InputStream inStream = TestProperties.class.getClassLoader().getResourceAsStream("demo.properties"); 
//通過當前類加載器的getResourceAsStream方法獲取
//TestProperties當前類名；TestProperties.class.取得當前對象所屬的Class對象； getClassLoader()：取得該Class對象的類裝載器

InputStream in = ClassLoader.getSystemResourceAsStream("filePath");

InputStream inStream = new FileInputStream(new File("filePath")); //從文件獲取
InputStream in = context.getResourceAsStream("filePath");     //在servlet中，可以通過context來獲取InputStream
InputStream inStream = new URL("path").openStream(); 　　　　　　　　　　 //通過URL來獲取

Properties pro = new Properties();    　　　　　　　　　　　　　　　//實例化一個Properties對象
InputStream inStream = new FileInputStream("demo.properties");  　　　//獲取屬性文件的文件輸入流
pro.load(nStream);
inStream.close();

FileOutputStream outStream = new FileOutputStream("demo.properties");
pro.store(outStream,"Comment");
outStream.close();

ResourceBundle resource = ResourceBundle.getBundle("com/xiang/demo");//emo為屬性文件名，放在包com.xiang下，如果是放在src下，直接用test即可 
ResourceBundle resource1 = new PropertyResourceBundle(inStream);  
String value = resource.getString("name"); 

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;

/**
 * Java中Preperties配置文件工具類
 * @author shu
 *
 */
public class PropsUtil {
  private String path = "";
  private Properties properties ;
  
  /**
   * 默認構造函數
   */
  public PropsUtil() {}
  
  /**
   * 構造函數
   * @param path 傳入Properties地址值
   */
  public PropsUtil(String path) {
    this.path = path;
  }
  
  /**
   * 加載properties文件
   * @return 返回讀取到的properties對象
   */
  public Properties loadProps(){
    InputStream inStream = ClassLoader.getSystemResourceAsStream(path);    
    try {
      if(inStream==null)
        throw new FileNotFoundException(path + " file is not found");
      properties = new Properties();
      properties.load(inStream);
      inStream.close();
    } catch (IOException e) {
      e.printStackTrace();
    }
    return properties;
  }
  
  /**
   * 將配置寫入到文件
   */
  public void writeFile(){
    // 獲取文件輸出流
    try {
      FileOutputStream outputStream = new FileOutputStream( new File(ClassLoader.getSystemResource(path).toURI()));
      properties.store(outputStream, null);
      outputStream.close();
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
  
  /**
   * 通過關鍵字獲取值
   * @param key
   * @return 返回對應的字符串，如果無，返回null
   */
  public String getValueByKey(String key) {
    if(properties==null)
      properties = loadProps();
    String val = properties.getProperty(key.trim());
    return val;
  }
  
  /**
   * 通過關鍵字獲取值
   * @param key 需要獲取的關鍵字
   * @param defaultValue 若找不到對應的關鍵字時返回的值
   * @return 返回找到的字符串
   */
  public String getValueByKey(String key,String defaultValue){
    if(properties==null)
      properties = loadProps();
    return properties.getProperty(key, defaultValue);
  }
  
  /**
   * 獲取Properties所有的值
   * @return 返回Properties的鍵值對
   */
  public Map<String, String> getAllProperties() {
    if(properties==null)
      properties = loadProps();
    Map<String, String> map = new HashMap<String, String>();
    // 獲取所有的鍵值
    Iterator<String> it=properties.stringPropertyNames().iterator();
    while(it.hasNext()){
      String key=it.next();
      map.put(key, properties.getProperty(key));
    }
    /*Enumeration enumeration = properties.propertyNames();
    while (enumeration.hasMoreElements()) {
      String key = (String) enumeration.nextElement();
      String value = getValueByKey(key);
      map.put(key, value);
    }*/
    return map;
  }

  /**
   * 往Properties寫入新的鍵值且保存
   * @param key 對應的鍵
   * @param value 對應的值
   */
  public void addProperties(String key, String value) {
    if(properties==null)
      properties = loadProps();
    properties.setProperty(key, value);
    try {
      writeFile();
    } catch (Exception e) {
      throw new RuntimeException("write fail");
    }
  }
  
  /**
   * 更新配置文件
   * @param key 對應的鍵
   * @param value 對應的值
   */
   public void update(String key,String value){
     if(properties==null)
      properties = loadProps();
     if(properties.containsKey(key))
       properties.replace(key, value);
    try {
      writeFile();
    } catch (Exception e) {
      throw new RuntimeException("write fail");
    }
   }
   
   /**
   * 刪除某一鍵值對
   * @param key
   */
   public void deleteByKey(String key){
     if(properties==null)
      properties = loadProps();
     if(!properties.containsKey(key))
       throw new RuntimeException("not such key");
     properties.remove(key);
     try {
      writeFile();
     } catch (Exception e) {
      throw new RuntimeException("write fail");
    }
   }
   
   /**
   * 設置path值
   * @param path
   */
   public void setPath(String path){
     this.path = path;
   }
}