In java how to fix HTTP error 416 Requested Range Not Satisfiable? (While downloading web content from a web page)

问题

I am trying to download the html content of a web page and getting the 416 status. I found one solution which correctly improves the status code as 200 but still not downloading the proper content. I am very close but missing something. Please help.

Code with 416 status:

    public static void main(String[] args) {
        String URL="http://www.xyzzzzzzz.com.sg/";

        HttpClient client = new org.apache.commons.httpclient.HttpClient();
        org.apache.commons.httpclient.methods.GetMethod method = new org.apache.commons.httpclient.methods.GetMethod(URL);
        client.getHttpConnectionManager().getParams().setConnectionTimeout(AppConfig.CONNECTION_TIMEOUT);
        client.getHttpConnectionManager().getParams().setSoTimeout(AppConfig.READ_DATA_TIMEOUT);
        String html = null; InputStream ios = null;
        try {
            int statusCode = client.executeMethod(method);

            ios = method.getResponseBodyAsStream();
            html = IOUtils.toString(ios, "utf-8");
            System.out.println(statusCode);
        }catch (Exception e) {
            e.printStackTrace();
        } finally {
            if(ios!=null) {
                try {ios.close();} 
                catch (IOException e) {e.printStackTrace();}
            }
            if(method!=null) method.releaseConnection();
        }

        System.out.println(html);
    }

Code with 200 status (but htmlContent is not proper):

    public static void main(String[] args) {

        String URL="http://www.xyzzzzzzz.com.sg/";

        HttpClient client = new org.apache.commons.httpclient.HttpClient();
        org.apache.commons.httpclient.methods.GetMethod method = new org.apache.commons.httpclient.methods.GetMethod(URL);
        client.getHttpConnectionManager().getParams().setConnectionTimeout(AppConfig.CONNECTION_TIMEOUT);
        client.getHttpConnectionManager().getParams().setSoTimeout(AppConfig.READ_DATA_TIMEOUT);
        String html = null; InputStream ios = null;
        try {
            int statusCode = client.executeMethod(method);
            if(statusCode == HttpStatus.SC_REQUESTED_RANGE_NOT_SATISFIABLE) {
                method.setRequestHeader("User-Agent", "Mozilla/5.0");
                method.setRequestHeader("Accept-Ranges", "bytes=100-1500");
                statusCode = client.executeMethod(method);
            }
            ios = method.getResponseBodyAsStream();
            html = IOUtils.toString(ios, "utf-8");
            System.out.println(statusCode);
        }catch (Exception e) {
            e.printStackTrace();
        } finally {
            if(ios!=null) {
                try {ios.close();} 
                catch (IOException e) {e.printStackTrace();}
            }
            if(method!=null) method.releaseConnection();
        }

        System.out.println(html);
    }

回答1:

You can do this with a URL Connection.

Check this post

Using java.net.URLConnection to fire and handle HTTP requests

回答2:

Your first sample code works for me without problems, the second sample code works if I remove the set headers code block

if(statusCode == HttpStatus.SC_REQUESTED_RANGE_NOT_SATISFIABLE) {
    method.setRequestHeader("User-Agent", "Mozilla/5.0");
    method.setRequestHeader("Accept-Ranges", "bytes=100-1500");
    statusCode = client.executeMethod(method);
}

It's a bit strange, a LAN config issue maybe (firewall, proxy... etc), anyway HttpClient 3.1 is quite old, using httpclient 4.x from Apache HttpComponents

import org.apache.commons.io.IOUtils;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

public class Snippet {

    public static void main(String[] args) {

        String url = "http://www.jobstreet.com.sg/";
        HttpClient client = new DefaultHttpClient();
        HttpGet get = new HttpGet(url);
        try {
            HttpResponse res = client.execute(get);
            System.out.println(res.getStatusLine().getStatusCode());
            System.out.println(IOUtils.toString(res.getEntity().getContent()));
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            client.getConnectionManager().shutdown();
        }
    }
}

works as expected.

Try with HttpClient 4, if you still getting the same error then the problem is not in your code.

来源：https://stackoverflow.com/questions/20855558/in-java-how-to-fix-http-error-416-requested-range-not-satisfiable-while-downlo