public class FileDownloader implements Runnable
{
private static File file//要下载的文件
private static String url//文件所在URL
private static File storagePath//保存路径
public static void initialize(File file, String url, File storagePath)//初始化静态字段，初始化的代码不用我写吧
}
然后，指明同步块，目的是让各个线程共享一个文件资源，那样它们可以知道同一个文件的下载状况(即获取其他线程下载文件到哪个位置，以防重复下载)
public synchronized void fileDownload()//此方法用于下载文件，一般的Java程序员都会写，实在不会我可以帮你补上
或者
public void fileDownload(){
synchronized(file){
synchronized(url){
synchronized(storagePath){
}}}}//给每个字段加上同步块
run()方法的实现就以自己的喜好去写吧，只要里面调用了fileDownload()方法就行。
public void run(){
…
fileDownload()//下载文件
…
}
然后，在主类的main方法中创建一个多线程数组:
Runnable[] fds=new FileDownloader[线程数量]//fds为file_downloaders缩写
Thread[] threads=new Thread[线程数量]
最后使用循环把所有的线程逐一启动。
for(int i=0i<线程数量i++){
threads[i]=new Thread(fds[i])
threads[i].start()
}
单纯的就上面个这个代码来说是没有问题的。你先打印出http.getResponseCode()的值是多少。到API中去看对应的原因是什么。状态码打印出来了去HttpURLConnection类下面找对应的错误描述。找到原因了就自然解决了，你给的代码太少了。也只能给你分析到这里了。程序分Server和Client服务器端打开侦听的端口，一有客户端连接就创建两个新的线程来负责这个连接
一个负责客户端发送的信息(ClientMsgCollectThread 类)，
另一个负责通过该Socket发送数据（ServerMsgSendThread ）
Server.java代码如下:
/*
* 创建日期 2009-3-7
*
* TODO 要更改此生成的文件的模板，请转至
* 窗口 － 首选项 － Java － 代码样式 － 代码模板
*/
package faue.MutiUser
import java.io.BufferedReader
import java.io.IOException
import java.io.InputStreamReader
import java.io.PrintWriter
import java.net.ServerSocket
import java.net.Socket
/**
* 服务器端
*
* @author Faue
*/
public class Server extends ServerSocket {
private static final int SERVER_PORT = 10000
/**
* 构造方法，用于实现连接的监听
*
* @throws IOException
*/
public Server() throws IOException {
super(SERVER_PORT)
try {
while (true) {
Socket socket = super.accept()
new Thread(new ClientMsgCollectThread(socket), "getAndShow"
+ socket.getPort()).start()
new Thread(new ServerMsgSendThread(socket), "send"
+ socket.getPort()).start()
}
} catch (IOException e) {
e.printStackTrace()
}
}
public static void main(String[] args) throws IOException {
new Server()
}
/**
* 该类用于创建接收客户端发来的信息并显示的线程
*
* @author Faue
* @version 1.0.0
*/
class ClientMsgCollectThread implements Runnable {
private Socket client
private BufferedReader in
private StringBuffer inputStringBuffer = new StringBuffer("Hello")
/**
* 得到Socket的输入流
*
* @param s
* @throws IOException
*/
public ClientMsgCollectThread(Socket s) throws IOException {
client = s
in = new BufferedReader(new InputStreamReader(client
.getInputStream(), "GBK"))
}
public void run() {
try {
while (!client.isClosed()) {
inputStringBuffer.delete(0, inputStringBuffer.length())
inputStringBuffer.append(in.readLine())
System.out.println(getMsg(inputStringBuffer.toString()))
}
} catch (IOException e) {
//e.printStackTrace()
System.out.println(client.toString() + " is closed!")
