import java.util.Properties;

public class ReadJVM {
 public static void main(String[] args) {
  Properties pps = System.getProperties();
  pps.list(System.out);
 }
}

name=JJ
Weight=4444
Height=3333

public class getProperties {
 public static void main(String[] args) throws FileNotFoundException, IOException {
  Properties pps = new Properties();
  pps.load(new FileInputStream("Test.properties"));
  Enumeration enum1 = pps.propertyNames();//得到配置文件的名字
  while(enum1.hasMoreElements()) {
   String strKey = (String) enum1.nextElement();
   String strValue = pps.getProperty(strKey);
   System.out.println(strKey + "=" + strValue);
  }
 }
}

//关于Properties类常用的操作
public class TestProperties {
 //根据Key读取Value
 public static String GetValueByKey(String filePath, String key) {
  Properties pps = new Properties();
  try {
   InputStream in = new BufferedInputStream (new FileInputStream(filePath)); 
   pps.load(in);
   String value = pps.getProperty(key);
   System.out.println(key + " = " + value);
   return value;
   
  }catch (IOException e) {
   e.printStackTrace();
   return null;
  }
 }
 
 //读取Properties的全部信息
 public static void GetAllProperties(String filePath) throws IOException {
  Properties pps = new Properties();
  InputStream in = new BufferedInputStream(new FileInputStream(filePath));
  pps.load(in);
  Enumeration en = pps.propertyNames(); //得到配置文件的名字
  
  while(en.hasMoreElements()) {
   String strKey = (String) en.nextElement();
   String strValue = pps.getProperty(strKey);
   System.out.println(strKey + "=" + strValue);
  }
  
 }
 
 //写入Properties信息
 public static void WriteProperties (String filePath, String pKey, String pValue) throws IOException {
  Properties pps = new Properties();
  
  InputStream in = new FileInputStream(filePath);
  //从输入流中读取属性列表（键和元素对） 
  pps.load(in);
  //调用 Hashtable 的方法 put。使用 getProperty 方法提供并行性。 
  //强制要求为属性的键和值使用字符串。返回值是 Hashtable 调用 put 的结果。
  OutputStream out = new FileOutputStream(filePath);
  pps.setProperty(pKey, pValue);
  //以适合使用 load 方法加载到 Properties 表中的格式， 
  //将此 Properties 表中的属性列表（键和元素对）写入输出流 
  pps.store(out, "Update " + pKey + " name");
 }
 
 public static void main(String [] args) throws IOException{
  //String value = GetValueByKey("Test.properties", "name");
  //System.out.println(value);
  //GetAllProperties("Test.properties");
  WriteProperties("Test.properties","long", "212");
 }
}

#Update long name
#Sun Feb 23 18:17:16 CST 2014
name=JJ
Weight=4444
long=212
Height=3333