrapper);System.out.println("result" + result);
}
condition
@Test
public void test09(){// SELECT uid AS id,user_name AS name,age,email,is_deleted// FROM t_user WHERE is_deleted=0 AND (age >= ? AND age <= ?)String userName="";Integer ageBegin=20;Integer ageEnd=30;QueryWrapper<User> queryWrapper=new QueryWrapper<>();if(StringUtils.isNotBlank(userName)){//isNotBlank判断某个字符串是否不为空字符串、不为null、不为空白符queryWrapper.like("user_name",userName);}if(ageBegin!=null){queryWrapper.ge("age",ageBegin);}if(ageEnd!=null){queryWrapper.le("age",ageEnd);}List<User> list = userMapper.selectList(queryWrapper);list.forEach(System.out::println);
}
@Test
public void test10(){//SELECT uid AS id,user_name AS name,age,email,is_deleted //FROM t_user WHERE is_deleted=0 AND (user_name LIKE ?)String username="a";Integer ageBegin=null;Integer ageEnd=null;QueryWrapper<User> queryWrapper=new QueryWrapper<>();queryWrapper.like(StringUtils.isNotBlank(username),"user_name",username).ge(ageBegin!=null,"age",ageBegin).le(ageEnd!=null,"age",ageEnd);List<User> list = userMapper.selectList(queryWrapper);list.forEach(System.out::println);
}
lambdaQueryWrapper
@Test
public void test11(){String username="a";Integer ageBegin=null;Integer ageEnd=30;LambdaQueryWrapper<User> queryWrapper=new LambdaQueryWrapper<>();queryWrapper.like(StringUtils.isNotBlank(username),User::getName,username).ge(ageBegin!=null,User::getAge,ageBegin).le(ageEnd!=null,User::getAge,ageEnd);List<User> list = userMapper.selectList(queryWrapper);list.forEach(System.out::println);
}
lambdaUpdateWrapper
@Test
public void test12(){//将用户名中包含有a并且（年龄大于20或邮箱为null）的用户信息修改//UPDATE t_user SET user_name=?,email=?//WHERE is_deleted=0//AND (user_name LIKE ? AND (age > ? OR email IS NULL))LambdaUpdateWrapper<User> updateWrapper=new LambdaUpdateWrapper<>();updateWrapper.like(User::getName, "a").and(e->e.gt(User::getAge,20).or().isNull(User::getEmail));updateWrapper.set(User::getName,"小黑").set(User::getEmail,"xiaohei@qq.com");int result = userMapper.update(null, updateWrapper);System.out.println("result" + result);
}
插件
分页插件
配置类
@Configuration
//扫描mapper接口所在的包
@MapperScan("com.wang.mybatisplusexe.mapper")
public class MyBatisPlusConfig {@Beanpublic MybatisPlusInterceptor mybatisPlusInterceptor() {MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));return interceptor;}
}
测试
@SpringBootTest
public class MyBatisPlusPluginsTest {@Autowiredprivate UserMapper userMapper;@Testpublic void testPage() {//SELECT uid AS id,user_name AS name,age,email,is_deleted//FROM t_user WHERE is_deleted=0 LIMIT ?Page<User> page = new Page<>(1, 3);userMapper.selectPage(page, null);System.out.println(page);}
}
@Test
public void testPage() {//SELECT uid AS id,user_name AS name,age,email,is_deleted//FROM t_user WHERE is_deleted=0 LIMIT ?Page<User> page = new Page<>(1, 3);userMapper.selectPage(page, null);System.out.println(page.getRecords());System.out.println(page.getPages());System.out.println(page.getTotal());System.out.println(page.hasNext());System.out.println(page.hasPrevious());
}
自定义分页功能
@Repository
public interface UserMapper extends BaseMapper<User> {/*** 根据id查询用户信息为map集合*/Map<String, Object> selectMapById(Long id);/*** 根据年龄查询用户并分页* @param page MyBatis-Plus所提供的分页对象，必须位于第一个参数的位置* @param age* @return*/Page<User> selectPageVo(@Param("page") Page<User> page, @Param("age") Integer age);
}
# 配置类型别名所对应的包
type-aliases-package: com.wang.mybatisplusexe.pojo
<!-- Page<User> selectPageVo(@Param("page") Page<User> page, @Param("age") Integer age);-->
<select id="selectPageVo" resultType="com.wang.mybatisplusexe.pojo.User">select uid, user_name, age, emailfrom t_userwhere age > #{age}
</select>
@Test
public void testPageVo(){//select uid, user_name, age, email from t_user where age > ? LIMIT ?Page<User> page = new Page<>(1, 3);userMapper.selectPageVo(page,20);System.out.println(page.getRecords());System.out.println(page.getPages());System.out.println(page.getTotal());System.out.println(page.hasNext());System.out.println(page.hasPrevious());
