文章目录

1、简介

mybatisPlus在Springboot中的使用_spring

2、支持的数据库

mybatisPlus在Springboot中的使用_spring boot_02

3、框架

mybatisPlus在Springboot中的使用_spring boot_03

4、创建一个springboot项目

目录结构：

mybatisPlus在Springboot中的使用_用户信息_04

4.1 、pom文件中加入依赖

<!--         mybatisPlus的依赖-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.1</version>
        </dependency>

<!--        lombox的依赖-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

<!--        mysql的依赖-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

这里可能会出现的问题：编译打包不成功（修改版本）。
解决方法如下：

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>

        <!--在这里修改版本-->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-resources-plugin</artifactId>
            <version>2.4.3</version>
        </plugin>
        <!---->

    </plugins>
</build>

4.2、yml文件的配置

spring:
#  配置数据源信息
  datasource:
#    配置数据源类型
    type: com.zaxxer.hikari.HikariDataSource
#    配置连接数据库的各个信息
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/mybatis_plus?allowMultiQueries=true&characterEncoding=UTF-8&characterSetResults=UTF-8&zeroDateTimeBehavior=convertToNull&useSSL=false
    driver-class-name: com.mysql.cj.jdbc.Driver


server:
  port: 8383


mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

4.3 、数据库脚本

创建数据库和表

CREATE DATABASE `mybatis_plus` /*!40100 DEFAULT CHARACTER SET utf8mb4 */;
 use `mybatis_plus`;
 CREATE TABLE `user` ( 
 `id` bigint(20) NOT NULL COMMENT '主键ID',
 `name` varchar(30) DEFAULT NULL COMMENT '姓名',
 `age` int(11) DEFAULT NULL COMMENT '年龄', 
 `email` varchar(50) DEFAULT NULL COMMENT '邮箱',
  PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

表中插入数据

INSERT INTO user (id, name, age, email) VALUES 
(1, 'Jone', 18, 'test1@baomidou.com'), 
(2, 'Jack', 20, 'test2@baomidou.com'), 
(3, 'Tom', 28, 'test3@baomidou.com'), 
(4, 'Sandy', 21, 'test4@baomidou.com'), 
(5, 'Billie', 24, 'test5@baomidou.com');

4.4、实体类

public class User {

    private Long id;

    private String name;

    private Integer age;

    private String email;

}

4.5 、启动类添加包扫描

@SpringBootApplication
//扫描mapper接口所在的包
@MapperScan("com.zyz.mybatisplus.mapper")
public class MybatisplusApplication {

    public static void main(String[] args) {
        SpringApplication.run(MybatisplusApplication.class, args);
    }

}

4.6、 mapper包下的UserMapper接口

@Repository
public interface UserMapper extends BaseMapper<User> {

}

4.7、 测试mybatisplus

@SpringBootTest
public class MyBatisPlusTest {

    @Autowired
    private UserMapper userMapper;

//    @Test
//    public void testSelectList() {
//
//        List<User> list = userMapper.selectList(null);
//        list.forEach(System.out::println);
//
//    }

//    测试增加
    @Test
    public void testAdd(){
        //实现用户新增
        //INSERT INTO user ( id, name, age, email ) VALUES ( ?, ?, ?, ? )

        User user = new User();
//        user.setId(5L);
        user.setName("张三");
        user.setAge(23);
        user.setEmail("zhangsan@qq.com");
        int rs = userMapper.insert(user);
        System.out.println("测试结果："+rs);
        System.out.println(user.getId());
    }

    @Test
    public void testDelete(){
        /**
         *  1、根据id删除信息
         *    DELETE FROM user WHERE id=?
         */
        int rs = userMapper.deleteById(5L);
        System.out.println(rs);

        /**
         * 2、根据map集合中所设置的条件删除用户信息
         * DELETE FROM user WHERE name = ? AND age = ?
         */
//        HashMap<String, Object> map = new HashMap<>();
//        map.put("name","张三");
//        map.put("age",23);
//        int rs = userMapper.deleteByMap(map);
//        System.out.println(rs);

        /**
         *  通过多个id实现批量删除
         *  DELETE FROM user WHERE id IN ( ? , ? , ? )
         */
//        List<Long> list = Arrays.asList(1L,2L,3L);
//        int rs = userMapper.deleteBatchIds(list);
//        System.out.println(rs);

    }

    @Test
    public void testUpdate(){
        /**
         * 修改用户信息
         * UPDATE user SET name=?, email=? WHERE id=?
         */
        User user = new User();
        user.setId(4L);
        user.setName("李四");
        user.setEmail("lisi@qq.com");
        int rs = userMapper.updateById(user);
        System.out.println(rs);
    }

    @Test
    public void testSelect(){
        /**
         * 通过id查询用户信息
         * SELECT id,name,age,email FROM user WHERE id=?
         */
//        User user = userMapper.selectById(4L);
//        System.out.println(user);

        /**
         * 根据id批量查询用户信息
         * SELECT id,name,age,email FROM user WHERE id IN ( ? , ? )
         */
//        List<Long> list = Arrays.asList(4L,5L);
//        List<User> users = userMapper.selectBatchIds(list);
//        users.forEach(System.out::println);

        /**
         * 根据条件查询用户信息
         * SELECT id,name,age,email FROM user WHERE name = ? AND age = ?
         */
//       Map<String,Object> map = new HashMap<>();
//       map.put("name","李四");
//       map.put("age",21);
//       List<User> users = userMapper.selectByMap(map);
//       users.forEach(System.out::println);

        //自定义sql语句查询用户信息
        Map<String,Object> map = userMapper.selectMapById(1L);
        System.out.println(map);
    }



}