SpringBoot+mybatis plus 框架搭建

1、引入引用

 

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<?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 https://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>2.6.2</version>         <relativePath/> <!-- lookup parent from repository -->     </parent>     <groupId>com.ymn</groupId>     <artifactId>mybatis003</artifactId>     <version>0.0.1-SNAPSHOT</version>     <name>mybatis003</name>     <description>mybatis003</description>     <properties>         <java.version>1.8</java.version>     </properties>     <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>           <dependency>             <groupId>com.baomidou</groupId>             <artifactId>mybatis-plus-boot-starter</artifactId>             <version>3.4.3.4</version>         </dependency>         <!-- 导入mysql -->         <dependency>             <groupId>mysql</groupId>             <artifactId>mysql-connector-java</artifactId>             <scope>runtime</scope>         </dependency>         <dependency>             <groupId>com.h2database</groupId>             <artifactId>h2</artifactId>             <scope>runtime</scope>         </dependency>         <dependency>             <groupId>org.projectlombok</groupId>             <artifactId>lombok</artifactId>             <version>RELEASE</version>             <scope>compile</scope>         </dependency>         <dependency>             <groupId>junit</groupId>             <artifactId>junit</artifactId>             <version>4.13.1</version>             <scope>test</scope>         </dependency>     </dependencies>       <build>         <plugins>             <plugin>                 <groupId>org.springframework.boot</groupId>                 <artifactId>spring-boot-maven-plugin</artifactId>             </plugin>         </plugins>     </build>   </project>

　　2、配置数据库连接地址

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# DataSource Config server:   port: 8099 spring:   datasource:     driver-class-name: com.mysql.cj.jdbc.Driver     url: jdbc:mysql://localhost:3306/mybatisplus02?autoRe connect=true&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=CONVERT_TO_NULL&useSSL=false&nullCatalogMeansCurrent=true     username: root     password: 545456546546

　3、创建mapper

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@Component public interface UserMapper  extends BaseMapper<User> {     }

4、创建service访问

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@Component public interface UserMapper  extends BaseMapper<User> {     }

　　

5、单元测试测试

package com.ymn.mybatis003;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.ymn.mybatis003.entitys.User;
import com.ymn.mybatis003.mappers.UserMapper;
import com.ymn.mybatis003.services.UserService;
import org.junit.Assert;
import org.junit.jupiter.api.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.util.List;
//有了@RunWith(SpringRunner.class)这些类才能实例化到spring容器中，自动注入才能生效，
@RunWith(SpringRunner.class)
@SpringBootTest
class Mybatis003ApplicationTests {

    @Autowired
    private UserMapper userMapper;

    @Autowired
    private UserService userService;

    @Test
    public void testSelect() {
        System.out.println(("----- selectAll method test ------"));
        List<User> userList = userMapper.selectList(null);
        //Assert.assertEquals(5, userList.size());
        userList.forEach(System.out::println);
        userList.get(0).setName("王五77");
        //Update name by id
        userMapper.updateById(userList.get(0));

        //query user by id
        User user = userMapper.selectById(4);
        System.out.println("编号为4的用户："+user.getName());

        //use wrapper query
        QueryWrapper<User>  queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("id",5);
        User user5 = userMapper.selectOne(queryWrapper);
        System.out.println("第五名用户");
        System.out.println(user5);

        //query count
        QueryWrapper<User> queryWrapper1 = new QueryWrapper<>();
        queryWrapper1.gt("age",10);
        Long count = userMapper.selectCount(queryWrapper1);
        System.out.println("大于10岁的用户数："+count);

        User user3 = userService.getById(1);
        System.out.println("使用service获取对象");
        System.out.println(user3);

        LambdaQueryWrapper<User> lamadaQueryWrapper = new LambdaQueryWrapper<>();
        lamadaQueryWrapper.eq(User::getId,9);
        User user9 = userService.getOne(lamadaQueryWrapper);
        System.out.println("第九个用户的名称："+user9.getName());

    }



}


6、sql语句