SpringBoot整合Mybatis案例

2019/7/15以实习生身份入职公司前端做Angular ，但是感觉前途迷茫，于是乎学习一下Java的框架——SpringBooot。

参照大神博客：https://blog.csdn.net/iku5200/article/details/82856621#commentBox

新建一个SpringBoot项目

创建一个新项目。

创建项目的文件结构以及jdk的版本 

选择所需要的依赖

修改项目名，完成项目创建

建好后的pom.mxl文件

 <?xml version="1.0" encoding="UTF-8"?>

 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

     <modelVersion>4.0.0</modelVersion>

     <parent>

         <groupId>org.springframework.boot</groupId>

         <artifactId>spring-boot-starter-parent</artifactId>

         <version>2.1.7.RELEASE</version>

         <relativePath/> <!-- lookup parent from repository -->

     </parent>

     <groupId>com.example</groupId>

     <artifactId>demo</artifactId>

     <version>0.0.1-SNAPSHOT</version>

     <name>demo</name>

     <description>Demo project for Spring Boot</description>

     <properties>

         <java.version>1.8</java.version>

     </properties>

     <dependencies>

         <dependency>

             <groupId>org.springframework.boot</groupId>

             <artifactId>spring-boot-starter-jdbc</artifactId>

         </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>2.1.0</version>

         </dependency>

         <dependency>

             <groupId>mysql</groupId>

             <artifactId>mysql-connector-java</artifactId>

             <scope>runtime</scope>

         </dependency>

         <dependency>

             <groupId>org.springframework.boot</groupId>

             <artifactId>spring-boot-starter-test</artifactId>

             <scope>test</scope>

         </dependency>

     </dependencies>

     <build>

         <plugins>

             <plugin>

                 <groupId>org.springframework.boot</groupId>

                 <artifactId>spring-boot-maven-plugin</artifactId>

             </plugin>

         </plugins>

     </build>

 </project>

 修改配置文件

本文不使用application.properties文件 而使用更加简洁的application.yml文件。将resource文件夹下原有的application.properties文件删除，创建application.yml配置文件（备注：其实SpringBoot底层会把application.yml文件解析为application.properties），本文创建了两个yml文件（application.yml和application-dev.yml），分别来看一下内容。

application.yml

spring:

  profiles:

    active: dev

application-dev.yml

server:

  port: 8080

spring:

  datasource:

    username: root

    password: 123456

    url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC

    driver-class-name: com.mysql.jdbc.Driver

mybatis:

  mapper-locations: classpath:mapper/*Mapping.xml

  type-aliases-package: com.example.entity

logging:

  level:

    com:

      example:

        mapper:debug

两个文件的意思是：

创建包

创建包controller、entity、mapper、service。resources下创建mapping文件夹，用于写sql语句，也可以用注解的方式直接写在mapper文件里。

　　

数据库表结构

CREATE TABLE `user` (

  `id` int(32) NOT NULL AUTO_INCREMENT,

  `userName` varchar(32) NOT NULL,

  `passWord` varchar(50) NOT NULL,

  `realName` varchar(32) DEFAULT NULL,

  PRIMARY KEY (`id`)

) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;

　　

编写代码

编写实体类 User.java

package entity;

/**

 * @Auther wjw

 * @Date 2019-08-20

 */

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;

    }

    public String getPassWord() {

        return passWord;

    }

    public void setPassWord(String passWord) {

        this.passWord = passWord;

    }

    public String getRealName() {

        return realName;

    }

    public void setRealName(String realName) {

        this.realName = realName;

    }

    @Override

    public String toString() {

        return "User{" +

                "id=" + id +

                ", userName='" + userName + '\'' +

                ", passWord='" + passWord + '\'' +

                ", realName='" + realName + '\'' +

                '}';

    }

}

 编写控制类 UserController.java

package com.example.demo.controller;

import com.example.demo.service.UserService;

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;

/**

 * @ Author wjw

 * @ Date 2019-08-20

 */

@RestController

@RequestMapping("/testBoot")

public class UserController {

    @Autowired

    private UserService userService;

    @RequestMapping("getUser/{id}")

    public String GetUser(@PathVariable int id) {

        return userService.Sel(id).toString();

    }

}

 编写服务类 UserService.java

package com.example.demo.service;

import com.example.demo.mapper.UserMapper;

import com.example.demo.entity.User;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

/**

 * @ Author  wjw

 * @ Date  2019-08-20

 */

@Service

public class UserService {

    @Autowired

    UserMapper userMapper;

    public User Sel(int id) {

        return userMapper.Sel(id);

    }

}

编写 UserMapper.java.java

package com.example.demo.mapper;

import com.example.demo.entity.User;

import org.springframework.stereotype.Repository;

import org.apache.ibatis.annotations.Select;

/**

 * @ Author  wjw

 * @ Date  2019-08-20

 */

@Repository

public interface UserMapper {

    User Sel(int id);

}

 编写 UserMapping.xml 文件

<?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">

        <result 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>

    <select id="Sel" resultType="com.example.demo.entity.User">

        select * from user where id = #{id}

    </select>

</mapper>

最终框架结构

完成以上，下面在启动类里加上注解用于给出需要扫描的mapper文件路径@MapperScan("com.example.demo.mapper") 

package com.example.demo;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.mybatis.spring.annotation.MapperScan;

@MapperScan("com.example.demo.mapper")

@SpringBootApplication

public class DemoApplication {

    public static void main(String[] args) {

        SpringApplication.run(DemoApplication.class, args);

    }

}

运行

运行，最后启动，浏览器输入地址看看吧：http://localhost:8080/testBoot/getUser/1