connection timed out : connect

场景：Connection timed out: connect ！

Connection timed out: connect 在线等！！！！！！！
package com.zdvictory.wjj.common;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
/**
 * 
 * @author huoyutu
 *
 */
public class Tools {
private String sessionId;
// private Tools(){}  
// private static final Tools tool=new Tools();  
// public static Tools getInstance() {  
// return tool;  
// }  

public boolean makeHtml(String loginUrl, String username, String password, String url, String filePath, String chartset) {
HttpURLConnection huc = null;
BufferedReader br = null;
BufferedWriter bw = null;
try {
if(this.getSessionId()==null || "".equals(this.getSessionId())){
this.sendLoginRequest(loginUrl, username, password);
}
huc = (HttpURLConnection) new URL(url).openConnection();
huc.setRequestProperty("Cookie",this.getSessionId());
huc.connect();

InputStream stream = huc.getInputStream();
bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(filePath), chartset));
br = new BufferedReader(new InputStreamReader(stream, chartset));
String line;
while ((line = br.readLine()) != null) {
if (line.trim().length() > 0) {
bw.write(line);
bw.newLine();
}
}
} catch (Exception e) {
e.printStackTrace();
return false;
} finally {
try {
br.close();
bw.close();
huc.disconnect();
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
return true;
}

public void sendLoginRequest(String url,String username,String password) throws IOException {
URL loginUrl = new URL(url);
  HttpURLConnection connection = (HttpURLConnection) loginUrl.openConnection(); 
  // Output to the connection. Default is
  // false, set to true because post
  // method must write something to the
  // connection
  // 设置是否向connection输出，因为这个是post请求，参数要放在http正文内，因此需要设为true
  connection.setDoOutput(true);
  // Read from the connection. Default is true.
  connection.setDoInput(true);
  // Set the post method. Default is GET
  connection.setRequestMethod("POST");
  // Post cannot use caches
  // Post 请求不能使用缓存
connection.setUseCaches(false);
 
// This method takes effects to
// every instances of this class.
// URLConnection.setFollowRedirects是static函数，作用于所有的URLConnection对象。
// connection.setFollowRedirects(true);
 
// This methods only
// takes effacts to this
// instance.
// URLConnection.setInstanceFollowRedirects是成员函数，仅作用于当前函数
connection.setInstanceFollowRedirects(false);
 
// Set the content type to urlencoded,
// because we will write
// some URL-encoded content to the
// connection. Settings above must be set before connect!
// 配置本次连接的Content-type，配置为application/x-www-form-urlencoded的
// 意思是正文是urlencoded编码过的form参数，下面我们可以看到我们对正文内容使用URLEncoder.encode进行编码
//connection.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
// 连接，从postUrl.openConnection()至此的配置必须要在connect之前完成，
// 要注意的是connection.getOutputStream会隐含的进行connect。
connection.connect();
 
DataOutputStream out = new DataOutputStream(connection.getOutputStream());
 
// 要传的参数
String content = URLEncoder.encode("loginId", "UTF-8") +"="+ URLEncoder.encode(username, "UTF-8");
content += "&" + URLEncoder.encode("password", "UTF-8") +"="+ URLEncoder.encode(password, "UTF-8");
 
// DataOutputStream.writeBytes将字符串中的16位的unicode字符以8位的字符形式写道流里面
out.writeBytes(content);
 
// flush and close
out.flush();
out.close();
 
//Get Session ID  
if (connection != null) {
String key = "";
String session_str = "";
for (int i = 1; (key = connection.getHeaderFieldKey(i)) != null; i++) {
if (key.equalsIgnoreCase("set-cookie")) {
session_str = connection.getHeaderField(key);
session_str = session_str.substring(0, session_str.indexOf(";"));
 
this.setSessionId(session_str);
}
} 
}  
connection.disconnect();
  }

public String getSessionId() {
return sessionId;
}
public void setSessionId(String sessionId) {
this.sessionId = sessionId;
}
}

下面是错误信息
java.net.ConnectException: Connection timed out: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.Socket.connect(Socket.java:516)
at java.net.Socket.connect(Socket.java:466)
at sun.net.NetworkClient.doConnect(NetworkClient.java:157)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:365)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:477)
at sun.net.www.http.HttpClient.<init>(HttpClient.java:214)
at sun.net.www.http.HttpClient.New(HttpClient.java:287)
at sun.net.www.http.HttpClient.New(HttpClient.java:299)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:795)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:747)
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:672)
at com.zdvictory.wjj.common.Tools.sendLoginRequest(Tools.java:147)
at com.zdvictory.wjj.common.Tools.makeHtml(Tools.java:34)
at com.zdvictory.wjj.pricesend.action.PcServerObjectAction.sendMail(PcServerObjectAction.java:277)
java.lang.NullPointerException
at com.zdvictory.wjj.common.Tools.makeHtml(Tools.java:55)

------解决方案--------------------