MybatisPlus快速入门案例

谁践踏了优雅 2022-11-18 01:42 186阅读 0赞

MybatisPlus的入门案很简单的，但是MybatisPlus却是不简单，任何技术学精通都需要一定的时间去学习，去实践，再进行总结，现在是科技快速发展的时代，以前程序员需要手写的代码，现在通过插件都可以自动生成了，而我们也需要跟上时代的步伐。

### 1、首先需要创建好数据库和准备好表格： ###

DROP TABLE IF EXISTS user;
    
    CREATE TABLE user
    (
    	id BIGINT(20) NOT NULL COMMENT '主键ID',
    	name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',
    	age INT(11) NULL DEFAULT NULL COMMENT '年龄',
    	email VARCHAR(50) NULL DEFAULT NULL COMMENT '邮箱',
    	PRIMARY KEY (id)
    );
    
    DELETE FROM user;
    
    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');

### 2、再创建springboot项目 ###

在这里就不展示步骤了，太简单了

### 3、引入的pom.xml依赖 ###

<dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
                <scope>runtime</scope>
                <optional>true</optional>
            </dependency>
    
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
    
            
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <optional>true</optional>
            </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>3.3.2</version>
            </dependency>

### 4、编辑好实体类和mapper包的文件 ###

/** * @author thunder */
    @Data
    public class User { 
        private Long id;
        private String name;
        private Integer age;
        private String email;
    }

### 5、使用接口继承BaseMapper,这样CRUD的方法就有了![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ0NzM5NzA2_size_16_color_FFFFFF_t_70] ###

/** * @author thunder */
    @Repository
    public interface UserMapper extends BaseMapper<User> { 
    }

### 6、接着再编辑properties文件： ###

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/MybatisPlus?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
    spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.username=root
    spring.datasource.password=123456

### 7、在入口类加上@MapperScan ###

这里是容易漏掉的地方，不加上就会报错

/** * @author thunder */
    @SpringBootApplication
    @MapperScan("com.thunder.mpdemo.mapper")
    public class MpdemoApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(MpdemoApplication.class, args);
        }
    
    }

### 8、接着就可以运行测试了： ###

@SpringBootTest
    class MpdemoApplicationTests { 
    
        @Autowired
        private UserMapper userMapper;
        
    	//查询操作
        @Test
         void testSelect() { 
            System.out.println(("----- selectAll method test ------"));
            List<User> userList = userMapper.selectList(null);
            userList.forEach(System.out::println);
        }
    
    
    
    //添加操作
     @Test
      void insert(){ 
        User user = new User();
        user.setName("李白");
        user.setAge(28);
        user.setEmail("lucyee@qq.com");
    
        int insert = userMapper.insert(user);
        System.out.println(insert);
      }
    //修改
      @Test
      void update(){ 
        User user = new User();
        user.setAge(38);
        user.setId(3L);
    
        int i = userMapper.updateById(user);
        System.out.println(i);
      }
      }

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ0NzM5NzA2_size_16_color_FFFFFF_t_70]: /images/20221022/7a2072b354144066b70715f92b3dd561.png