SpringBoot+Mybatis+Mysql用法Demo

一时失言乱红尘 2023-02-27 12:28 129阅读 0赞

本文基于**SpringBoot+Mybatis+Mysql5.5**完成了一个简单Demo，实现了基本CRUD功能。开发工具为Eclipse。

# 一：利用Eclipse创建一个Maven功能，创建方法如下 #

[Eclipse创建Maven工程][Eclipse_Maven]

# 二：修改pom.xml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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
    
        <groupId>springboot</groupId>
        <artifactId>springboot</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>springboot</name>
    
        
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.3.RELEASE</version>
        </parent>
    
        <dependencies>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    		<dependency>
    	    	<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
            
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.0.0</version>
            </dependency>
            
            <dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-jdbc</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    			<scope>runtime</scope>
    		</dependency>
        </dependencies>
    </project>

# 三：创建application.yml和application-dev.yml配置文件 #

**application.yml**

spring:
      profiles:
        active: dev

**application-dev.yml**

server:
      port: 8086
     
    spring:
      datasource:
        username: root
        password: root
        url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
        driver-class-name: com.mysql.cj.jdbc.Driver
     
    mybatis:
      mapper-locations: classpath:mapping/*Mapper.xml
      type-aliases-package: org.spring.springboot.entity
     
    
    #showSql
    logging:
      level:
        com:
          example:
            mapper : debug

> 在项目中配置多套环境的配置方法。  
> 因为现在一个项目有好多环境，开发环境，测试环境，准生产环境，生产环境。每个环境的参数不同，所以我们就可以把每个环境的参数配置到yml文件中，这样在想用哪个环境的时候只需要在主配置文件中将用的配置文件写上就行，如application.yml  
> 在Spring Boot中多环境配置文件名需要满足application-\{profile\}.yml的格式，其中\{profile\}对应你的环境标识，比如：  
> application-dev.yml：开发环境  
> application-test.yml：测试环境  
> application-prod.yml：生产环境  
> 至于哪个具体的配置文件会被加载，需要在application.yml文件中通过spring.profiles.active属性来设置，其值对应\{profile\}值。

**注意**：这里由于采用mysql5.5数据库，所以驱动写成了`com.mysql.cj.jdbc.Driver`  
，否则会报如下错误：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70]  
解决方案为：[解决springboot连接MySQL数据库报错问题][springboot_MySQL]

# 四：创建包controller、entity、mapper、service，以及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） #

如果Eclipse中resources下创建mapping文件夹显示异常，比如显示为包图标，解决方案如下：  
[解决eclipse maven工程中src/main/resources目录下创建的文件夹所显示样式不是文件夹，而是"包"图标样式的问题][eclipse maven_src_main_resources]

## 1：数据库表User ##

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;

效果如下  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 1]

## 2：实体类User.java ##

package org.spring.springboot.entity;
    
    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 + '\'' +
                    '}';
        }
    }

## 3：控制层UserController.java ##

package org.spring.springboot.controller;
    
    import javax.servlet.http.HttpServletRequest;
    import org.spring.springboot.entity.User;
    import org.spring.springboot.service.UserService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.ResponseBody;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    @RequestMapping("/testBoot")
    public class UserController { 
    
    	@Autowired
    	private UserService userService;
    
    	// 查询
    	@RequestMapping("/getUser/{id}")
    	@ResponseBody
    	public String GetUser(@PathVariable int id) { 
    		return userService.Sel(id).toString();
    	}
    
    	// 更新
    	@RequestMapping("/updateUser")
    	@ResponseBody
    	public String updateUser(HttpServletRequest request) { 
    		String realName = request.getParameter("realName");
    		int id = Integer.parseInt(request.getParameter("id"));
    		User user = new User();
    		user.setRealName(realName);
    		user.setId(id);
    		if (userService.updateUserById(user)) { 
    			return "更新成功！";
    		} else { 
    			return "更新失败！";
    		}
    	}
    
    	// 新增
    	@RequestMapping("/insertUser")
    	@ResponseBody
    	public String insertUser(HttpServletRequest request) { 
    		int id = Integer.parseInt(request.getParameter("id"));
    		String userName = request.getParameter("userName");
    		String passWord = request.getParameter("passWord");
    		String realName = request.getParameter("realName");
    		User user = new User();
    		user.setId(id);
    		user.setUserName(userName);
    		user.setPassWord(passWord);
    		user.setRealName(realName);
    		if (userService.insertUser(user)) { 
    			return "插入成功！";
    		} else { 
    			return "插入失败！";
    		}
    	}
    
    	// 删除
    	@RequestMapping("/deleteById")
    	@ResponseBody
    	public String deleteById(int id) { 
    		if (userService.deleteById(id)) { 
    			return "删除成功！";
    		} else { 
    			return "删除失败！";
    		}
    	}
    
