Java 获取网络302重定向URL的方法

方法1：

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

import org.junit.Assert;
import org.junit.Test;

public class GetRedirectUrlTest {
 @Test
 public void test_getRedirectUrl() throws Exception {
   String url="http://www.baidu.com/link?url=ByBJLpHsj5nXx6DESXbmMjIrU5W4Eh0yg5wCQpe3kCQMlJK_RJBmdEYGm0DDTCoTDGaz7rH80gxjvtvoqJuYxK";
   String expectUrl="http://www.zhihu.com/question/20583607/answer/16597802";
   String redictURL = getRedirectUrl(url);
   Assert.assertEquals(expectUrl, redictURL);
 }

/**
  * 获取重定向地址
  * @param path
  * @return
  * @throws Exception
  */
 private String getRedirectUrl(String path) throws Exception {
   HttpURLConnection conn = (HttpURLConnection) new URL(path)
       .openConnection();
   conn.setInstanceFollowRedirects(false);
   conn.setConnectTimeout(5000);
   return conn.getHeaderField("Location");
 }
}

方法2：

/**
  * 处理跳转链接，获取重定向地址
  * @param url  源地址
  * @return   目标网页的绝对地址
  */
 public String getAbsUrl(String url){
   CloseableHttpClient httpclient = HttpClients.createDefault();
   HttpClientContext context = HttpClientContext.create();
   HttpGet httpget = new HttpGet(url);
   CloseableHttpResponse response = null;
   String absUrl = null;
   try {
     response = httpclient.execute(httpget, context);
     HttpHost target = context.getTargetHost();
     List<URI> redirectLocations = context.getRedirectLocations();
     URI location = URIUtils.resolve(httpget.getURI(), target, redirectLocations);
     System.out.println("Final HTTP location: " + location.toASCIIString());
     absUrl = location.toASCIIString();    
   }catch(IOException e){
     e.printStackTrace();
   }catch (URISyntaxException e) {    
     e.printStackTrace();
   }finally {
     try {
       httpclient.close();
       response.close();
     } catch (IOException e) {        
       e.printStackTrace();
     }
   }
   return absUrl;
 }

来源：https://www.cnblogs.com/fnlingnzb-learner/p/11429834.html