}
乐观锁插件
@Configuration
//扫描mapper接口所在的包
@MapperScan("com.wang.mybatisplusexe.mapper")
public class MyBatisPlusConfig {@Beanpublic MybatisPlusInterceptor mybatisPlusInterceptor() {MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));//乐观锁插件interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());return interceptor;}
}
@Repository
public interface ProductMapper extends BaseMapper<Product> {
}
@Data
public class Product {private Long id;private String name;private Integer price;@Version//标识乐观锁版本号字段private Integer version;
}
@Test
public void testProduct(){//小李查询商品价格Product productLi=productMapper.selectById(1);System.out.println("小李查询的商品价格："+productLi.getPrice());//小王查询商品价格Product productWang = productMapper.selectById(1);System.out.println("小王查询的商品价格"+productWang.getPrice());//小李将商品价格+50productLi.setPrice(productLi.getPrice()+50);productMapper.updateById(productLi);//小王将商品价格-30productWang.setPrice(productWang.getPrice()-30);int result = productMapper.updateById(productWang);if(result==0){//操作失败，重试Product productNew = productMapper.selectById(1);productNew.setPrice(productNew.getPrice()-30);productMapper.updateById(productNew);}//老板查询商品价格Product productBoss = productMapper.selectById(1);System.out.println("老板查询的商品价格"+productBoss.getPrice());
}
通用枚举
# 扫描通用枚举的包
type-enums-package: com.wang.mybatisplusexe.enums
@Getter
public enum SexEnum {MALE(1, "男"),FEMALE(2, "女");@EnumValue//将注解所标识的属性的值存储到数据库中private Integer sex;private String sexName;SexEnum(Integer sex, String sexName) {this.sex = sex;this.sexName = sexName;}
}
@SpringBootTest
public class MyBatisPlusEnumTest {@Autowiredprivate UserMapper userMapper;@Testpublic void test(){User user = new User();user.setName("admin");user.setAge(33);user.setSex(SexEnum.MALE);int result = userMapper.insert(user);System.out.println("result:"+result);}
}
代码生成器
<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-generator</artifactId><version>3.5.9</version>
</dependency>
<dependency><groupId>org.freemarker</groupId><artifactId>freemarker</artifactId><version>2.3.32</version>
</dependency>
public static void main(String[] args) {FastAutoGenerator.create("jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=false","root","20050606a").globalConfig(builder -> builder.author("wang").outputDir("D://code//text").commentDate("2024-11-27")).packageConfig(builder -> builder.parent("com.wang").entity("entity").mapper("mapper").service("service").serviceImpl("service.impl").xml("mapper.xml")).strategyConfig(builder -> builder.entityBuilder().enableLombok()).templateEngine(new FreemarkerTemplateEngine()).execute();
}
多数据源
<dependency><groupId>com.baomidou</groupId><artifactId>dynamic-datasource-spring-boot-starter</artifactId><version>3.5.1</version>
</dependency>
spring:# 配置数据源信息datasource:dynamic:# 设置默认的数据源或者数据源组，默认值即为masterprimary: master# 严格匹配数据源，默认false.true未匹配到指定数据源时抛异常，false使用默认数据源strict: falsedatasource:master:url: jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=falsedriver-class-name: com.mysql.cj.jdbc.Driverusername: rootpassword: 20050606aslave_1:url: jdbc:mysql://localhost:3306/mybatis_plus_1?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=falsedriver-class-name: com.mysql.cj.jdbc.Driverusername: rootpassword: 20050606a
@Service
@DS("slave_1")
public class ProductServiceImpl extends ServiceImpl<ProductMapper, Product> implements ProductService {
}
@Service
@DS("master")
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {
}
@SpringBootTest
class MybatisPlusDatasourceApplicationTests {@Autowiredprivate ProductService productService;@Autowiredprivate UserService userService;@Testpublic void test() {System.out.println(productService.getById(1));System.out.println(userService.getById(1));}}
MyBatisX插件
MyBatis-Plus为我们提供了强大的mapper和service模板，能够大大的提高开发效率。
但是在真正开发过程中，MyBatis-Plus并不能为我们解决所有问题，例如一些复杂的SQL，多表联查，我们就需要自己去编写代码和SQL语句，我们该如何快速的解决这个问题呢，这个时候可以使用MyBatisX插件。
MyBatisX一款基于IDEA的快速开发插件，为效率而生。
https://baomidou.com/guides/mybatis-x/
