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 ('1', 'anson', '123', '张三');
INSERT INTO `user` VALUES ('2', 'Alex', '123', '李四');
INSERT INTO `user` VALUES ('3', 'kks', '123', '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 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, userName, passWord, realName
  </sql>
  <select >
    select 
    <include ref>
    from user
    where id = #{id,jdbcType=INTEGER}
  </select>
  <delete >
    delete from user
    where id = #{id,jdbcType=INTEGER}
  </delete>
  <insert >
    insert into user (id, userName, passWord, 
      realName)
    values (#{id,jdbcType=INTEGER}, #{username,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR}, 
      #{realname,jdbcType=VARCHAR})
  </insert>
  <insert >
    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 >
    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 >
    update user
    set userName = #{username,jdbcType=VARCHAR},
      passWord = #{password,jdbcType=VARCHAR},
      realName = #{realname,jdbcType=VARCHAR}
    where id = #{id,jdbcType=INTEGER}
  </update>
</mapper>

View Code