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 {

 /**
  * 获取重定向之后的网址信息
  * @see HttpClient缺省会自动处理客户端重定向
  * @see 即访问网页A后,假设被重定向到了B网页,那么HttpClient将自动返回B网页的内容
  * @see 若想取得B网页的地址,就需要借助HttpContext对象,HttpContext实际上是客户端用来在多次请求响应的交互中,保持状态信息的
  * @see 我们自己也可以利用HttpContext来存放一些我们需要的信息,以便下次请求的时候能够取出这些信息来使用
  */
 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 {
   //将HttpContext对象作为参数传给execute()方法,则HttpClient会把请求响应交互过程中的状态信息存储在HttpContext中
   HttpResponse response = httpClient.execute(httpGet, httpContext);
   //获取重定向之后的主机地址信息,即"http://127.0.0.1:8088"
   HttpHost targetHost = (HttpHost)httpContext.getAttribute(ExecutionContext.HTTP_TARGET_HOST);
   //获取实际的请求对象的URI,即重定向之后的"/blog/admin/login.jsp"
   HttpUriRequest realRequest = (HttpUriRequest)httpContext.getAttribute(ExecutionContext.HTTP_REQUEST);
   System.out.println("主机地址:" + targetHost);
   System.out.println("URI信息:" + realRequest.getURI());
   HttpEntity entity = response.getEntity();
   if(null != entity){
    System.out.println("响应内容:" + EntityUtils.toString(entity, ContentType.getOrDefault(entity).getCharset()));
    EntityUtils.consume(entity);
   }
  } catch (Exception e) {
   e.printStackTrace();
  }finally{
   httpClient.getConnectionManager().shutdown();
  }
 }
}