崛起于Springboot2.X + Mybatis:xml方式（3）

《SpringBoot2.X心法总纲》

mybatis编写方式：通过mapper.xml方式编写sql操作mysql数据库。

1、创建Springboot2.0 项目

1.1 new Project

1.2 创建springboot

1.3 Maven构建项目

1.4 选择2.0 以上的版本，勾选Web

1.5 在SQL上勾选Mysql 和Mybatis

1.6 Next，选择项目位置目录

1.7 创建项目目录结构图

2、配置集成mysql

2.1 application.properties配置属性

#mysql: 
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/ds 
spring.datasource.username=root spring.datasource.password=xiaonengweiwu
spring.datasource.driver-class-name=com.mysql.jdbc.Driver 
spring.datasource.max-idle=10 spring.datasource.max-wait=10000 
spring.datasource.min-idle=5 spring.datasource.initial-size=5

application.properties如下所示：

如果你想使用application.yml文件的话，更改下他的后缀名，改为yml就好，属性配置如图,类似于一个树形图，记住冒号后面需要有空格（‘：’ 需要有空格，才能显示颜色），而且要有层级关系。

3、集成Mybatis的xml方式

3.1 项目目录构建

mappings.xml文件内容为

<?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> 
    <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>

3.2 创建表结构

CREATE TABLE `user` (
  `id` varchar(50) DEFAULT NULL,
  `username` varchar(30) NOT NULL,
  `password` varchar(40) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1

3.3 实体类

public class User implements Serializable { 
    private String id; 
    private String username; 
    private String password;

    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
}

3.4 创建UserMapper

@Mapper 
public interface UserMapper { 
    User getUser(String id); 
    void delUser(String id); 
    void addUser(User user); 
    void updateUser(User user); 
}

3.5 创建UserService

@Service("userService") 
public class UserService { 
    @Resource UserMapper userMapper;
    public User getUser(String id){
        return userMapper.getUser(id);
    }
    @Transactional(isolation = Isolation.DEFAULT,propagation = Propagation.MANDATORY,readOnly = true)
    public void addUser(User user){
        userMapper.addUser(user);
    }
    public void delUser(String id){
        userMapper.delUser(id);
    }
    public void updateUser(User user){
       updateUser(user);
    }
}

这样，我们创建UserService成功，但是一般情况下，我们引入的userMapper出现红色下划线，是因为配置的原因，这里也能够正常运行，IDEA在编辑时提示could not autowire，解决办法 File-Project Structure 页面 Facets下删掉 Spring(直接右键Delete）

3.6 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.springboot2.mjt01.mapper.UserMapper">

<resultMap id="gainUsers" type="com.springboot2.mjt01.entity.User">
    <id property="id" column="id" jdbcType="VARCHAR" />
    <result property="username" column="username" jdbcType="VARCHAR" />
    <result property="password" column="password" jdbcType="VARCHAR" />
</resultMap>

<select id="getUser" parameterType="string" resultType="com.springboot2.mjt01.entity.User">
    select * from user
    where
    <if test="id != null">
        id = #{id}
    </if>
</select>

<insert id="addUser" parameterType="com.springboot2.mjt01.entity.User">
    INSERT INTO
    USER (id,username,password)
    VALUES
    (#{id},#{username,jdbcType=VARCHAR},#{password,jdbcType=VARCHAR})
</insert>
<insert id="addUsers" parameterType="java.util.List">
    INSERT INTO
    USER
    (id,username,password)
    VALUES
    <foreach collection="list" item="user" index="index" separator="" open="" close="">
      (#{id},#{username},#{password})
    </foreach>
</insert>

<delete id="delUser" parameterType="string">
    DELETE
    FROM USER
    WHERE
    id = #{id}
</delete>

<update id="updateUser" parameterType="com.springboot2.mjt01.entity.User">
    UPDATE
    USER
    SET
    id = #{id},
    username = #{username,jdbcType=VARCHAR},
    password = #{password,jdbcType=VARCHAR}
</update>
</mapper>

3.7 创建UserController

@Controller 
public class UserController {

    @Autowired 
    UserService userService

    @GetMapping(value = "/mjt/user/getUser",produces = "application/json")
    @ResponseBody
    public String getUser(){
        String id  = "3fa444d0-c149-48b1-bc3e-cbe1bdcda300";
        User user = userService.getUser(id);
        System.out.println(user.getPassword());
        System.out.println(user.getUsername());
        return user.getPassword()+user.getUsername();
    }

}

3.8 application.properties配置属性

#mybatis: 
mybatis.mapper-Locations=classpath:mapper/entity/*.xml mybatis.type-aliases-package=com.com.springboot2.mjt01.entity mybatis.config=classpath:mapper/mappings.xml

运行成功截图：

三种方法测试：

1、浏览器，不过只能支持Get方法

2、PostMan工具

3、Curl工具，你可以在gitBash上面也可以直接使用

来源：oschina

链接：https://my.oschina.net/u/3209213/blog/1834269

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Autowire

gitbash

YML

Spring Boot

MyBatis