spring boot 和 mybatis集成

Posted 2020-10-20 NeverSayDie

1、pom.xml 添加mybatis和mysql依赖

　　　　<!-- 添加 MyBatis -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.2.0</version>
        </dependency>

        <!-- 添加 MySQL -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.41</version>
        </dependency>

2、application.properties 里面配置数据库信息

#数据库数据源配置
spring.datasource.url=jdbc:mysql://localhost/demo?useUnicode=true&characterEncoding=utf-8&allowMultiQueries=true
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

3、配置mybatis，有两种方式，一种用注解，一种用xml，一般习惯用XML。

• 用注解

@Mapper
public interface UserMapper {
    /**
     * 查询所有用户
     * @return
     */
    @Select("select id,name,age FROM tb_tic_user")
    List<UserDo> selectAll();
}

public class UserDo implements Serializable{

    private static final long serialVersionUID = -7488908967791971359L;
    private int Id;
    private String name;
    private int age;

    public int getId() {
        return Id;
    }

    public void setId(int id) {
        Id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "UserDo{" +
                "Id=" + Id +
                ", name=‘" + name + ‘\‘‘ +
                ", age=" + age +
                ‘}‘;
    }
}

@Controller
public class IndexController {

    @Autowired
    UserMapper userMapper;

    @RequestMapping("/selectAll")
    public @ResponseBody List<UserDo> selectAll(){
        return userMapper.selectAll();
    }

}

启动不报错，用注解配置成功，主要是在Mapper类上增加@Mapper注解，sql语句用注解放在方法上面。配置简单，但是会有重复代码，不推荐。

• 用xml配置，增加配置类用来扫描mapper接口

　　application.properties 中增加mybatis配置

#mybatis配置
mybatis.mapper-locations=classpath:mapper/*.xml
mybatis.type-aliases-package=com.example.demo.domain

@Configuration
@MapperScan(value = "com.example.demo.mapper")
public class MybatisConfig {
}

package com.example.demo.mapper;

import com.example.demo.domain.Test;

public interface TestMapper {
    int deleteByPrimaryKey(Integer id);

    int insert(Test record);

    int insertSelective(Test record);

    Test selectByPrimaryKey(Integer id);

    int updateByPrimaryKeySelective(Test record);

    int updateByPrimaryKey(Test record);
}

<?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.example.demo.mapper.TestMapper" >
  <resultMap id="BaseResultMap" type="com.example.demo.domain.Test" >
    <id column="ID" property="id" jdbcType="INTEGER" />
    <result column="NAME" property="name" jdbcType="VARCHAR" />
  </resultMap>
  <sql id="Base_Column_List" >
    ID, NAME
  </sql>
  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select 
    <include refid="Base_Column_List" />
    from tb_tic_test
    where ID = #{id,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    delete from tb_tic_test
    where ID = #{id,jdbcType=INTEGER}
  </delete>
  <insert id="insert" parameterType="com.example.demo.domain.Test" >
    insert into tb_tic_test (ID, NAME)
    values (#{id,jdbcType=INTEGER}, #{name,jdbcType=VARCHAR})
  </insert>
  <insert id="insertSelective" parameterType="com.example.demo.domain.Test" >
    insert into tb_tic_test
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        ID,
      </if>
      <if test="name != null" >
        NAME,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        #{id,jdbcType=INTEGER},
      </if>
      <if test="name != null" >
        #{name,jdbcType=VARCHAR},
      </if>
    </trim>
  </insert>
  <update id="updateByPrimaryKeySelective" parameterType="com.example.demo.domain.Test" >
    update tb_tic_test
    <set >
      <if test="name != null" >
        NAME = #{name,jdbcType=VARCHAR},
      </if>
    </set>
    where ID = #{id,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.example.demo.domain.Test" >
    update tb_tic_test
    set NAME = #{name,jdbcType=VARCHAR}
    where ID = #{id,jdbcType=INTEGER}
  </update>
</mapper>

@Controller
public class IndexController {
   
    @Autowired
    TestMapper testMapper;
   
    @RequestMapping("/test")
    public @ResponseBody Test test(){
        return testMapper.selectByPrimaryKey(1);
    }
}

习惯用xml，这样方便把基础方法提出来