}
}
/**
* 构造显示的字符串
*
* @param line
* @return
*/
private String getMsg(String line) {
return client.toString() + " says:" + line
}
}
/**
* 该类用于创建发送数据的线程
*
* @author Faue
* @version 1.0.0
*/
class ServerMsgSendThread implements Runnable {
private Socket client
private PrintWriter out
private BufferedReader keyboardInput
private StringBuffer outputStringBuffer = new StringBuffer("Hello")
/**
* 得到键盘的输入流
*
* @param s
* @throws IOException
*/
public ServerMsgSendThread(Socket s) throws IOException {
client = s
out = new PrintWriter(client.getOutputStream(), true)
keyboardInput = new BufferedReader(new InputStreamReader(System.in))
}
public void run() {
try {
while (!client.isClosed()) {
outputStringBuffer.delete(0, outputStringBuffer.length())
outputStringBuffer.append(keyboardInput.readLine())
out.println(outputStringBuffer.toString())
}
} catch (IOException e) {
//e.printStackTrace()
System.out.println(client.toString() + " is closed!")
}
}
}
}
客户端：
实现基于IP地址的连接，连接后也创建两个线程来实现信息的发送和接收
/*
* 创建日期 2009-3-7
*
*/
package faue.MutiUser
import java.io.BufferedReader
import java.io.IOException
import java.io.InputStreamReader
import java.io.PrintWriter
import java.net.Socket
/**
* 客户端
*
* @author Faue
*/
public class Client {
private Socket mySocket
/**
* 创建线程的构造方法
*
* @param IP
* @throws IOException
*/
public Client(String IP) throws IOException {
try {
mySocket = new Socket(IP, 10000)
new Thread(new ServerMsgCollectThread(mySocket), "getAndShow"
+ mySocket.getPort()).start()
new Thread(new ClientMsgSendThread(mySocket), "send"
+ mySocket.getPort()).start()
} catch (IOException e) {
//e.printStackTrace()
System.out.println("Server.IP:" + IP
+ " port:10000 can not be Connected")
}
}
public static void main(String[] args) throws IOException {
try {
new Client(args[0])
} catch (Exception e) {
System.out.println("输入的IP地址错误")
}
}
/**
* 该类用于创建接收服务端发来的信息并显示的线程
*
* @author Faue
* @version 1.0.0
*/
class ServerMsgCollectThread implements Runnable {
private Socket client
private BufferedReader in
private StringBuffer inputStringBuffer = new StringBuffer("Hello")
/**
* 得到Socket的输入流
*
* @param s
* @throws IOException
*/
public ServerMsgCollectThread(Socket s) throws IOException {
client = s
in = new BufferedReader(new InputStreamReader(client
.getInputStream(), "GBK"))
}
public void run() {
try {
while (!client.isClosed()) {
inputStringBuffer.delete(0, inputStringBuffer.length())
inputStringBuffer.append(in.readLine())
System.out.println(getMsg(inputStringBuffer.toString()))
}
} catch (IOException e) {
//e.printStackTrace()
System.out.println(client.toString() + " is closed!")
System.exit(0)
}
}
/**
* 构造输入字符串
*
* @param line
* @return
*/
private String getMsg(String line) {
return client.toString() + " says:" + line
}
}
/**
* 该类用于创建发送数据的线程
*
* @author Faue
* @version 1.0.0
*/
class ClientMsgSendThread implements Runnable {
private Socket client
private PrintWriter out
private BufferedReader keyboardInput
private StringBuffer outputStringBuffer = new StringBuffer("Hello")
/**
* 得到键盘的输入流
*
* @param s
* @throws IOException
*/
public ClientMsgSendThread(Socket s) throws IOException {
client = s
out = new PrintWriter(client.getOutputStream(), true)
keyboardInput = new BufferedReader(new InputStreamReader(System.in))
}
public void run() {
try {
while (!client.isClosed()) {
outputStringBuffer.delete(0, outputStringBuffer.length())
outputStringBuffer.append(keyboardInput.readLine())
out.println(outputStringBuffer.toString())
}
out.println("--- See you, bye! ---")
} catch (IOException e) {
//e.printStackTrace()
System.out.println(client.toString() + " is closed!")
System.exit(0)
}
}
}
}
如果对您有帮助，请记得采纳为满意答案，谢谢！祝您生活愉快！
vaela
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