    }

## 4：实现类UserService.java ##

package org.spring.springboot.service;
    
    import org.spring.springboot.entity.User;
    import org.spring.springboot.mapper.UserMapper;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    @Service
    public class UserService { 
        @Autowired
        UserMapper userMapper;
        
        //查询
        public User Sel(int id){ 
            return userMapper.Sel(id);
        }
        
        //更新
        public boolean updateUserById(User user) { 
        	userMapper.updateUserById(user);
            return true;
        }
        
        //新增
        public boolean insertUser(User user) { 
        	userMapper.insertUser(user);
            return true;
        }
        
        //删除
        public boolean deleteById(int id) { 
        	userMapper.deleteById(id);
            return true;
        }
            
    }

## 5：业务映射UserMapper.java ##

package org.spring.springboot.mapper;
    
    import org.apache.ibatis.annotations.Mapper;
    import org.spring.springboot.entity.User;
    import org.springframework.stereotype.Repository;
    
    /* *如果启动类不添加mapper映射，则此处需要添加mapper注解 */
    @Mapper
    @Repository
    public interface UserMapper { 
        //查询
        User Sel(int id);
        //更新
        boolean updateUserById(User user);
        //新增
        boolean insertUser(User user);
        //删除
        boolean deleteById(int id);
    }

## 6：映射配置文件UserMapping.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="org.spring.springboot.mapper.UserMapper">
     
        <resultMap id="BaseResultMap" type="org.spring.springboot.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="org.spring.springboot.entity.User">
            select * from user where id = #{id}
        </select>
        
        
        
        <update id="updateUserById" parameterType="org.spring.springboot.entity.User">
            update user set realName = #{realName} where 
            <if test="id!= null and id!= ''">
                   id = #{id}
            </if>
        </update>
        
        
        <insert id="insertUser" parameterType="org.spring.springboot.entity.User">
            insert into user(id,userName,passWord,realName) values (#{id},#{userName},#{passWord},#{realName}) 
        </insert>
        
        <delete id="deleteById" parameterType="org.spring.springboot.entity.User">
        	delete from user where id = #{id}
        </delete>
        
     </mapper>

这里记录一个错误及其解决方案：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 2]  
[Caused by: org.xml.sax.SAXParseException; 必须为元素类型 “update” 声明属性 “resultType”][Caused by_ org.xml.sax.SAXParseException_ _ _update_ _ _resultType]

## 7：启动类 ##

package org.spring.springboot;
    
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    /** * Spring Boot 应用启动类 * */
    /* UserMapper.java 如果不添加Mapper注解，则此处需要添加MapperScan @MapperScan("com.example.mapper") */
    @SpringBootApplication
    public class ApplicationApp { 
    
        public static void main(String[] args) { 
            // 程序启动入口
            // 启动嵌入式的 Tomcat 并初始化 Spring 环境及其各 Spring 组件
            SpringApplication.run(ApplicationApp.class,args);
        }
    }

## 8：项目最终框架结构 ##

![在这里插入图片描述][20200717190250277.png]  
注意：项目中org.spring.springboot.web包里面内容与本项目无关，仅仅是aop的练习，可以忽略。  
最后启动工程  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 3]  
**完成项目下载地址如下**：  
[本文Demo工程代码][Demo]

（1）浏览器输入**查询**地址：`http://localhost:8080/testBoot/getUser/1`  
查询结果如下：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 4]  
（2）浏览器输入**更新**地址：`http://localhost:8086/testBoot/updateUser?id=2&realName=许三多`  
查询结果如下：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 5]

（3）浏览器输入**新增**地址：`http://localhost:8086/testBoot/insertUser?id=3&userName=test3&passWord=test3password&realName=许三多3`  
查询结果如下：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 6]

（4）浏览器输入**删除**地址：`http://localhost:8086/testBoot/deleteById?id=3`  
查询结果如下：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 7]

# 五、Mybatis批量插入数据解决方案 #

## 方案1：普通for循环插入 ##

UserController

// 新增
    	@RequestMapping("/insertUser")
    	@ResponseBody
    	public String insertUser(HttpServletRequest request) { 
    		/* int id = Integer.parseInt(request.getParameter("id")); String userName = request.getParameter("userName"); String passWord = request.getParameter("passWord"); String realName = request.getParameter("realName"); User user = new User(); user.setId(id); user.setUserName(userName); user.setPassWord(passWord); user.setRealName(realName); */
    		if (userService.insertUser()) { 
    			return "插入成功！";
    		} else { 
    			return "插入失败！";
    		}
    	}

UserService

//新增
        public boolean insertUser() { 
        	 //普通for循环插入
        	 for (int i = 0; i <20; i++) { 
        	    User user = new User();
        		user.setId(i);
        		user.setUserName("testusername" + i);
        		user.setPassWord("testpassword"+i);
        		user.setRealName("testrealname"+i);
        		userMapper.insertUser(user);
        	  }
        	//userMapper.insertUser(user);
            return true;
        }

