MyBatis-Plus之面向Mapper编程
Posted 程序猿老高
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了MyBatis-Plus之面向Mapper编程相关的知识，希望对你有一定的参考价值。
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。
官网：https://mp.baomidou.com/
MyBatis-Plus技术提供了面向Service和面向Mapper两种编程途径，这里给大家介绍一下如何使用Mapper实现数据增删改查和分页：
1、表与数据
CREATE TABLE `student` (
`sno` int PRIMARY KEY AUTO_INCREMENT,
`sname` varchar(255) NOT NULL,
`ssex` varchar(1) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT '1',
`birthday` timestamp(6) NULL DEFAULT NULL,
`pass` varchar(255) DEFAULT NULL,
`mno` int DEFAULT NULL,
`delFlg` int DEFAULT '1' COMMENT '1：不删除；0：删除状态'
)
INSERT INTO `student` VALUES (1, 'Tom', '1', '2020-07-31 00:00:00.000000', '111111', 1, 0);
INSERT INTO `student` VALUES (2, 'Jack', '1', '2020-07-31 00:00:00.000000', '111111', 2, 0);
INSERT INTO `student` VALUES (3, '张三', '1', '2020-08-03 09:06:38.000000', '111111', 5, 1);
INSERT INTO `student` VALUES (4, '张伟', '1', '2020-08-03 09:06:38.000000', '111111', 6, 1);
2、Maven依赖
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.3.9</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.3.9</version>
</dependency>
<dependency>
<groupId>com.zaxxer</groupId>
<artifactId>HikariCP</artifactId>
<version>3.4.5</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.30</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus</artifactId>
<version>3.4.1</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.6.4</version>
</dependency>
3、Log4j配置
log4j.rootLogger=debug,console,file
#输出到控制台
log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=%-5p %dMM-dd HH:mm:ss,SSS %m (%F:%L) \\n
#输出到文件
log4j.appender.file=org.apache.log4j.FileAppender
log4j.appender.file.File=D:\\\\log4j.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%-5p %dMM-dd HH:mm:ss,SSS %m (%F:%L) \\n
#SQL语句
log4j.logger.com.mybatis=DEBUG
log4j.logger.com.mybatis.common.jdbc.SimpleDataSource=DEBUG
log4j.logger.com.mybatis.common.jdbc.ScriptRunner=DEBUG
log4j.logger.com.mybatis.sqlmap.engine.impl.SqlMapClientDelegate=DEBUG
log4j.logger.java.sql.Connection=DEBUG
log4j.logger.java.sql.Statement=DEBUG
log4j.logger.java.sql.PreparedStatement=DEBUG
4、MyBatis全局配置
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
</configuration>
5、Spring配置
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:mybatis-spring="http://mybatis.org/schema/mybatis-spring"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd http://mybatis.org/schema/mybatis-spring http://mybatis.org/schema/mybatis-spring.xsd">
<!--数据源配置-->
<bean id="dataSource" class="com.zaxxer.hikari.HikariDataSource" lazy-init="false" destroy-method="close">
<property name="driverClassName" value="com.mysql.cj.jdbc.Driver"></property>
<property name="jdbcUrl" value="jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf8"></property>
<property name="username" value="root"></property>
<property name="password" value="root"></property>
</bean>
<!--MyBatis配置-->
<bean class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean">
<!--数据源注入-->
<property name="dataSource" ref="dataSource"/>
<!--加载MyBatis配置文件-->
<property name="configLocation" value="mybatis-config.xml"/>
<!--插件-->
<property name="plugins">
<!--PageHelper-->
<!--<bean class="com.github.pagehelper.PageInterceptor"></bean>-->
<!--MyBatisPlus分页插件-->
<bean class="com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor">
<property name="interceptors">
<list>
<bean class="com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor">
<!--数据库类型-->
<constructor-arg name="dbType" value="MYSQL"></constructor-arg>
</bean>
</list>
</property>
</bean>
</property>
</bean>
<!--接口扫描-->
<mybatis-spring:scan base-package="com.soft.*.dao"></mybatis-spring:scan>
</beans>
6、实体类
public class Student
@TableId(value="sno", type = IdType.AUTO)
private String sno;
private String sname;
private String ssex;
private String birthday;
