httpclient重定向之後取得網址資訊範例

複製代碼代碼如下:

import org.apache.http.HttpEntity;

import org.apache.http.HttpHost;

import org.apache.http.HttpResponse;

import org.apache.http.client.HttpClient;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.client.methods.HttpUriRequest;

import org.apache.http.entity.ContentType;

import org.apache.http.impl.client.DefaultHttpClient;

import org.apache.http.protocol.BasicHttpContext;

import org.apache.http.protocol.ExecutionContext;

import org.apache.http.protocol.HttpContext;

import org.apache.http.util.EntityUtils;

public class HttpClientDemo {

/**

* 取得重定向之後的網址信息

* @see HttpClient預設會自動處理客戶端重新導向

* @see 即訪問網頁A後,假設被重定向到了B網頁,那麼HttpClient將自動返回B網頁的內容

* @see 若想取得B網頁的位址,就需要藉助HttpContext物件,HttpContext其實是客戶端用來在多次要求回應的互動中,保持狀態資訊的

* @see 我們自己也可以利用HttpContext來存放一些我們需要的資訊,以便下次請求的時候能夠取出這些資訊來使用

*/

public static void getRedirectInfo(){

HttpClient httpClient = new DefaultHttpClient();

HttpContext httpContext = new BasicHttpContext();

HttpGet httpGet = new HttpGet("http://127.0.0.1:8088/blog/main.jsp");

try {

//將HttpContext物件當作參數傳給execute()方法,則HttpClient會把請求回應互動過程中的狀態資訊儲存在HttpContext中

HttpResponse response = httpClient.execute(httpGet, httpContext);

//取得重定向之後的主機位址資訊,即"http://127.0.0.1:8088"

HttpHost targetHost = (HttpHost)httpContext.getAttribute(ExecutionContext.HTTP_TARGET_HOST);

//取得實際的請求物件的URI,即重定向之後的"/blog/admin/login.jsp"

HttpUriRequest realRequest = (HttpUriRequest)httpContext.getAttribute(ExecutionContext.HTTP_REQUEST);

System.out.println("主機位址:" + targetHost);

System.out.println("URI訊息:" + realRequest.getURI());

HttpEntity entity = response.getEntity();

if(null != entity){

System.out.println("回應內容:" + EntityUtils.toString(entity, ContentType.getOrDefault(entity).getCharset()));

EntityUtils.consume(entity);

}

} catch (Exception e) {

e.printStackTrace();

}finally{

httpClient.getConnectionManager().shutdown();

}

}

}