1.将xx.properties文件放置在src/main/resources/config目录下（config是自己建的目录）

2. 通过ApplicationHome类获取target路径

 ApplicationHome applicationHome = new ApplicationHome(this.getClass());String path = applicationHome.getSource().getParent();

3.拼接字符串的方式，得到xx.properties文件路径（我的路径是在target/classes/config目录下。）

   String realPath = path + "/classes/config/";

** 4.通过读取文件**

           File file = new File(realPath + "xx.properties");InputStream inputStream = new FileInputStream(file);properties.load(inputStream);

5.用key值匹配value的值；

    String key  = "123";String value= properties.getProperty(key);

6.完整代码：

 private static Properties properties = new Properties();{ApplicationHome applicationHome = new ApplicationHome(this.getClass());String path = applicationHome.getSource().getParent();String realPath = path + "/classes/config/";try {File file = new File(realPath + "xx.properties");//将xx替换为自己的文件件InputStream inputStream = new FileInputStream(file);properties.load(inputStream);} catch (IOException e) {e.printStackTrace();}}String key  = "123";String value= properties.getProperty(key);System.out.print("通过key获取的value的值是"+value);