检测url是否可用

public static Boolean testUrl(String urlString){    URL url;    try {        url = new URL(urlString);        InputStream in = url.openStream();        System.out.println("连接可用");        return true;    } catch (Exception e1) {        System.out.println("连接打不开!");        System.out.println(e1);        url = null;        return false;    }}public static void main(String[] args) {    Boolean aBoolean = testUrl("http://www.baidu.com");    System.out.println("测试是否可用"+aBoolean);}