javasocket文件上传

1. 基于java Socket实现文件传输

如果使用TCP套接字，关键是协议设计的问题，需要区别网络数据流中各部分的含义，如果使用UDP套接字，还是协议设计的问题，但是太有挑战性了，建议不要尝试。

2. Java socket上传文件，服务器的文件比上传的多了一行（最后一行）。不知道怎么处理（代码如下）

inti=0;
while((line=clientIn.readLine())!=null){
if(i++!=0)
bw.newLine();
bw.write(line);
bw.flush();
}

3. java使用socket文件上传

for(int size=0;size!=-1;size=fis.read(buf)){
output.write(buf,0,size);
output.flush();
}
for(int size=0;size!=-1;size=fis.read(buf))
在buf中读取字节;当buf没有内容了,返回的-1;在这个之前,一直在循环;
output.write(buf,0,size);
output.flush();
把buf中道0开始到size个字节的内容写入输出流缓冲中
并用 flush()确认发送到输出流中了;
我的意见是output.write(buf,0,size);
改为output.write(buf);
你接受数据部分代码怎么写的,是不是size等于一个大于1024的整数了而出错

4. 关于用JAVA的SOCKET传输文件

点对点传输文件
/*
import java.io.*;
import java.net.*;
import java.util.*;
*/
private HttpURLConnection connection;//存储连接
private int downsize = -1;//下载文件大小,初始值为-1
private int downed = 0;//文加已下载大小,初始值为0
private RandomAccessFile savefile;//记录下载信息存储文件
private URL fileurl;//记录要下载文件的地址
private DataInputStream fileStream;//记录下载的数据流
try{
/*开始创建下载的存储文件,并初始化值*/
File tempfileobject = new File("h:\\webwork-2.1.7.zip");
if(!tempfileobject.exists()){
/*文件不存在则建立*/
tempfileobject.createNewFile();
}
savefile = new RandomAccessFile(tempfileobject,"rw");

/*建立连接*/
fileurl = new URL("https://webwork.dev.java.net/files/documents/693/9723/webwork-2.1.7.zip");
connection = (HttpURLConnection)fileurl.openConnection();
connection.setRequestProperty("Range","byte="+this.downed+"-");

this.downsize = connection.getContentLength();
//System.out.println(connection.getContentLength());

new Thread(this).start();
}
catch(Exception e){
System.out.println(e.toString());
System.out.println("构建器错误");
System.exit(0);
}
public void run(){
/*开始下载文件,以下测试非断点续传,下载的文件存在问题*/
try{
System.out.println("begin!");
Date begintime = new Date();
begintime.setTime(new Date().getTime());
byte[] filebyte;
int onecelen;
//System.out.println(this.connection.getInputStream().getClass().getName());
this.fileStream = new DataInputStream(
new BufferedInputStream(
this.connection.getInputStream()));
System.out.println("size = " + this.downsize);
while(this.downsize != this.downed){
if(this.downsize - this.downed > 262144){//设置为最大256KB的缓存
filebyte = new byte[262144];
onecelen = 262144;
}
else{
filebyte = new byte[this.downsize - this.downed];
onecelen = this.downsize - this.downed;
}
onecelen = this.fileStream.read(filebyte,0,onecelen);
this.savefile.write(filebyte,0,onecelen);
this.downed += onecelen;
System.out.println(this.downed);
}
this.savefile.close();
System.out.println("end!");
System.out.println(begintime.getTime());
System.out.println(new Date().getTime());
System.out.println(begintime.getTime() - new Date().getTime());
}
catch(Exception e){
System.out.println(e.toString());
System.out.println("run()方法有问题!");
}
}

/***
//FileClient.java
import java.io.*;
import java.net.*;
public class FileClient {
public static void main(String[] args) throws Exception {

//使用本地文件系统接受网络数据并存为新文件

File file = new File("d:\\fmd.doc");

file.createNewFile();

RandomAccessFile raf = new RandomAccessFile(file, "rw");

// 通过Socket连接文件服务器

Socket server = new Socket(InetAddress.getLocalHost(), 3318);
//创建网络接受流接受服务器文件数据
InputStream netIn = server.getInputStream();
InputStream in = new DataInputStream(new BufferedInputStream(netIn));
//创建缓冲区缓冲网络数据

byte[] buf = new byte[2048];

int num = in.read(buf);

while (num != (-1)) {//是否读完所有数据

raf.write(buf, 0, num);//将数据写往文件

raf.skipBytes(num);//顺序写文件字节

num = in.read(buf);//继续从网络中读取文件

}
in.close();
raf.close();
}
}

//FileServer.java
import java.io.*;
import java.util.*;
import java.net.*;
public class FileServer {
public static void main(String[] args) throws Exception {

//创建文件流用来读取文件中的数据

File file = new File("d:\\系统特点.doc");

FileInputStream fos = new FileInputStream(file);

//创建网络服务器接受客户请求

ServerSocket ss = new ServerSocket(8801);

