1 import java.util.Properties;
2
3 public class GetJVM {
4     public static void main(String[] args) {
5         Properties pps = System.getProperties();
6         pps.list(System.out);
7     }
8 }

name=jack
Weight=60
Height=175

 1 public class getProperties {
2     public static void main(String[] args) throws FileNotFoundException, IOException {
3         Properties pps = new Properties();
4         pps.load(new FileInputStream("Test.properties"));
5         Enumeration enum1 = pps.propertyNames();//得到配置文件的名字
6         while(enum1.hasMoreElements()) {
7             String strKey = (String) enum1.nextElement();
8             String strValue = pps.getProperty(strKey);
9             System.out.println(strKey + "=" + strValue);
10         }
11     }
12 }

 1 //关于Properties类常用的操作
2 public class TestProperties {
3     //根据Key读取Value
4     public static String GetValueByKey(String filePath, String key) {
5         Properties pps = new Properties();
6         try {
7             InputStream in = new BufferedInputStream (new FileInputStream(filePath));
8             pps.load(in);
9             String value = pps.getProperty(key);
10             System.out.println(key + " = " + value);
11             return value;
12
13         }catch (IOException e) {
14             e.printStackTrace();
15             return null;
16         }
17     }
18
19     //读取Properties的全部信息
20     public static void GetAllProperties(String filePath) throws IOException {
21         Properties pps = new Properties();
22         InputStream in = new BufferedInputStream(new FileInputStream(filePath));
23         pps.load(in);
24         Enumeration en = pps.propertyNames(); //得到配置文件的名字
25
26         while(en.hasMoreElements()) {
27             String strKey = (String) en.nextElement();
28             String strValue = pps.getProperty(strKey);
29             System.out.println(strKey + "=" + strValue);
30         }
31
32     }
33
34     //写入Properties信息
35     public static void WriteProperties (String filePath, String pKey, String pValue) throws IOException {
36         Properties pps = new Properties();
37
38         InputStream in = new FileInputStream(filePath);
39         //从输入流中读取属性列表（键和元素对）
40         pps.load(in);
41         //调用 Hashtable 的方法 put。使用 getProperty 方法提供并行性。
42         //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。
43         OutputStream out = new FileOutputStream(filePath);
44         pps.setProperty(pKey, pValue);
45         //以适合使用 load 方法加载到 Properties 表中的格式，
46         //将此 Properties 表中的属性列表（键和元素对）写入输出流
47         pps.store(out, "Update " + pKey + " name");
48     }
49
50     public static void main(String [] args) throws IOException{
51         //String value = GetValueByKey("Test.properties", "name");
52         //System.out.println(value);
53         //GetAllProperties("Test.properties");
54         WriteProperties("Test.properties","long", "100");
55     }
56 }