1. Properties类表示了一个持久的属性集。Properties 可保存在流中或从流中加载。可用来读取和设置配置文件如.xml文件，.properties文件
2. 实例如下：
3. package test;   
4.   
5. import java.io.File;   
6. import java.io.FileInputStream;   
7. import java.io.FileNotFoundException;   
8. import java.io.FileOutputStream;   
9. import java.io.IOException;   
10. import java.io.InputStream;   
11. import java.util.InvalidPropertiesFormatException;   
12. import java.util.Properties;   
13.   
14. public class TestProperties {   
15.     public static final String DB_DRIVERNAME="driverName";   
16.     public static final String DB_URL="url";   
17.     public static final String DB_USERNAME="username";   
18.     public static final String DB_PWD="pwd";   
19.     public static final String SYSTEMFILE_PROPERTIES="webapps/WEB-INF/classes/test/tp.properties";    //路径视实际情况而定
20.     public static final String SYSTEMFILE_PROPERTIES2="webapps/WEB-INF/classes/test/tp2.properties";   
21.     public static final String SYSTEMFILE_XML="webapps/WEB-INF/classes/test/tp.xml";   
22.     public static final String SYSTEMFILE_XML2="webapps/WEB-INF/classes/test/tp2.xml";   
23.     protected Properties properties=null;   
24.     public TestProperties(){   
25.         //this(SYSTEMFILE_PROPERTIES);   
26.     }   
27.     private TestProperties(String fileName){   
28.            
29.         //loadProperties(SYSTEMFILE_PROPERTIES);   
30.            
31.         this.loadXML(SYSTEMFILE_XML);   
32.     }   
33.     //解析properties文件   
34.     public void loadProperties(String fileName){   
35.         File file=new File(fileName);   
36.         InputStream in=null;   
37.         properties=new Properties();   
38.   
39.         if(file.exists()){   
40.             try {   
41.                 in=new FileInputStream(file);   
42.                 properties.load(in);   
43.             } catch (FileNotFoundException e) {   
44.   
45.                 e.printStackTrace();   
46.             } catch (IOException e) {
47.                 e.printStackTrace();   
48.             }finally{   
49.                 if(in!=null){   
50.                     try {   
51.                         in.close();   
52.                     } catch (IOException e) {   
53.  
54.                         e.printStackTrace();   
55.                     }   
56.                     in=null;   
57.                 }   
58.             }   
59.   
60.         }else{   
61.             System.out.println("文件不存在！");   
62.         }   
63.   
64.     }   
65.        
66.     //解析XML文件   
67.     public void loadXML(String filename){   
68.         File file=new File(SYSTEMFILE_XML);   
69.         InputStream in=null;   
70.         properties=new Properties();   
71.            
72.         if(file.exists()){   
73.             try {   
74.                 in=new FileInputStream(file);   
75.                 properties.loadFromXML(in);   
76.             } catch (FileNotFoundException e) {   
77.                 e.printStackTrace();   
78.             } catch (InvalidPropertiesFormatException e) {   
79.  
80.                 e.printStackTrace();   
81.             } catch (IOException e) {   
82.                 if(in!=null){   
83.                     try {   
84.                         in.close();   
85.                     } catch (IOException e1) {   
86.                         e1.printStackTrace();   
87.                     }   
88.                     in=null;   
89.                 }   
90.                 e.printStackTrace();   
91.             }   
92.                
93.         }else{   
94.             System.out.println("文件不存在！");   
95.         }   
96.     }   
97.        
98.     //设置properties文件   
99.     public void storeProperties(){   
100.         properties=new Properties();   
101.         properties.setProperty(DB_DRIVERNAME, "oracle.jdbc.driver.OracleDriver");   
102.         properties.setProperty(DB_URL, "jdbc:oracle:thin@127.0.0.1:1521:orcl");   
103. //      properties.setProperty(DB_USERNAME, "test2");   
104. //      properties.setProperty(DB_PWD, "test2");   
105.         File file=new File(SYSTEMFILE_PROPERTIES2);   
106.         FileOutputStream fo=null;   
107.  
108.         try {   
109.             fo=new FileOutputStream(file);   
110.             properties.store(fo, "test");   
111.         } catch (FileNotFoundException e) {   
112.             e.printStackTrace();   
113.         } catch (IOException e) {    
114.             e.printStackTrace();   
115.         }finally{   
116.             if(fo!=null){   
117.                 try {   
118.                     fo.close();   
119.                 } catch (IOException e) {  
120.                     e.printStackTrace();   
121.                 }   
122.                 fo=null;   
123.             }   
124.         }   
125.            
126.     }   
127.        
128.     //设置XML文件   
129.     public void storeXML(){   
130.         properties=new Properties();   
131.         properties.setProperty(DB_DRIVERNAME, "oracle.jdbc.driver.OracleDriver");   
132.         properties.setProperty(DB_URL, "jdbc:oracle:thin@127.0.0.1:1521:orcl");   
133.         properties.setProperty(DB_USERNAME, "test2");   
134.         properties.setProperty(DB_PWD, "test2");   
135.         File file=new File(SYSTEMFILE_XML2);   
136.         FileOutputStream fo=null;   
137.         try {   
138.             fo=new FileOutputStream(file);   
139.             properties.storeToXML(fo, "conn");   
140.         } catch (FileNotFoundException e) {  
141.             e.printStackTrace();   
142.         } catch (IOException e) {  
143.             e.printStackTrace();   
144.         }finally{   
145.             if(fo!=null){   
146.                 try {   
147.                     fo.close();   
148.                 } catch (IOException e) {  
149.                     e.printStackTrace();   
150.                 }   
151.                 fo=null;   
152.             }   
153.         }   
154.     }   
155.     public String getDrivername(){   
156.         return (String)properties.getProperty(DB_DRIVERNAME);   
157.     }   
158.     public String getURL(){   
159.   
160.         return (String)properties.getProperty(DB_URL);   
161.     }   
162.     public String getName(){   
163.         return (String)properties.getProperty(DB_USERNAME);   
164.     }   
165.     public String getPWD(){   
166.         return (String)properties.getProperty(DB_PWD);   
167.     }   
168.   
169.     public static void main(String args[]){   
170.         TestProperties tp=new TestProperties();   
171. //      System.out.println(tp.getDrivername());   
172. //      System.out.println(tp.getURL());   
173. //      System.out.println(tp.getName());   
174. //      System.out.println(tp.getPWD());   
175.         //tp.storeXML();   
176.         tp.storeProperties();   
177.   
178.     }   
179. }  
181. tp.properties：
182. url=jdbc:oracle:thin@127.0.0.1:1521:orcl
     driverName=oracle.jdbc.driver.OracleDriver
     username=123
     pwd=123
183. tp.xml
184. <?xml version="1.0" encoding="UTF-8" standalone="no"?>
     <!DOCTYPE properties SYSTEM "">
     <properties>
     <comment>Hi</comment>
     <entry key="url">jdbc:oracle:thin@127.0.0.1:1521:orcl</entry>
     <entry key="driverName">oracle.jdbc.driver.OracleDriver</entry>
     <entry key="username">123</entry>
     <entry key="pwd">123</entry>
     </properties>