mybaits-plus学习笔记整合
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文章目录
准备工作
创建数据库
创建数据库以及表
创建数据库并设置字符集为utf-8:
CREATE DATABASE `mp` CHARACTER SET 'utf8' COLLATE 'utf8_general_ci';
创建表和测试数据:
--
-- 表的结构 `tb_user`
--
CREATE TABLE IF NOT EXISTS `tb_user` (
`id` bigint(20) NOT NULL COMMENT '主键ID',
`user_name` varchar(20) NOT NULL COMMENT '用户名',
`password` varchar(20) NOT NULL COMMENT '密码',
`name` varchar(30) DEFAULT NULL COMMENT '姓名',
`age` int(11) DEFAULT NULL COMMENT '年龄',
`email` varchar(50) DEFAULT NULL COMMENT '邮箱',
`birthday` datetime DEFAULT NULL
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
--
-- 表中的数据 `tb_user`
--
INSERT INTO `tb_user` (`id`, `user_name`, `password`, `name`, `age`, `email`, `birthday`) VALUES
(1, 'zhangsan', '123456', '张三', 18, 'test1@yyl.cn', '2022-03-09 00:00:00'),
(2, 'lisi', '123456', '李四', 20, 'test2@yyl.cn', '2022-03-09 00:00:00'),
(3, 'wangwu', '123456', '王五', 28, 'test3@yyl.cn', '2022-03-09 00:00:00'),
(4, 'zhaoliu', '123456', '赵六', 21, 'test4@yyl.cn', '2022-03-09 00:00:00'),
(5, 'sunqi', '123456', '孙七', 24, 'test5@yyl.cn', '2022-03-09 00:00:00');
工程搭建
工程结构
创建工程
创建maven工程,分别填写GroupId ArtifactId和Version,如下:
<groupId>cn.yyl.mp</groupId>
<artifactId>yyl-mp-springboot</artifactId>
<version>1.0-SNAPSHOT</version>
导入依赖
导入maven依赖,由于本例采用Spring boot技术,使用mybatis-plus-boot-starter能与其便捷集成: 版本规划:
Spring boot: 2.1.3.RELEASE
mybatis-plus: 3.1.0
pom文件如下:
<?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 http://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>2.1.3.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!--简化代码的工具包-->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<!--mybatis-plus的springboot支持-->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.1.0</version>
</dependency>
<!--mysql驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.11</version>
</dependency>
</dependencies>
</project>
编写application.properties
spring.application.name = yyl-mp-springboot
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/mp?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&useSSL=false
spring.datasource.username=root
spring.datasource.password=root
# Logger Config
logging.level.root: debug
编写pojo
package cn.yyl.mp.pojo;
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 lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;
import java.time.LocalDateTime;
/**
* @author Administrator
* @version 1.0
**/
@Data
@ToString
@NoArgsConstructor
@AllArgsConstructor
@TableName("tb_user")
public class User
@TableId(value = "id",type= IdType.ID_WORKER)//指定主键的字段名
private Long id;
@TableField("user_name")//指定对应字段名
private String userName;
@TableField("PASSWORD")
private String password;
@TableField("NAME")
private String name;
@TableField("AGE")
private Integer age;
@TableField("EMAIL")
private String email;
@TableField("BIRTHDAY")
private LocalDateTime birthday;
注解说明:
lomlok:
@Data:lombok的注解,使用它可以省略getter/setter方法。
@NoArgsConstructor: 生成无参构造 方法
@AllArgsConstructor:生成所有参数构造 方法,参数顺序与属性定义顺序一致。
mybaits-plus:
@TableName:指定表名
@TableId:指定主键名
@TableField:指定列名
编写mapper
package cn.yyl.mp.mapper;
import cn.yyl.mp.pojo.User;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
/**
* Created by Administrator.
*/
public interface UserMapper extends BaseMapper<User>
该mapper类继承mybatisplus中的BaseMapper类
BaseMapper类中有一些常用的数据库查询方法,使用Base类之外的查询方法可以自己手动配置xml实现:
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//
package com.baomidou.mybatisplus.core.mapper;
import com.baomidou.mybatisplus.core.conditions.Wrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import java.io.Serializable;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import org.apache.ibatis.annotations.Param;
public interface BaseMapper<T>
int insert(T entity);
int deleteById(Serializable id);
int deleteByMap(@Param("cm") Map<String, Object> columnMap);
int delete(@Param("ew") Wrapper<T> wrapper);
int deleteBatchIds(@Param("coll") Collection<? extends Serializable> idList);
int updateById(@Param("et") T entity);
int update(@Param("et") T entity, @Param("ew") Wrapper<T> updateWrapper);
T selectById(Serializable id);
List<T> selectBatchIds(@Param("coll") Collection<? extends Serializable> idList);
List<T> selectByMap(@Param("cm") Map<String, Object> columnMap);
T selectOne(@Param("ew") Wrapper<T> queryWrapper);
Integer selectCount(@Param("ew") Wrapper<T> queryWrapper);
List<T> selectList(@Param("ew") Wrapper<T> queryWrapper);
List<Map<String, Object>> selectMaps(@Param("ew") Wrapper<T> queryWrapper);
List<Object> selectObjs(@Param("ew") Wrapper<T> queryWrapper);
IPage<T> selectPage(IPage<T> page, @Param("ew") Wrapper<T> queryWrapper);
IPage<Map<String, Object>> selectMapsPage(IPage<T> page, @Param("ew") Wrapper<T> queryWrapper);
编写启动类
package cn.yyl.mp;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
/**
* @author Administrator
* @version 1.0
**/
@SpringBootApplication
@MapperScan("cn.yyl.mp.mapper") //设置mapper接口的扫描包
public class MyApplication
public static void main(String[] args)
SpringApplication.run(MyApplication.class,args);
注解说明:
@SpringBootApplication springboot启动入口标识
@MapperScan("cn.yyl.mp.mapper") mapper接口的扫描包
测试
编写测试用例
编写UserMapper的测试用例 ,使用UserMapper查询用户列表。
在test下创建测试类,包名为 cn.yyl.mp。
package cn.itcast.mp;
import cn.itcast.mp.mapper.UserMapper;
import cn.itcast.mp.pojo.User;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Arrays;
import java.util.List;
/**
* @author Administrator
* @version 1.0
**/
@RunWith(SpringRunner.class)
@SpringBootTest
public class UserMapperTest
@Autowired
UserMapper userMapper;
x
@Test
public void testSelect()
//查询tb_user记录
List<User> users = userMapper.selectList(null);
System.out.println(users.toString());
运行测试
[
User(id=1, userName=zhangsan, password=123456, name=张三, age=18, email=test1@itcast.cn, birthday=2022-03-09T00:00),
User(id=2, userName=lisi, password=123456, name=李四, age=20, email=test2@itcast以上是关于mybaits-plus学习笔记整合的主要内容,如果未能解决你的问题,请参考以下文章