private String pass;
private String mno;
@TableField("delFlg")
private String delFlg;//默认情况下，MyBatisPlus会将驼峰命名的变量变为下划线间隔的字段，除非使用TableField注解手动指定字段名
// 省略set/get方法
7、Dao接口
package com.soft.student.dao;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.soft.vo.Student;
public interface IStudentDao extends BaseMapper<Student>
8、测试
8.1、增
package com.soft.test;
import com.soft.student.dao.IStudentDao;
import com.soft.vo.Student;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class InsertTest
public static void main(String[] args)
ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("application.xml");
IStudentDao studentDao = applicationContext.getBean(IStudentDao.class);
//添加（主键自增，在实体类上加上@TableId既可以 @TableId(value = "id", type = IdType.AUTO)）
Student student = new Student();
student.setSname("高焕杰");
student.setSsex("1");
student.setBirthday("2022-06-08");
student.setPass("123456");
student.setMno("5");
student.setDelFlg("1");
int rusult = studentDao.insert(student);
System.out.println(rusult);
8.2、删
package com.soft.test;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.soft.student.dao.IStudentDao;
import com.soft.vo.Student;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
public class DeleteTest
public static void main(String[] args)
ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("application.xml");
IStudentDao studentDao = applicationContext.getBean(IStudentDao.class);
//根据主键ID删除
result = studentDao.deleteById(10);
System.out.println("result = " + result);
System.out.println("@@@@@@@@@@@@@@@@@");
//根据id集合批量删除
result = studentDao.deleteBatchIds(Arrays.asList(4,5));//idList 主键ID列表(不能为 null 以及 empty)
System.out.println("result = " + result);
System.out.println("@@@@@@@@@@@@@@@@@");
//根据 entity 条件，删除记录
Student student = new Student();
student.setSname("张三");
student.setSsex("1");
//将实体对象进行包装，包装为操作条件
QueryWrapper<Student> wrapper = new QueryWrapper<>(student);
int result = studentDao.delete(wrapper);
System.out.println("result = " + result);
System.out.println("@@@@@@@@@@@@@@@@@");
//根据条件模糊删除
QueryWrapper<Student> wrapper = new QueryWrapper<>();
wrapper.like("sname","四");
result = studentDao.delete(wrapper);
System.out.println(result);
System.out.println("@@@@@@@@@@@@@@@@@");
//根据 columnMap 条件，删除记录
Map<String, Object> columnMap = new HashMap<>();
columnMap.put("sname","张飞");
columnMap.put("ssex","1");
//将columnMap中的元素设置为删除的条件，多个之间为and关系
result = studentDao.deleteByMap(columnMap);
System.out.println("result = " + result);
8.3、改
package com.soft.test;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper;
import com.soft.student.dao.IStudentDao;
import com.soft.vo.Student;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class UpdateTest
public static void main(String[] args)
ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("application.xml");
IStudentDao studentDao = applicationContext.getBean(IStudentDao.class);
//根据 ID 修改
Student student = new Student();
student.setSno("6");//主键
student.setSname("狗蛋儿");//更新的字段
//根据id更新，更新不为null的字段
studentDao.updateById(student);
System.out.println("##################");
//更新字段
student = new Student();
student.setSname("张老三");
//更新条件
QueryWrapper<Student> queryWrapper = new QueryWrapper<Student>();
queryWrapper.eq("sno", 8);
//更新操作
int result = studentDao.update(student, queryWrapper);
System.out.println("result = " + result);
System.out.println("##################");
//更新条件及字段
UpdateWrapper<Student> updateWrapper = new UpdateWrapper<>();
updateWrapper.eq("sno", 11).set("sname", "李老四");
//更新操作
result = studentDao.update(null, updateWrapper);
System.out.println("result = " + result);
8.4、查
package com.soft.test;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.soft.studentMybatis-plus异常解决之--org.apache.ibatis.binding.BindingException
Mybatis-Plus通用Mapper CRUD之insert(附带视频教程)
基于Spring+SpringMVC+MyBatis-Plus开发书评网图书详情模块开发之获取图书信息并展示