Spring Boot教程(六)：Spring Boot集成mybatis

刺骨的言语ヽ痛彻心扉 2022-05-26 12:51 258阅读 0赞

# 一、前置条件 #

先创建好一个最简单的spring boot项目，可参考之前章节的源代码或直接自己创建一个。

# 二、创建数据库 #

创建数据库

create database springboot;

创建用户表`tbl_user`并插入测试数据

CREATE TABLE `tbl_user` ( `user_id` bigint(20) NOT NULL, `user_name` varchar(50) DEFAULT NULL, `user_age` int(11) DEFAULT NULL, PRIMARY KEY (`user_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
    
    INSERT INTO `tbl_user` VALUES (1, '张三', 27);
    INSERT INTO `tbl_user` VALUES (2, '李四', 30);
    INSERT INTO `tbl_user` VALUES (3, '王五', 20);

脚本sql在源码的db文件夹中。

# 三、引入mybatis依赖 #

<dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>1.3.2</version>
    </dependency>
    
    
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>

# 四、编写代码 #

1、创建实体

package com.songguoliang.mybatis.entity;
    
    /** * @Description * @Author sgl * @Date 2018-05-02 14:59 */
    public class User { 
        private Long userId;
        private String userName;
        private Integer userAge;
    
        public Long getUserId() {
            return userId;
        }
    
        public void setUserId(Long userId) {
            this.userId = userId;
        }
    
        public String getUserName() {
            return userName;
        }
    
        public void setUserName(String userName) {
            this.userName = userName;
        }
    
        public Integer getUserAge() {
            return userAge;
        }
    
        public void setUserAge(Integer userAge) {
            this.userAge = userAge;
        }
    }

2、创建Mapper文件

在`resources`文件夹下创建`mapper`文件夹，然后在`mapper`文件夹里创建`UserMapper.xml`，内容如下：

<?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.songguoliang.mybatis.mapper.UserMapper">
    
        <select id="getUsers" resultType="User">
            SELECT * FROM tbl_user
        </select>
    
    </mapper>

3、创建Mapper(Dao)接口

package com.songguoliang.mybatis.mapper;
    
    import com.songguoliang.mybatis.entity.User;
    
    import java.util.List;
    
    /** * @Description * @Author sgl * @Date 2018-05-02 15:02 */
    public interface UserMapper { 
    
        List<User> getUsers();
    }

4、创建Service

package com.songguoliang.mybatis.service;
    
    import com.songguoliang.mybatis.entity.User;
    import com.songguoliang.mybatis.mapper.UserMapper;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    import java.util.List;
    
    /** * @Description * @Author sgl * @Date 2018-05-02 15:01 */
    @Service
    public class UserService { 
    
        @Autowired
        private UserMapper userMapper;
    
        public List<User> getUsers() {
            return userMapper.getUsers();
        }
    }

5、创建controller

package com.songguoliang.mybatis.controller;
    
    import com.songguoliang.mybatis.entity.User;
    import com.songguoliang.mybatis.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import java.util.List;
    
    /** * @Description * @Author sgl * @Date 2018-05-02 14:59 */
    @RestController
    public class UserController { 
    
        @Autowired
        private UserService userService;
    
        @GetMapping("/users")
        public List<User> lists() {
            return userService.getUsers();
        }
    
    }

# 五、配置mybatis #

1、配置数据源

在`application.properties`配置文件中添加如下代码：

## 数据源配置
    spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&useSSL=false
    spring.datasource.username=root
    spring.datasource.password=root
    spring.datasource.driver-class-name=com.mysql.jdbc.Driver

2、添加mybatis配置

在`application.properties`配置文件中添加mybatis的配置，如下代码：

# mybatis
    mybatis.type-aliases-package=com.songguoliang.mybatis.entity
    mybatis.mapper-locations=classpath:mapper/*.xml mybatis.configuration.map-underscore-to-camel-case=true

*  `mybatis.type-aliases-package`：别名类(实体类)所在包
 *  `mybatis.mapper-locations`：mapper文件所在文件夹
 *  `mybatis.configuration.map-underscore-to-camel-case`：采用驼峰命名方式转换

3、扫描Mapper接口

在启动类上添加注解`@MapperScan("com.songguoliang.mybatis.mapper")` ，注意`MapperScan`的包路径(`org.mybatis.spring.annotation.MapperScan`)，后面章节和Mapper4集成时会修改导入的包。

package com.songguoliang.mybatis;
    
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    /** * @Description * @Author sgl * @Date 2018-05-02 14:51 */
    @SpringBootApplication
    @MapperScan("com.songguoliang.mybatis.mapper")
    public class MybatisApplication { 
        public static void main(String[] args) {
            SpringApplication.run(MybatisApplication.class, args);
        }
    }

# 六、测试 #

启动服务，浏览器输入`http://localhost:8080/users` ,可看到如下内容：  
![这里写图片描述][70]

源码：  
[github][]  
[码云][Link 1]

[70]: /images/20220526/31566fc818e94484be390f6ff3ec0f67.png
[github]: https://github.com/itinypocket/spring-boot-study/tree/master/spring-boot-mybatis
[Link 1]: https://gitee.com/itinypocket/spring-boot-study/tree/master/spring-boot-mybatis