Spring Boot与数据访问五--整合MyBatis(配置版)

      Spring Boot与数据访问一–Spring Data介绍
      Spring Boot与数据访问二–使用原生JDBC及源码解析
      Spring Boot与数据访问三–整合Druid
      Spring Boot与数据访问四–整合MyBatis(注解版)
      Spring Boot与数据访问五–整合MyBatis(配置版)
      Spring Boot与数据访问六–整合JPA
 

一、创建相应文件

创建mapper文件：

package com.huiq.springboot.mapper;

import com.huiq.springboot.entity.User;

import java.util.List;

// @Mapper或者@MapperScan将接口扫描装配到容器中
public interface UserMapper {

    public User getUserId(Integer id);

    public int insertUser(User user);

    List<User> findAll();
}

可以参考MyBatis的官网
SQL映射文件：

<?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.huiq.springboot.mapper.UserMapper">
    <!-- 自定义返回结果集 -->
    <resultMap id="userMap" type="User">
        <id property="id" column="id" javaType="java.lang.Integer"></id>
        <result property="name" column="name" javaType="java.lang.String"></result>
        <result property="password" column="password" javaType="java.lang.String"></result>
    </resultMap>

    <select id="getUserId" resultType="com.huiq.springboot.entity.User">
        SELECT * FROM tbl_user WHERE id=#{id}
    </select>
    
    <insert id="insertUser">
        INSERT INTO tbl_user(na_me,password) VALUES (#{name},#{password})
    </insert>

    <select id="findAll" resultType="User">
        SELECT * FROM tbl_user;
    </select>
</mapper>

注意：
1.namespace中需要与使用@Mapper的接口对应
2.UserMapper.xml文件名称必须与使用@Mapper的接口一致
3.标签中的id必须与@Mapper的接口中的方法名一致，且参数一致

全局配置文件：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!--  设置驼峰命名  -->
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>
</configuration>

注意：
1.全局配置文件不是必须有，没有该文件也可以启动成功，且开启驼峰命名也可以在application.yml中实现
2.mybatis中的mapper-locations是mapper的xml文件位置
3.mybatis中的type-aliases-package是为了配置xml文件中resultType返回值的包位置，如果未配置请使用全包名如下：

    <select id="findAll" resultType="com.huiq.springboot.entity.User">
        SELECT * FROM tbl_user;
    </select>

在application.yml文件中添加

mybatis:
  config-location: classpath:mybatis/mybatis-config.xml # 指定全局配置文件的位置
  # mapper-locations: classpth:mybatis/mapper/*.xml 或者下面的写法
  mapper-locations: classpath:mybatis/mapper/UserMapper.xml # 指定sql映射文件的位置
  type-aliases-package: com.huiq.springboot.entity
  #开启驼峰命名
#  configuration:
#    map-underscore-to-camel-case: true

controller：

package com.huiq.springboot.controller;

import com.huiq.springboot.entity.User;
import com.huiq.springboot.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class UserController {

    @Autowired
    UserMapper userMapper;

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

    @GetMapping("/user")
    public User insertUser(User user) {
        userMapper.insertUser(user);
        return user;
    }

    @RequestMapping("/findAll")
    public List<User> findAll(){
        return userMapper.findAll();
    }
}

启动程序测试


整个项目结构截图

二、优化为impl和service的形式

package com.huiq.springboot.service;

import com.huiq.springboot.entity.User;

import java.util.List;

public interface UserService {

    User getUserId(Integer id);

    int insertUser(User user);

    List<User> findAll();
}

注意：需要在接口实现类中使用@Service注解，才能被SpringBoot扫描，在Controller中使用@Authwired注入

package com.huiq.springboot.service.impl;

import com.huiq.springboot.entity.User;
import com.huiq.springboot.mapper.UserMapper;
import com.huiq.springboot.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service("userService")
public class UserServiceimpl implements UserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public User getUserId(Integer id) {
        return userMapper.getUserId(id);
    }

    @Override
    public int insertUser(User user) {
        return userMapper.insertUser(user);
    }

    @Override
    public List<User> findAll() {
        return userMapper.findAll();
    }
}

修改UserController为

package com.huiq.springboot.controller;

import com.huiq.springboot.entity.User;
import com.huiq.springboot.mapper.UserMapper;
import com.huiq.springboot.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class UserController {

    @Autowired
    UserService userService;

    @GetMapping("/user/{id}")
    public User getUser(@PathVariable("id") Integer id) {
        return userService.getUserId(id);
    }

    @GetMapping("/user")
    public User insertUser(User user) {
        userService.insertUser(user);
        return user;
    }

    @RequestMapping("/findAll")
    public List<User> findAll(){
        return userService.findAll();
    }
}

注：可以和我的另一篇不用Springboot搭建MyBatis文章作对比