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Mybatis-plus入门demo

Spring Boot 2.0.6
数据库：mysql
Maven：
添加依赖
引入 Spring Boot Starter 父工程：

org.springframework.boot spring-boot-starter-parent 2.1.4.RELEASE 引入 spring-boot-starter、spring-boot-starter-test、mybatis-plus-boot-starter、lombok、h2 依赖： org.springframework.boot spring-boot-starter org.springframework.boot spring-boot-starter-test test org.projectlombok lombok true com.baomidou mybatis-plus-boot-starter 3.1.0 mysql mysql-connector-java

application.yml
spring:
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/helloworld?serverTimezone=UTC
username: root
password: 123

数据库表结构
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’);

在 Spring Boot 启动类中添加 @MapperScan 注解，扫描 Mapper 文件夹：

@SpringBootApplication
@MapperScan(“com.baomidou.mybatisplus.samples.quickstart.mapper”)
public class Application {

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

}

编码

编写实体类 User.java（此处使用了 Lombok 简化代码）

@Data
public class User {
private Long id;
private String name;
private Integer age;
private String email;
}
编写Mapper类 UserMapper.java

public interface UserMapper extends BaseMapper {

}

开始使用

添加测试类，进行功能测试：

@RunWith(SpringRunner.class)
@SpringBootTest
public class SampleTest {

@Autowired
private UserMapper userMapper;

@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);
}

}
TIP

UserMapper 中的 selectList() 方法的参数为 MP 内置的条件封装器 Wrapper，所以不填写就是无任何条件

控制台输出：

User(id=1, name=Jone, age=18, email=test1@baomidou.com)
User(id=2, name=Jack, age=20, email=test2@baomidou.com)
User(id=3, name=Tom, age=28, email=test3@baomidou.com)
User(id=4, name=Sandy, age=21, email=test4@baomidou.com)
User(id=5, name=Billie, age=24, email=test5@baomidou.com)