如何在java中获取响应代码

时间:2013-10-04 09:04:58

标签: java

我想在我的程序中使用响应代码 请告诉我以下代码中的错误

  public class Main{
      public static void main(String args[]) throws Exception {
        URL url = new URL("http://www.google.com");
        HttpURLConnection httpCon = openConnection();


        System.out.println("Response code is " + httpCon.getResponseCode());
     }
    }

5 个答案:

答案 0 :(得分:2)

public class Main{
  public static void main(String args[]) throws Exception {
    URL url = new URL("http://www.google.com");
    HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();


    System.out.println("Response code is " + httpCon.getResponseCode());
 }
}

答案 1 :(得分:1)

错误很明显。

openConnection()URL类的一种方法,在您的班级中未定义。您必须使用之前创建的URL类对象。

调用openConnection()方法必须是这样的 -

url.openConnection()它返回一个URLConnection对象,您必须将此对象强制转换为HttpURLConnection

答案 2 :(得分:0)

该问题的

原因是编译器告诉类构造函数(URL)和方法(openConnection ..)抛出异常(在signatures中定义)并采取一些必要的步骤。

您有两个选择:

Throw来自主方法的已检查异常。

public static void main(String[] args) throws IOException {
            URL url = new URL("http://www.google.com");
            HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();
                System.out.println("Response code is " +
                                              httpCon.getResponseCode());
             }

使用Exception

抓住try catch block.
public static void main(String[] args) {
        URL url;
        HttpURLConnection httpCon;
        try {
            url = new URL("http://www.google.com");
            httpCon = (HttpURLConnection) url.openConnection();
            System.out.println("Response code is " + httpCon.getResponseCode());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

答案 3 :(得分:0)

你忘了放url 将其更改为HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();

package naveed.workingfiles;

import java.net.HttpURLConnection;
import java.net.URL;

public class Url {

    public static void main(String args[]) throws Exception {
        URL url = new URL("http://www.google.com");
        HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();

        System.out.println("Response code is " + httpCon.getResponseCode());
    }
}

答案 4 :(得分:0)

尝试将对象强制转换为HttpURLConnection

public class Main{
  public static void main(String args[]) throws Exception {
    URL url = new URL("http://www.google.com");
    //Cast the object to  HttpURLConnection
    HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();
    System.out.println("Response code is " + httpCon.getResponseCode());
 }
}