小白的springboot之路（三）、集成mybatis与MySQL

0、前言

　　mybatis属于半自动的ORM，相比hibernate这种全自动的ORM，兼顾了性能与易用；目前企业项目中，基本都是mybatis的天下；今天就来整合mybatis与MySQL；

1、整合

　　1.-1、添加依赖：

        <!-- 集成mybatis -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.0</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.16</version>
        </dependency>

1-2、创建数据表：

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `id` int(32) NOT NULL AUTO_INCREMENT COMMENT '用户ID',
  `userName` varchar(32) NOT NULL COMMENT '用户名称',
  `passWord` varchar(50) NOT NULL COMMENT '用户密码',
  `realName` varchar(32) DEFAULT NULL COMMENT '中文名字',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES ('', 'anson', '', '张三');
INSERT INTO `user` VALUES ('', 'Alex', '', '李四');
INSERT INTO `user` VALUES ('', 'kks', '', '王五');

1-3、增加实体类User.java

package com.anson.model;

public class User {
    private Integer id;
    private String username;
    private String password;
    private String realname;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username == null ? null : username.trim();
    }
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password == null ? null : password.trim();
    }
    public String getRealname() {
        return realname;
    }
    public void setRealname(String realname) {
        this.realname = realname == null ? null : realname.trim();
    }
}

1-4、增加Mapper接口UserMapper.java；注意添加@Repository注解

package com.anson.dao;

import com.anson.model.User;
import org.springframework.stereotype.Repository;

@Repository  //添加Repository注解
public interface UserMapper {
    int deleteByPrimaryKey(Integer id);

    int insert(User record);

    int insertSelective(User record);

    User selectByPrimaryKey(Integer id);

    int updateByPrimaryKeySelective(User record);

    int updateByPrimaryKey(User record);
}

1-5、添加Mapper对应的XML文件UserMapper.xml，注意<mapper namespace="com.anson.dao.UserMapper">对应Mapper包

<?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.anson.dao.UserMapper">
  <resultMap id="BaseResultMap" type="com.anson.model.User">
    <id column="id" jdbcType="INTEGER" property="id" />
    <result column="userName" jdbcType="VARCHAR" property="username" />
    <result column="passWord" jdbcType="VARCHAR" property="password" />
    <result column="realName" jdbcType="VARCHAR" property="realname" />
  </resultMap>
  <sql id="Base_Column_List">
    id, userName, passWord, realName
  </sql>
  <select id="selectByPrimaryKey" parameterType="java.lang.Integer" resultMap="BaseResultMap">
    select
    <include refid="Base_Column_List" />
    from user
    where id = #{id,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer">
    delete from user
    where id = #{id,jdbcType=INTEGER}
  </delete>
  <insert id="insert" parameterType="com.anson.model.User">
    insert into user (id, userName, passWord,
      realName)
    values (#{id,jdbcType=INTEGER}, #{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR},
      #{realname,jdbcType=VARCHAR})
  </insert>
  <insert id="insertSelective" parameterType="com.anson.model.User">
    insert into user
    <trim prefix="(" suffix=")" suffixOverrides=",">
      <if test="id != null">
        id,
      </if>
      <if test="username != null">
        userName,
      </if>
      <if test="password != null">
        passWord,
      </if>
      <if test="realname != null">
        realName,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides=",">
      <if test="id != null">
        #{id,jdbcType=INTEGER},
      </if>
      <if test="username != null">
        #{username,jdbcType=VARCHAR},
      </if>
      <if test="password != null">
        #{password,jdbcType=VARCHAR},
      </if>
      <if test="realname != null">
        #{realname,jdbcType=VARCHAR},
      </if>
    </trim>
  </insert>
  <update id="updateByPrimaryKeySelective" parameterType="com.anson.model.User">
    update user
    <set>
      <if test="username != null">
        userName = #{username,jdbcType=VARCHAR},
      </if>
      <if test="password != null">
        passWord = #{password,jdbcType=VARCHAR},
      </if>
      <if test="realname != null">
        realName = #{realname,jdbcType=VARCHAR},
      </if>
    </set>
    where id = #{id,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.anson.model.User">
    update user
    set userName = #{username,jdbcType=VARCHAR},
      passWord = #{password,jdbcType=VARCHAR},
      realName = #{realname,jdbcType=VARCHAR}
    where id = #{id,jdbcType=INTEGER}
  </update>
</mapper>

