9、SpringBoot整合mybatis

MyBatis-Spring-Boot-Starter官方文档：http://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/

maven仓库：https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter

依赖导入

1、导入 MyBatis 所需要的依赖

<!-- mybatis整合springboot -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.2</version>
</dependency>

2.、其他用到的依赖

pom.xml

<!-- web（web项目必须要的依赖，不然启动的就不是web项目） -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- mysql（数据库连接依赖） -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>
<!-- jdbc（mybatis-spring-boot-starter下存在这个包，可以不用导入） -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<!-- lombok（简化实体类） -->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
</dependency>
<!-- test(springboot自带依赖) -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>

3、配置数据库连接信息

application.yaml

spring:
  # 配置数据源
  datasource:
    username: root # 用户名
    password: 123456 # 密码
    # ?serverTimezone=UTC解决时区的报错
    url: jdbc:mysql://localhost:3306/mybatistest?useSSL=true&useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8
    driver-class-name: com.mysql.cj.jdbc.Driver # mysql驱动，新版用cj

# 整合mybatis
mybatis:
  type-aliases-package: com.yzh.pojo
  mapper-locations: classpath:mybatis/mapper/*Mapper.xml

4、测试数据库是否连接成功！（在测试类中注入DataSource，获取class信息和connection信息）

@SpringBootTest
class Springboot06MybatisApplicationTests {

    @Autowired
    DataSource dataSource;

    @Test
    void contextLoads() throws SQLException {
        System.out.println(dataSource.getClass());
        System.out.println(dataSource.getConnection());
    }

}

5、创建实体类，导入 Lombok！（使用Lombok必须导入依赖和配置插件）

User.java

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private Integer id; // ID
    private String name; // 用户名
    private String pwd; // 密码
}

6、创建mapper目录以及对应的 Mapper 接口

//@Mapper // 该注解表示这是 mybatis 的 mapper 类，也可以去主方法配置@MapperScan包扫描

//@Component // @Component 和 @Repository任选一个，都是注册作用，@Component更万能
@Repository //（可以不导入，但是使用@Autowired注入的时候可能不能被识别）
public interface UserMapper {

    List<User> queryUserList();

    User queryUserById(Integer id);

    int addUser(User user);

    int updateUser(User user);

    int deleteUser(Integer id);
    
}

7、对应的Mapper映射文件（放在了resource下的mybatis/mapper目录下）

UserMapper.xml

<?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.yzh.mapper.UserMapper">
    <select id="queryUserList" resultType="User">
        select * from mybatistest.user;
    </select>

    <select id="queryUserById" resultType="User">
        select * from mybatistest.user where id = #{id};
    </select>

    <insert id="addUser" parameterType="User">
        insert into mybatistest.user(id, name, pwd)
        values (#{id}, #{name}, #{pwd});
    </insert>

    <update id="updateUser" parameterType="User">
        update mybatistest.user
        set name = #{name},
            pwd = #{pwd}
        where id = #{id};
    </update>

    <delete id="deleteUser" parameterType="int">
        delete from mybatistest.user where id = #{id};
    </delete>

</mapper>

8、maven配置资源过滤问题（在pom文件的build标签下）

pom.xml

<!-- 资源过滤 -->
<resources>
    <resource>
        <directory>src/main/java</directory>
        <includes>
            <include>**/*.xml</include>
        </includes>
        <filtering>true</filtering>
    </resource>
</resources>

9、编写Controller 进行测试！

UserController.java

@RestController
public class UserController {

    @Autowired
    private UserMapper userMapper;

    @GetMapping("/userlist")
    public List<User> queryUserList(){
        return userMapper.queryUserList();
    }

    @GetMapping("/user/{id}")
    public User queryUserById(@PathVariable("id") Integer id){
        return userMapper.queryUserById(id);
    }

    @GetMapping("/adduser")
    public String addUser(){
        User user = new User(6,"admin4","111");
        userMapper.addUser(user);
        return "addok";
    }

    @GetMapping("/updateuser/{id}")
    public String updateUser(){
        User user = new User(6,"admin","000");
        userMapper.updateUser(user);
        return "updateok";
    }

    @GetMapping("delete/{id}")
    public String deleteUser(@PathVariable("id") Integer id){
        userMapper.deleteUser(id);
        return "deleteok";
    }

}

10、启动项目访问进行测试！

localhost:8080/下的各个方法依次测试。

至此，springboot整合mybatis 并且进行增删改查操作就全部结束了。

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