MybatisPlus
1. 什么是MybatisPlus
MyBatis-Plus (opens new window)（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。
2.MybatisPlus预先配置
2.1 导入依赖
SpringBoot2版本
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| <dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.5.4</version>
</dependency>
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2.x 配置yaml
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| mybatis-plus:
mapper-locations: classpath*:/mapper/**/*.xml
type-aliases-package: com.itheima.mp.domain.po
global-config:
db-config:
id-type: auto
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2.x 继承BaseMapper接口
在需要使用MybatisPlus的Mapper接口中继承BaseMapper
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| public interface UserMapper extends BaseMapper<User> {
}
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3.使用MybatisPlus
1.基础查询
使用BaseMapper中自带的单表查询语句
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| @Test
void testInsert() {
User user = new User();
user.setId(5L);
user.setUsername("Lucy");
user.setPassword("123");
user.setPhone("18688990011");
user.setBalance(200);
user.setInfo("{\"age\": 24, \"intro\": \"英文老师\", \"gender\": \"female\"}");
user.setCreateTime(LocalDateTime.now());
user.setUpdateTime(LocalDateTime.now());
userMapper.insert(user);
}
@Test
void testDelete(){
int i = userMapper.deleteById(5L);
System.out.println("删除受影响行"+i);
}
@Test
void testSelect(){
User user = userMapper.selectById(4L);
System.out.println(user);
}
@Test
void testUpdate(){
User user = new User();
user.setUpdateTime(LocalDateTime.now());
user.setUsername("Lucy");
user.setId(5L);
int i = userMapper.updateById(user);
System.out.println("更新受影响行"+i);
}
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x.处理对象属性
x.1 创建属性对象POJO类
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| package com.itheima.mp.domain.po;
import lombok.Data;
@Data
public class UserInfo {
private Integer age;
private String intro;
private String gender;
}
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x.2 这实体类中添加注解
属性
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| @TableField(typeHandler = JacksonTypeHandler.class)
private UserInfo info;
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类
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| @Data
@TableName(value = "tb_user",autoResultMap = true)
public class User {
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x. 使用MybatisPlusInterceptor分页插件
x.1 编写拦截器
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| package com.itheima.mp.config;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MybatisPlusConfig {
@Bean
public MybatisPlusInterceptor mybatisPlusInterceptor() {
MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
PaginationInnerInterceptor paginationInnerInterceptor = new PaginationInnerInterceptor();
paginationInnerInterceptor.setMaxLimit(1000L);
interceptor.addInnerInterceptor(paginationInnerInterceptor);
return interceptor;
}
}
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x.2 使用分页插件
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| @Test
void pageSelect(){
Page<User> page = new Page<>(2,3);
page.addOrder(new OrderItem("balance",false))
.addOrder(new OrderItem("id",true));
Page<User> pageResult = userService.page(page);
System.out.println("total:"+ pageResult.getTotal());
System.out.println("pages:"+ pageResult.getPages());
List<User> records = pageResult.getRecords();
records.forEach(System.out::println);
}
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