Socket client = ss.accept();

//创建网络输出流并提供数据包装器

OutputStream netOut = client.getOutputStream();

OutputStream doc = new DataOutputStream(
new BufferedOutputStream(netOut));

//创建文件读取缓冲区

byte[] buf = new byte[2048];

int num = fos.read(buf);
while (num != (-1)) {//是否读完文件
doc.write(buf, 0, num);//把文件数据写出网络缓冲区
doc.flush();//刷新缓冲区把数据写往客户端
num = fos.read(buf);//继续从文件中读取数据
}
fos.close();
doc.close();
}
}
*/

5. 怎么用java的socket进行文件传输谁能给个简单的例子，包括发送端和接收端。

java中的网络信息传输方式是基于TCP协议或者UD协议P的,socket是基于TCP协议的

例子1
（1）客户端程序：
import java.io.*;
import java.net.*;
public class Client
{ public static void main(String args[])
{ String s=null;
Socket mysocket;
DataInputStream in=null;
DataOutputStream out=null;
try{
mysocket=new Socket("localhost",4331);
in=new DataInputStream(mysocket.getInputStream());
out=new DataOutputStream(mysocket.getOutputStream());
out.writeUTF("你好！");//通过 out向"线路"写入信息。
while(true)
{
s=in.readUTF();//通过使用in读取服务器放入"线路"里的信息。堵塞状态，
//除非读取到信息。
out.writeUTF(":"+Math.random());
System.out.println("客户收到:"+s);
Thread.sleep(500);
}
}
catch(IOException e)
{ System.out.println("无法连接");
}
catch(InterruptedException e){}
}
}
（2）服务器端程序：
import java.io.*;import java.net.*;
public class Server
{ public static void main(String args[])
{ ServerSocket server=null;
Socket you=null;String s=null;
DataOutputStream out=null;DataInputStream in=null;
try{ server=new ServerSocket(4331);}
catch(IOException e1){System.out.println("ERRO:"+e1);}
try{ you=server.accept();
in=new DataInputStream(you.getInputStream());
out=new DataOutputStream(you.getOutputStream());
while(true)
{
s=in.readUTF();// 通过使用in读取客户放入"线路"里的信息。堵塞状态，
//除非读取到信息。

out.writeUTF("你好:我是服务器");//通过 out向"线路"写入信息.
out.writeUTF("你说的数是:"+s);
System.out.println("服务器收到:"+s);
Thread.sleep(500);
}
}
catch(IOException e)
{ System.out.println(""+e);
}
catch(InterruptedException e){}
}
}

例子(2)
(1) 客户端
import java.net.*;import java.io.*;
import java.awt.*;import java.awt.event.*;
import java.applet.*;
public class Computer_client extends Applet implements Runnable,ActionListener
{ Button 计算;TextField 输入三边长度文本框,计算结果文本框;
Socket socket=null;
DataInputStream in=null; DataOutputStream out=null;
Thread thread;
public void init()
{ setLayout(new GridLayout(2,2));
Panel p1=new Panel(),p2=new Panel();
计算=new Button(" 计算");
输入三边长度文本框=new TextField(12);计算结果文本框=new TextField(12);
p1.add(new Label("输入三角形三边的长度,用逗号或空格分隔:"));
p1.add( 输入三边长度文本框);
p2.add(new Label("计算结果："));p2.add(计算结果文本框);p2.add(计算);
计算.addActionListener(this);
add(p1);add(p2);
}
public void start()
{ try
{ //和小程序所驻留的服务器建立套接字连接：
socket = new Socket(this.getCodeBase().getHost(), 4331);
in =new DataInputStream(socket.getInputStream());
out = new DataOutputStream(socket.getOutputStream());
}
catch (IOException e){}
if(thread == null)
{ thread = new Thread(this);
thread.start();
}
}
public void run()
{ String s=null;
while(true)
{ try{ s=in.readUTF();//堵塞状态，除非读取到信息。

计算结果文本框.setText(s);
}
catch(IOException e)
{ 计算结果文本框.setText("与服务器已断开");
break;
}
}
}
public void actionPerformed(ActionEvent e)
{ if(e.getSource()==计算)
{ String s=输入三边长度文本框.getText();
if(s!=null)
{ try { out.writeUTF(s);
}
catch(IOException e1){}
}
}
}
}

(2) 服务器端
import java.io.*;import java.net.*;
import java.util.*;import java.sql.*;
public class Computer_server
{ public static void main(String args[])
{ ServerSocket server=null;Server_thread thread;
Socket you=null;
while(true)
{ try{ server=new ServerSocket(4331);
}
catch(IOException e1)
{ System.out.println("正在监听"); //ServerSocket对象不能重复创建。
}
try{ you=server.accept();
System.out.println("客户的地址:"+you.getInetAddress());
}
catch (IOException e)
{ System.out.println("正在等待客户");
}
if(you!=null)
{ new Server_thread(you).start(); //为每个客户启动一个专门的线程。
}
else
{ continue;
}
}
}
}
class Server_thread extends Thread
{ Socket socket;Connection Con=null;Statement Stmt=null;
DataOutputStream out=null;DataInputStream in=null;int n=0;
String s=null;
Server_thread(Socket t)
{ socket=t;
try { in=new DataInputStream(socket.getInputStream());
out=new DataOutputStream(socket.getOutputStream());
}
catch (IOException e)
{}
}
public void run()
{ while(true)
{ double a[]=new double[3] ;int i=0;
try{ s=in.readUTF();堵塞状态，除非读取到信息。

