SpringBoot和MyBatis可以说是现在最主流的后端框架,是基础中的基础
创建工程
创建Springboot工程,记得勾选 web、web Servic、mybatis、mysql和lombok
pom.xml中应至少有以下依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web-services</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.1.2</version>
</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>
同时我最终的目录结构如下:
构建输入库
其对应的数据库 Schema 脚本如下:
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)
);
其对应的数据库 Data 脚本如下:
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');
创建实体类User
使用了lombok插件
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private Long id;
private String name;
private Integer age;
private String email;
}
创建接口UserRepository
添加5个增删该查的方法
public interface UserRepository {
int save(User user);
int update(User user);
int deleteById(long id);
List<User> findAll();
User findById(long id);
}
创建接口对应的mapper
创建UserRepository.xml,并编写对应接口的5个方法
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.mybatis.repository.UserRepository">
<insert id="save" parameterType="com.example.mybatis.entity.User">
INSERT INTO user (id, name, age, email) VALUES (#{id}, #{name}, #{age}, #{email})
</insert>
<update id="update" parameterType="com.example.mybatis.entity.User">
update user set name = #{name},age = #{age},email = #{email} where id = #{id}
</update>
<delete id="deleteById" parameterType="long">
delete from user where id = #{id}
</delete>
<select id="findAll" resultType="com.example.mybatis.entity.User">
select * from user
</select>
<select id="findById" parameterType="long" resultType="com.example.mybatis.entity.User">
select * from user where id = #{id}
</select>
</mapper>
创建配置文件application.yml
spring:
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai&useSSL=false
username: root
password: root
mybatis:
# 指定实体类包路径
typeAliasesPackage: com.example.mybatis.entity
# 指定xml文件扫描路径
mapper-locations: classpath*:mapper/*.xml
SpringBoot启动类
在创建项目自动生成的启动类上添加@MapperScan
,其中的值是你接口的路径,如下所示,
@SpringBootApplication
@MapperScan("com.example.mybatis.repository")
public class MybatisApplication {
public static void main(String[] args) {
SpringApplication.run(MybatisApplication.class, args);
}
}
编写UserController
注意Controller类的上方要有@RestController
注解
@RestController
public class UserController {
@Autowired
private UserRepository userRepository;
@GetMapping("/findAll")
public List<User> findAll() {
return userRepository.findAll();
}
@GetMapping("/findAll/{id}")
public User findById(@PathVariable("id") Long id) {
return userRepository.findById(id);
}
@PostMapping("/save")
public void save(@RequestBody User user) {
userRepository.save(user);
}
@PutMapping("/update")
public void update(@RequestBody User user) {
userRepository.update(user);
}
@DeleteMapping("/delete/{id}")
public void delete(@PathVariable Long id) {
userRepository.deleteById(id);
}
}
测试
运行启动类,在浏览器或者postman上试试吧
方法我都实际运行过,没有问题,如果你不会使用save和update方法,可以看下图,这是update方法,需要注意画圈圈的几点地方
结语
有错误请及时指出
Q.E.D.