UserMapper.xml

<insert id="insertUser" parameterType="org.spring.springboot.entity.User">
            insert into user(id,userName,passWord,realName) values (#{id},#{userName},#{passWord},#{realName}) 
        </insert>

执行`http://localhost:8086/testBoot/insertUser`插入结果如下：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 8]

## 方案2：foreach方式插入 ##

UserController同方案一，保持不变  
UserMapper

/* *如果启动类不添加mapper映射，则此处需要添加mapper注解 */
    @Mapper
    @Repository
    public interface UserMapper { 
    	List<User> list = new ArrayList<>();
        //查询
        User Sel(int id);
        //更新
        boolean updateUserById(User user);
        //新增
        //boolean insertUser(User user);
        //新增
        boolean insertUser(List<User> user);
        //删除
        boolean deleteById(int id);
    }

UserService更改如下

//新增
        public boolean insertUser() { 
        	 /* //普通for循环插入 for (int i = 0; i <20; i++) { User user = new User(); user.setId(i); user.setUserName("testusername" + i); user.setPassWord("testpassword" + i); user.setRealName("testrealname"+i); userMapper.insertUser(user); } */
        	//userMapper.insertUser(user);
        	List<User> list1 = new ArrayList<>();
        	for (int i = 0; i <20; i++) { 
        	    User user = new User();
        		user.setId(i);
        		user.setUserName("*testusername*" + i);
        		user.setPassWord("*testpassword*"+i);
        		user.setRealName("*testrealname*"+i);
        		list.add(user);
            }
        	userMapper.insertUser(list1);
            return true;
        }

UserMapper.xml  
foreach中的collection代表集合名称，比如list1。item代表遍历汇总的别名。

<insert id="insertUser" parameterType="org.spring.springboot.entity.User">
            insert into user(id,userName,passWord,realName) values 
            <foreach collection="list1" item="user" separator=",">
               (#{user.id},#{user.userName},#{user.passWord},#{user.realName}) 
            </foreach>
        </insert>

执行`http://localhost:8086/testBoot/insertUser`插入结果如下  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 9]

**参考链接如下：**  
[SpringBoot整合Mybatis完整详细版][SpringBoot_Mybatis]  
[SpringBoot之整合Mybatis（增，改，删）][SpringBoot_Mybatis 1]  
[解决eclipse maven工程中src/main/resources目录下创建的文件夹所显示样式不是文件夹，而是"包"图标样式的问题][eclipse maven_src_main_resources]  
[Java连接MySQL数据库8.0以上版本遇到的坑][springboot_MySQL]  
[运行springboot项目报错：Field userMapper in XX required a bean of type ‘xx’ that could not be found.][springboot_Field userMapper in XX required a bean of type _xx_ that could not be found.]  
[Springboot之application.properties的使用][Springboot_application.properties]

[Eclipse_Maven]: https://blog.csdn.net/nioqnw/article/details/87177475
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70]: /images/20230209/4ee7ec7c941f4e2ebc587da4b3f691c3.png
[springboot_MySQL]: https://blog.csdn.net/qq_40990854/article/details/83217115
[eclipse maven_src_main_resources]: https://blog.csdn.net/qq_36125733/article/details/77992402
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 1]: /images/20230209/85d8dd2aed094b16872e40d0cf0464fc.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20200718110439199.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ==,size_16,color_FFFFFF,t_70
[Caused by_ org.xml.sax.SAXParseException_ _ _update_ _ _resultType]: https://blog.csdn.net/weixin_44943631/article/details/103272321
[20200717190250277.png]: https://img-blog.csdnimg.cn/20200717190250277.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20200717190831508.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ==,size_16,color_FFFFFF,t_70
[Demo]: https://download.csdn.net/download/jike11231/12633746
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 4]: https://img-blog.csdnimg.cn/20200717190726376.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 5]: https://img-blog.csdnimg.cn/20200718110107657.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 6]: https://img-blog.csdnimg.cn/20200718110302905.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 7]: https://img-blog.csdnimg.cn/20200718110326950.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 8]: https://img-blog.csdnimg.cn/20210618142112598.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ_size_16_color_FFFFFF_t_70 9]: https://img-blog.csdnimg.cn/20210618142724355.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ppa2UxMTIzMQ==,size_16,color_FFFFFF,t_70
[SpringBoot_Mybatis]: https://blog.csdn.net/iku5200/article/details/82856621
[SpringBoot_Mybatis 1]: https://www.cnblogs.com/zhangchengzi/p/9662639.html
[springboot_Field userMapper in XX required a bean of type _xx_ that could not be found.]: https://blog.csdn.net/a600849155/article/details/81189412
[Springboot_application.properties]: https://blog.csdn.net/margin_0px/article/details/82998567