String url="<img src="http://p1.qhimg.com/d/_hao360/weather/4.png" title="雷阵雨"> ";

if(!weather_pic.equals("")) { if(weather_pic.indexOf("src")>-1) {       

   url=url.substring(url.indexOf("src")+5,url.indexOf("png")+3);

  }

}
截取之后:url="http://p1.qhimg.com/d/_hao360/weather/4.png";

 

截取url最后一个/后、点之前的字符String info_id = url.substring(url.lastIndexOf("/")+1,url.lastIndexOf("."));

截取之后:4