我有一个可以从https服务器下载文件的类。当我运行它时，它返回很多错误。我的证书似乎有问题。是否可以忽略客户端服务器认证？如果是这样，怎么办？

package com.da;

import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.CharBuffer;
import java.util.concurrent.Future;

import org.apache.http.HttpResponse;
import org.apache.http.client.utils.URIUtils;
import org.apache.http.impl.nio.client.DefaultHttpAsyncClient;
import org.apache.http.nio.IOControl;
import org.apache.http.nio.client.HttpAsyncClient;
import org.apache.http.nio.client.methods.AsyncCharConsumer;
import org.apache.http.nio.client.methods.HttpAsyncGet;
import org.apache.http.nio.client.methods.HttpAsyncPost;

public class RSDDownloadFile {
    static FileOutputStream fos;

    public void DownloadFile(String URI, String Request) throws Exception
    {
        java.net.URI uri = URIUtils.createURI("https", "176.66.3.69:6443", -1, "download.aspx",
                "Lang=EN&AuthToken=package", null);
        System.out.println("URI Query: " + uri.toString());

        HttpAsyncClient httpclient = new DefaultHttpAsyncClient();
        httpclient.start();
        try {
            Future<Boolean> future = httpclient.execute(
                    new HttpAsyncGet(uri),
                    new ResponseCallback(), null);

            Boolean result = future.get();
            if (result != null && result.booleanValue()) {
                System.out.println("\nRequest successfully executed");
            } else {
                System.out.println("Request failed");
            }              
        } 
        catch(Exception e){
            System.out.println("[DownloadFile] Exception: " + e.getMessage());
        }
        finally {
            System.out.println("Shutting down");
            httpclient.shutdown();
        }
        System.out.println("Done");  

    }

    static class ResponseCallback extends AsyncCharConsumer<Boolean> {

        @Override
        protected void onResponseReceived(final HttpResponse response) {
             System.out.println("Response: " + response.getStatusLine());
             System.out.println("Header: " + response.toString());
             try {   
                 //if(response.getStatusLine().getStatusCode()==200)
                     fos = new FileOutputStream( "Response.html" );
             }catch(Exception e){
                 System.out.println("[onResponseReceived] Exception: " + e.getMessage());
             }
        }

        @Override
        protected void onCharReceived(final CharBuffer buf, final IOControl ioctrl) throws IOException {
            try
            {
                while (buf.hasRemaining()) 
                {
                    //System.out.print(buf.get());
                    fos.write(buf.get());
                }
            }catch(Exception e)
            {
                System.out.println("[onCharReceived] Exception: " + e.getMessage());
            }
        }

        @Override
        protected void onCleanup() {
            try
            {             
                if(fos!=null)
                    fos.close();
            }catch(Exception e){
                System.out.println("[onCleanup] Exception: " + e.getMessage());         
            }
             System.out.println("onCleanup()");
        }

        @Override
        protected Boolean buildResult() {
            return Boolean.TRUE;
        }

    }
}

错误：

URI Query: https://176.66.3.69:6443/download.aspx?Lang=EN&AuthToken=package
Aug 2, 2011 3:47:57 PM org.apache.http.impl.nio.client.NHttpClientProtocolHandler exception
SEVERE: I/O error: General SSLEngine problem
javax.net.ssl.SSLHandshakeException: General SSLEngine problem
    at com.sun.net.ssl.internal.ssl.Handshaker.checkThrown(Unknown Source)
    at com.sun.net.ssl.internal.ssl.SSLEngineImpl.checkTaskThrown(Unknown Source)
    at com.sun.net.ssl.internal.ssl.SSLEngineImpl.writeAppRecord(Unknown Source)
    at com.sun.net.ssl.internal.ssl.SSLEngineImpl.wrap(Unknown Source)
    at javax.net.ssl.SSLEngine.wrap(Unknown Source)
    at org.apache.http.impl.nio.reactor.SSLIOSession.doHandshake(SSLIOSession.java:154)
    at org.apache.http.impl.nio.reactor.SSLIOSession.isAppInputReady(SSLIOSession.java:276)
    at org.apache.http.impl.nio.client.InternalClientEventDispatch.inputReady(InternalClientEventDispatch.java:79)
    at org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:161)
    at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:335)
    at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:315)
    at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:275)
    at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:104)
    at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:542)
    at java.lang.Thread.run(Unknown Source)
Caused by: javax.net.ssl.SSLHandshakeException: General SSLEngine problem
    at com.sun.net.ssl.internal.ssl.Alerts.getSSLException(Unknown Source)
    at com.sun.net.ssl.internal.ssl.SSLEngineImpl.fatal(Unknown Source)
    at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Unknown Source)
    at com.sun.net.ssl.internal.ssl.Handshaker.fatalSE(Unknown Source)
    at com.sun.net.ssl.internal.ssl.ClientHandshaker.serverCertificate(Unknown Source)
    at com.sun.net.ssl.internal.ssl.ClientHandshaker.processMessage(Unknown Source)
    at com.sun.net.ssl.internal.ssl.Handshaker.processLoop(Unknown Source)
    at com.sun.net.ssl.internal.ssl.Handshaker$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.net.ssl.internal.ssl.Handshaker$DelegatedTask.run(Unknown Source)
    at org.apache.http.impl.nio.reactor.SSLIOSession.doHandshake(SSLIOSession.java:180)
    ... 9 more
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
    at sun.security.validator.PKIXValidator.doBuild(Unknown Source)
    at sun.security.validator.PKIXValidator.engineValidate(Unknown Source)
    at sun.security.validator.Validator.validate(Unknown Source)
    at com.sun.net.ssl.internal.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source)
    at com.sun.net.ssl.internal.ssl.JsseX509TrustManager.checkServerTrusted(Unknown Source)
    ... 16 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
    at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(Unknown Source)
    at java.security.cert.CertPathBuilder.build(Unknown Source)
    ... 21 more
onCleanup()

[DownloadFile] Exception: javax.net.ssl.SSLHandshakeException: General SSLEngine problem
Shutting down
Done