1-6、编写service接口UserService.java:

package com.anson.service;

import com.anson.model.User;

public interface UserService
{
    int deleteByPrimaryKey(Integer id);
    int insert(User record);
    int insertSelective(User record);
    User selectByPrimaryKey(Integer id);
    int updateByPrimaryKeySelective(User record);
    int updateByPrimaryKey(User record);
}

编写接口实现类UserServiceImpl.java，注意增加@Service注解：

package com.anson.service.Impl;

        import com.anson.dao.UserMapper;
        import com.anson.model.User;
        import com.anson.service.UserService;
        import org.springframework.beans.factory.annotation.Autowired;
        import org.springframework.stereotype.Service;

/**
 * @description: service实现类
 * @author: anson
 * @Date: 2019/9/5 0:37
 * @version: 1.0
 */
@Service
public class UserServiceImpl implements UserService
{
    @Autowired
    UserMapper usermapper;

    @Override
    public User selectByPrimaryKey(Integer id)
    {
        return  usermapper.selectByPrimaryKey(id);
    }
    @Override
    public int deleteByPrimaryKey(Integer id)
    {
        return   usermapper.deleteByPrimaryKey(id);
    }
    @Override
    public  int insert(User record)
    {
        return  usermapper.insert(record);
    }
    @Override
    public int insertSelective(User record)
    {
        return  usermapper.insertSelective(record);
    }
    @Override
    public int updateByPrimaryKeySelective(User record)
    {
        return  usermapper.updateByPrimaryKeySelective(record);
    }
    @Override
    public int updateByPrimaryKey(User record)
    {
        return  usermapper.updateByPrimaryKey(record);
    }

}

1-7、编写controller:

package com.anson.controller;

import com.anson.model.User;
import com.anson.service.UserService;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiImplicitParam;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

/**
 * @description: TODO
 * @author: anson
 * @Date: 2019/9/5 0:42
 * @version: 1.0
 */

@RestController
@Api(value = "用户接口")
@RequestMapping("/user")
public class UserController
{
    @Autowired
    private UserService userservice;

    @ApiOperation(value = "获取用户", notes = "根据id查询用户信息")
    @ApiImplicitParam(name = "id", value = "用户id", required=true, dataType="int") //API参数
    @RequestMapping(value="/getUserById/{id}",method= RequestMethod.GET)
    public User selectByPrimaryKey(@PathVariable int id)
    {
        return userservice.selectByPrimaryKey(id);
    }
}

1-8、启动类中增加包扫描注解：

@SpringBootApplication
@MapperScan("com.anson.dao") //增加Mapper包扫描注解
public class application
{
    public static   void main(String[] args)
    {
        SpringApplication.run(application.class,args);
    }
}

1-9、配置文件中增加数据源和mybatis的注解：

#服务器配置
server.port=8090

#mysql数据源配置
spring.datasource.driverClassName = com.mysql.cj.jdbc.Driver
spring.datasource.url = jdbc:mysql://localhost:3306/mydb?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
spring.datasource.username = root
spring.datasource.password =88888888

#mybatis配置
mybatis.type-aliases-package=com.anson.model
mybatis.mapperLocations=classpath:mapper/*Mapper.xml

#showSql
logging.level.com.anson.dao=debug

好了，完毕，运行，可以在swagger中查看和运行接口：

可以看到已经正常运行了；

好了，本节到此为止，下节将讲介绍mybatis-generator自动生成实体、mapper和mapper对应的XML

源码地址：https://github.com/anson-yang/cloverDemo.git