import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.methods.PostMethod;


public class HttpClientTest {

    private final static String REMOTE_FILE_URL = "http://202.120.96.77/dataViewPage/getFile.aspx?filename=GB-T 1.1-2000.pdf";

    private final static int BUFFER = 1024;

    public static void main(String[] args) {

        HttpClient client = new HttpClient();
        PostMethod httpGet = new PostMethod(REMOTE_FILE_URL);
        try {
            client.executeMethod(httpGet);

            InputStream in = httpGet.getResponseBodyAsStream();
            
            FileOutputStream out = new FileOutputStream(new File("E:\\GB-T 1.1-2000.pdf"));

            byte[] b = new byte[BUFFER];
            int len = 0;
            while ((len = in.read(b)) != -1) {
                out.write(b, 0, len);
            }
            in.close();
            out.close();

        } catch (HttpException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            httpGet.releaseConnection();
        }
        System.out.println("download, success!!");
    }
}

public static void main(String[] args) {

        HttpClient client = new HttpClient();
        PostMethod httpGet = new PostMethod(REMOTE_FILE_URL);
        try {
            client.executeMethod(httpGet);

            InputStream in = httpGet.getResponseBodyAsStream();
            
            FileOutputStream out = new FileOutputStream(new File("E:\\GB-T 1.1-2000.pdf"));

            byte[] b = new byte[BUFFER];
            int len = 0;
            while ((len = in.read(b)) != -1) {
                out.write(b, 0, len);
                out.flush();//注意要清空流
            }

        } catch (HttpException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try{
             in.close();
            }catch(Exception e){
             e.printStackTrace();
            }
            try{
             out.close();
            }catch(Exception e){
             e.printStackTrace();
            }            
            httpGet.releaseConnection();
        }
        System.out.println("download, success!!");
    }

------解决方案--------------------

探讨

out.flush();//注意要清空流


------解决方案--------------------

学习。。。

------解决方案--------------------

java + js