java——mybatis-plus随笔
网上参考总教程：https://www.quanxiaoha.com/mybatis-plus/mybatis-plus-tutorial.html
本地参考教程：https://www.cnblogs.com/xiaobaibailongma/p/17091309.html
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gitee参考教程：
springbootmybatisplus/pom.xml
配置文件：https://gitee.com/xiaobailongbailongma/springboot/blob/master/springbootmybatisplus/pom.xml
springbootmybatisplus/src/main/resources/application.properties
配置文件：https://gitee.com/xiaobailongbailongma/springboot/blob/master/springbootmybatisplus/src/main/resources/application.properties
springbootmybatisplus/src/main/java/org/example/mapper/UserMapper.java
配置文件：https://gitee.com/xiaobailongbailongma/springboot/blob/master/springbootmybatisplus/src/main/java/org/example/mapper/UserMapper.java
springbootmybatisplus/src/main/java/org/example/Entity/MyUser.java
配置文件：https://gitee.com/xiaobailongbailongma/springboot/blob/master/springbootmybatisplus/src/main/java/org/example/Entity/MyUser.java
springbootmybatisplus/src/main/java/org/example/service/MyUserService.java
配置文件：https://gitee.com/xiaobailongbailongma/springboot/blob/master/springbootmybatisplus/src/main/java/org/example/service/MyUserService.java
springbootmybatisplus/src/main/java/org/example/service/Impl/MyUserServiceImpl.java
配置文件：https://gitee.com/xiaobailongbailongma/springboot/blob/master/springbootmybatisplus/src/main/java/org/example/service/Impl/MyUserServiceImpl.java
springbootmybatisplus/src/main/java/org/example/controller/MyUserController.java
配置文件：https://gitee.com/xiaobailongbailongma/springboot/blob/master/springbootmybatisplus/src/main/java/org/example/controller/MyUserController.java
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spring boot集成mybatis-plus——新建工程与查询所有数据
第一步引入依赖：
<?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>
<groupId>org.example</groupId>
<artifactId>springbootmybatisplus</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.4.5</version>
<relativePath/>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.5.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
</dependencies>
</project>
第二步：设置数据库信息：
spring.datasource.username=root spring.datasource.password=123456 spring.datasource.url=jdbc:mysql://localhost:3306/mysql8?characterEncoding=utf8 spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
数据库信息
第三步：创建实体类：
package org.example.Entity;
import com.baomidou.mybatisplus.annotation.TableName;
@TableName("users") //不一致时，需要映射
public class MyUser
{
private int id;
private String name;
private int age;
public int getId()
{
return id;
}
public void setId(int id)
{
this.id = id;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public int getAge()
{
return age;
}
public void setAge(int age)
{
this.age = age;
}
@Override
public String toString()
{
return "MyUser{" +
"id=" + id +
", name='" + name + '\'' +
", age=" + age +
'}';
}
}
第四步：常见mapper文件：
package org.example.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Mapper;
import org.example.Entity.MyUser;
@Mapper
public interface UserMapper extends BaseMapper<MyUser>
{
//所有的CRUD都已经完成
//不需要像以前一样配置一大堆文件：pojo-dao（连接mybatis，配置mapper.xml文件）==>service-controller
}
第五步：创建业务层以及实现接口：
package org.example.service;
import org.example.Entity.MyUser;
import java.util.List;
public interface MyUserService
{
// 查询所有用户
List<MyUser> findAll();
}
package org.example.service.Impl;
import org.example.Entity.MyUser;
import org.example.mapper.UserMapper;
import org.example.service.MyUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class MyUserServiceImpl implements MyUserService
{
//继承了BaseMapper所有的方法，可以编写自己的扩展方法
@Autowired
private UserMapper userMapper;
@Override
public List<MyUser> findAll()
{
return userMapper.selectList(null);
}
}
第六步：控制器接口：
package org.example.controller;
import org.example.Entity.MyUser;
import org.example.service.MyUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
@RestController
public class MyUserController
{
@Autowired
private MyUserService myUserService;
@GetMapping(value = "/1")
public List<MyUser> home1()
{
// 查询所有用户信息
List<MyUser> users = myUserService.findAll();
for (MyUser user : users)
{
System.out.println(user.getId()+" "+user.getName()+" "+user.getAge());
}
return users;
}
}
第七步：运行主程序：
package org.example;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("org.example.mapper")
public class HelloWorldApplication
{
public static void main(String[] args)
{
SpringApplication.run(HelloWorldApplication.class, args);
}
}
实现如下：
