改变时间显示

<pre name="code" class="java">改变时间显示

static SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    /**
     * 改变时间显示
     * @param str
     * @return
     */
	public static String changeTime(String str){
	  
	       java.util.Date now;
	    try {
	       now = new Date();
	       java.util.Date date=df.parse(str);
	       long l=now.getTime()-date.getTime();
			long day=l/(24*60*60*1000);
	       long hour=(l/(60*60*1000)-day*24);
	       long min=((l/(60*1000))-day*24*60-hour*60);
	       long s=(l/1000-day*24*60*60-hour*60*60-min*60);
	        
	       StringBuffer sb = new StringBuffer();
	       if(day > 0){
	    	   sb.append(day+"天");  
	    	   if(day<4){
	    		   return sb.toString()+"前";   
	    	   }
	    	   return str;
	       }
	       if(hour > 0 ){
	    	   sb.append(hour+"小时"+"前");
	    	   return sb.toString();
	       }
	       if(min > 0 ){
	    	   sb.append(min+"分钟");
	    	   return sb.toString()+"前";
	       }else{
	    	   sb.append(s+"秒 前");
	       }
	           
	     
//	       System.out.println(sb.toString());
	       return sb.toString();
	    } catch (Exception e) {
	        // TODO Auto-generated catch block
	    	return ""+str;
	    }
	 
	}