单例案例

package com.icss.dao;

import java.io.InputStream;
import java.util.Properties;

public class Env extends Properties{
 private static final long serialVersionUID = 1L;

 private static Env instance;

 public static Env getInstance() {
  if (instance != null) {
   return instance;
  } else {
   makeInstance();
   return instance;
  }
 }

 private static synchronized void makeInstance() {
  if (instance == null) {
   instance = new Env();
  }
 }

 private Env(){
  InputStream is = getClass().getResourceAsStream("/db.properties");
  try {
   load(is);
  } catch (Exception e) {
   System.err.println("错误：没有读取属性文件，请确认db.property文件是否存在。");
   return;
  }
 }

}

 

 

用于读属性文件db.perperty