public class Mytest   
public static void readFile(String fileName) {//传入参数fileName是要读取的资源文件的文件名如(file.properties)  
        InputStream in = null;  
        Properties pros = new Properties();  
        try {  
            if (null != fileName) {  
//前提是资源文件必须和Mytest类在同一个包下  
        in = Mytest.class.getResourceAsStream(fileName);  
//得到当前类的路径，并把资源文件名作为输入流  
                pros.load(in);  
Enumeration en = pros.propertyNames();//得到资源文件中的所有key值  
        while (en.hasMoreElements()) {  
    String key = (String) en.nextElement();  
System.out.println("key=" + key + " value=" + pros.getProperty(key));  
//输出资源文件中的key与value值  
                }  
            }  
        } catch (IOException e) {  
            e.printStackTrace();  
            System.out.println("读取资源文件出错");  
        } finally {  
            try {  
            if (null != in) {  
                in.close();  
                }  
            } catch (IOException e) {  
                e.printStackTrace();  
                System.out.println("关闭流失败");  
            }  
        }  
  
    }  

import java.util.MissingResourceException;  
import java.util.ResourceBundle;  
  
public class Messages {  
    private static final String BUNDLE_NAME = "com.xxx.cs.mm.service.messages"; //messages.properties文件和Messages类在同一个包下,包名：com.xxx.cs.mm.service  
  
    private static final ResourceBundle RESOURCE_BUNDLE = ResourceBundle.getBundle(BUNDLE_NAME);  
  
    private Messages() {  
    }  
  
    public static String getString(String key) {  
        try {  
            return RESOURCE_BUNDLE.getString(key);  
        } catch (MissingResourceException e) {  
            return ‘!‘ + key + ‘!‘;  
        }  
    }  
}