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);