org.apache.http.ProtocolException：未指定目标主机

Posted 2023-03-31

【中文标题】org.apache.http.ProtocolException：未指定目标主机

【英文标题】：org.apache.http.ProtocolException: Target host is not specified

【发布时间】：2014-07-27 21:20:23

【问题描述】：

我编写了一个简单的 httprequest/response 代码，但出现以下错误。我在类路径中引用了 httpclient、httpcore、common-codecs 和 common-logging。我对java很陌生，不知道这里发生了什么。请帮我。

代码：

import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.HttpResponse;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.Header;
import org.apache.http.HttpHeaders;

public class UnshorteningUrl 

    public static void main(String[] args) throws Exception
               
        HttpGet request=null;
        HttpClient client = HttpClientBuilder.create().build();         

        try 
            request = new HttpGet("trib.me/1lBFzSi");
            HttpResponse httpResponse=client.execute(request);

            Header[] headers = httpResponse.getHeaders(HttpHeaders.LOCATION);
           // Preconditions.checkState(headers.length == 1);
            String newUrl = headers[0].getValue();          
            System.out.println("new url" + newUrl);         
         catch (IllegalArgumentException e) 
            // TODO: handle exception
        finally 
            if (request != null) 
                request.releaseConnection();
                       
        
    

错误：

Exception in thread "main" org.apache.http.client.ClientProtocolException
    at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:186)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:106)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:57)
    at UnshorteningUrl.main(UnshorteningUrl.java:26)
Caused by: org.apache.http.ProtocolException: Target host is not specified
    at org.apache.http.impl.conn.DefaultRoutePlanner.determineRoute(DefaultRoutePlanner.java:69)
    at org.apache.http.impl.client.InternalHttpClient.determineRoute(InternalHttpClient.java:124)
    at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:183)
    ... 4 more

【参考方案1】：

错误信息有点误导。您提供的值不代表完整的 URI

request = new HttpGet("trib.me/1lBFzSi");

它缺少协议。

只需提供完整的 URI

request = new HttpGet("http://trib.me/1lBFzSi");

【参考方案2】：

此错误可能是由于错误的 url 造成的。 检查网址：

缺少协议； url参数编码；

【参考方案3】：

就我而言，我解决了在开头添加 / 的问题： request = new HttpGet("/trib.me/1lBFzSi");