spring boot 2整合mybatis

mybatis-spring-boot-starter主要有两种解决方案，一种是使用注解，一种是使用XML。

参考这篇文章动手跑了一个例子，稍微不同之处，原文是spring boot，这里改成了spring boot 2，mybatis现在最新版本为1.3.2。

一、使用注解

1、添加相关maven文件

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
         </dependency>

        <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>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

mybatis-spring-boot-starter最新版本可在官网查询
http://www.mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/index.html

2、application.properties 添加相关配置

mybatis.type-aliases-package = com.example.demo.entity

spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.url = jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8
spring.datasource.username = root
spring.datasource.password = 

3、实体类User.java

package com.example.demo.entity;

import com.example.demo.enums.UserSexEnum;

public class User {
    public User() {
        super();
    }
    
    public User(String name, UserSexEnum sex) {
        super();
        this.name = name;
        this.sex = sex;
    }
    
    private Integer id;

    private String name;

    private UserSexEnum sex;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name == null ? null : name.trim();
    }

    public UserSexEnum  getSex() {
        return sex;
    }

    public void setSex(UserSexEnum  sex) {
        this.sex = sex;
    } 
    
    @Override
    public String toString() {
        return "name " + this.name + ", sex " + this.sex;
    }
}

4、枚举UserSexEnum.java

package com.example.demo.enums;

public enum UserSexEnum {
    MAN, 
    WOMAN
}

5、启动类中添加对mapper包扫描@MapperScan，这样就不需要在每个Mapper类上面添加注解@Mapper。

package com.example.demo;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

@SpringBootApplication
@MapperScan("com.example.demo.mapper")
public class DemoApplication extends SpringBootServletInitializer {
    
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

6、开发Mapper

package com.example.demo.mapper;

import java.util.List;

import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import com.example.demo.entity.User;
import com.example.demo.enums.UserSexEnum;

public interface UserMapper {
    @Select("SELECT * FROM user")
       //结果集，关联实体类属性和数据库字段一一对应，如果两边一致，就不需要这个属性来修饰。
    @Results({        
        @Result(property = "sex",  column = "sex", javaType = UserSexEnum.class),
    })
    List<User> getAll();
    
    @Select("SELECT * FROM user WHERE id = #{id}")
    @Results({
        @Result(property = "sex",  column = "sex", javaType = UserSexEnum.class),
    })
    User getOne(Long id);

    @Insert("INSERT INTO user(name,sex) VALUES(#{name}, #{sex})")
    void insert(User user);

    @Update("UPDATE user SET name=#{name} WHERE id =#{id}")
    void update(User user);

    @Delete("DELETE FROM user WHERE id =#{id}")
    void delete(Long id);
}

7、单元测试

package com.example.demo.mapper;

import java.util.List;

import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import com.example.demo.entity.User;
import com.example.demo.enums.UserSexEnum;

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserMapperTest {

    @Autowired
    private UserMapper UserMapper;

    @Test
    public void testInsert() throws Exception {
        UserMapper.insert(new User("aa", UserSexEnum.MAN));
        UserMapper.insert(new User("bb", UserSexEnum.WOMAN));
        UserMapper.insert(new User("cc", UserSexEnum.WOMAN));

        Assert.assertEquals(3, UserMapper.getAll().size());
    }

    @Test
    public void testQuery() throws Exception {
        List<User> users = UserMapper.getAll();
        if(users==null || users.size()==0){
            System.out.println("is null");
        }else{
            System.out.println(users.toString());
        }
    }
    
    
    @Test
    public void testUpdate() throws Exception {
        User user = UserMapper.getOne(6l);
        System.out.println(user.toString());
        user.setName("dd");
        UserMapper.update(user);
        Assert.assertTrue(("dd".equals(UserMapper.getOne(6l).getName())));
    }

}

8、控制层

package com.example.demo.web;

import java.util.List;

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.RestController;

import com.example.demo.entity.User;
import com.example.demo.mapper.UserMapper;

@RestController
public class UserController {
    @Autowired
    private UserMapper userMapper;
    
    @RequestMapping("/getUsers")
    public List<User> getUsers() {
        List<User> users=userMapper.getAll();
        return users;
    }
    
    @RequestMapping("/getUser")
    public User getUser(Long id) {
        User user=userMapper.getOne(id);
        return user;
    }
    
    @RequestMapping("/add")
    public void save(User user) {
        userMapper.insert(user);
    }
    
    @RequestMapping(value="update")
    public void update(User user) {
        userMapper.update(user);
    }
    
    @RequestMapping(value="/delete/{id}")
    public void delete(@PathVariable("id") Long id) {
        userMapper.delete(id);
    }
}

项目目录结构：

二、使用XML

1、application.properties新增以下配置

mybatis.config-location = classpath:mybatis/mybatis-config.xml
mybatis.mapper-locations = classpath:mybatis/mapper/*.xml

2、在resources/mybatis目录下添加mybatis-config.xml配置

<?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>
    <settings>
        <!-- 控制台打印查询语句 -->
        <setting name="logImpl" value="STDOUT_LOGGING" />
    </settings>
    <typeAliases>
        <typeAlias alias="Integer" type="java.lang.Integer" />
        <typeAlias alias="Long" type="java.lang.Long" />
        <typeAlias alias="HashMap" type="java.util.HashMap" />
        <typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap" />
        <typeAlias alias="ArrayList" type="java.util.ArrayList" />
        <typeAlias alias="LinkedList" type="java.util.LinkedList" />
    </typeAliases>
</configuration>

3、添加映射文件UserMapper.xml

<?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.UserMapper" >
    <resultMap id="BaseResultMap" type="com.example.demo.entity.User" >
        <id column="id" property="id" jdbcType="BIGINT" />
        <result column="name" property="name" jdbcType="VARCHAR" />
        <result column="sex" property="sex" javaType="com.example.demo.enums.UserSexEnum"/>
    </resultMap>
    
    <sql id="Base_Column_List" >
        id, name, sex
    </sql>

    <select id="getAll" resultMap="BaseResultMap"  >
       SELECT 
       <include refid="Base_Column_List" />
       FROM user
    </select>

    <select id="getOne" parameterType="java.lang.Long" resultMap="BaseResultMap" >
        SELECT 
       <include refid="Base_Column_List" />
       FROM user
       WHERE id = #{id}
    </select>

    <insert id="insert" parameterType="com.example.demo.entity.User" >
       INSERT INTO 
               user
               (name,sex) 
           VALUES
               (#{name},  #{sex})
    </insert>
    
    <update id="update" parameterType="com.example.demo.entity.User" >
       UPDATE 
               user 
       SET        
           name = #{name}
       WHERE 
               id = #{id}
    </update>
    
    <delete id="delete" parameterType="java.lang.Long" >
       DELETE FROM
                user 
       WHERE 
                id =#{id}
    </delete>

</mapper>

4、编写Dao层的代码

package com.example.demo.mapper;

import java.util.List;

import com.example.demo.entity.User;

public interface UserMapper {
    
    List<User> getAll();
    
    User getOne(Long id);

    void insert(User user);

    void update(User user);

    void delete(Long id);
}

项目目录结构：