java设计模式

 

Env 单例模式简单示例： package com.accp.dao; import java.util.Properties; import java.io.InputStream; public final class Env extends Properties{ private static Env env = null; public static Env getEnv(){ if (env != null){ return env; }else{ getSynEnv(); return env; } } private synchronized static void getSynEnv(){ if(env == null){ env = new Env(); } } private Env(){ InputStream is = this.getClass().getResourceAsStream("/db.properties"); try{ load(is); }catch(Exception ex){ System.out.print("找不到 文件"); } } }