apache http客户端java程序出错

Question

我有一个简单程序的问题，使用'apache http client（4.5.2 version）'从url获取数据。

请在下面找到代码和错误：

public static void main(String[] args) throws Exception {
        String username = "user";
        String password = "pwd";
        String urlString = "xyz.com?a=b&c=d";

        org.apache.http.client.HttpClient client = HttpClientBuilder.create().build();
        HttpGet request = new HttpGet(urlString);
        org.apache.http.auth.UsernamePasswordCredentials creds = new org.apache.http.auth.UsernamePasswordCredentials(
                username, password);
        request.addHeader(new BasicScheme().authenticate(creds, request));

        HttpResponse response = client.execute(request);
        System.out.println("Response Code : " + response.getStatusLine().getStatusCode());

        BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
        StringBuffer result = new StringBuffer();
        String line = "";
        while ((line = rd.readLine()) != null) {
            System.out.println(line);
            result.append(line);
        }
    }

错误：

<Error><Code>InvalidArgument</Code><Message>Only one auth mechanism allowed; only the X-Amz-Algorithm query parameter, Signature query string parameter or the Authorization header should be specified</Message>

能否请你帮忙 ？

Answer 1

我没有遇到上面的错误，但是在给定的开头添加“http：//”后，我能够运行此代码示例而没有错误

String urlString = "xyz.com?a=b&c=d";