StringTokenizer fenxi=new StringTokenizer(s," ,");
while(fenxi.hasMoreTokens())
{ String temp=fenxi.nextToken();
try{ a[i]=Double.valueOf(temp).doubleValue();i++;
}
catch(NumberFormatException e)
{ out.writeUTF("请输入数字字符");
}
}
double p=(a[0]+a[1]+a[2])/2.0;
out.writeUTF(" "+Math.sqrt(p*(p-a[0])*(p-a[1])*(p-a[2])));
sleep(2);
}
catch(InterruptedException e){}
catch (IOException e)
{ System.out.println("客户离开");
break;
}
}
}
}

这些例子都是Java2实用教程上的.

6. 用java socket实现一个服务器对多个客户端的文件传输

通过socket可以用如下方式进行。
1.启动服务端代码。
2.启动客户端自动连接服务端。
3.服务端上传文件，保存文件和路径。
4.将路径发送给连接服务端的客户端。

7. 利用java socket实现文件传输

1.服务器端

package sterning;

import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class ServerTest {
int port = 8821;

void start() {
Socket s = null;
try {
ServerSocket ss = new ServerSocket(port);
while (true) {
// 选择进行传输的文件
String filePath = "D:\\lib.rar";
File fi = new File(filePath);

System.out.println("文件长度:" + (int) fi.length());

// public Socket accept() throws
// IOException侦听并接受到此套接字的连接。此方法在进行连接之前一直阻塞。

s = ss.accept();
System.out.println("建立socket链接");
DataInputStream dis = new DataInputStream(new BufferedInputStream(s.getInputStream()));
dis.readByte();

DataInputStream fis = new DataInputStream(new BufferedInputStream(new FileInputStream(filePath)));
DataOutputStream ps = new DataOutputStream(s.getOutputStream());
//将文件名及长度传给客户端。这里要真正适用所有平台，例如中文名的处理，还需要加工，具体可以参见Think In Java 4th里有现成的代码。
ps.writeUTF(fi.getName());
ps.flush();
ps.writeLong((long) fi.length());
ps.flush();

int bufferSize = 8192;
byte[] buf = new byte[bufferSize];

while (true) {
int read = 0;
if (fis != null) {
read = fis.read(buf);
}

if (read == -1) {
break;
}
ps.write(buf, 0, read);
}
ps.flush();
// 注意关闭socket链接哦，不然客户端会等待server的数据过来，
// 直到socket超时，导致数据不完整。
fis.close();
s.close();
System.out.println("文件传输完成");
}

} catch (Exception e) {
e.printStackTrace();
}
}

public static void main(String arg[]) {
new ServerTest().start();
}
}

2.socket的Util辅助类

package sterning;

import java.net.*;
import java.io.*;

public class ClientSocket {
private String ip;

private int port;

private Socket socket = null;

DataOutputStream out = null;

DataInputStream getMessageStream = null;

public ClientSocket(String ip, int port) {
this.ip = ip;
this.port = port;
}

/** *//**
* 创建socket连接
*
* @throws Exception
* exception
*/
public void CreateConnection() throws Exception {
try {
socket = new Socket(ip, port);
} catch (Exception e) {
e.printStackTrace();
if (socket != null)
socket.close();
throw e;
} finally {
}
}

public void sendMessage(String sendMessage) throws Exception {
try {
out = new DataOutputStream(socket.getOutputStream());
if (sendMessage.equals("Windows")) {
out.writeByte(0x1);
out.flush();
return;
}
if (sendMessage.equals("Unix")) {
out.writeByte(0x2);
out.flush();
return;
}
if (sendMessage.equals("Linux")) {
out.writeByte(0x3);
out.flush();
} else {
out.writeUTF(sendMessage);
out.flush();
}
} catch (Exception e) {
e.printStackTrace();
if (out != null)
out.close();
throw e;
} finally {
}
}

public DataInputStream getMessageStream() throws Exception {
try {
getMessageStream = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
return getMessageStream;
} catch (Exception e) {
e.printStackTrace();
if (getMessageStream != null)
getMessageStream.close();
throw e;
} finally {
}
}

public void shutDownConnection() {
try {
if (out != null)
out.close();
if (getMessageStream != null)
getMessageStream.close();
if (socket != null)
socket.close();
} catch (Exception e) {

}
}
}

3.客户端

package sterning;

import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileOutputStream;

public class ClientTest {
private ClientSocket cs = null;

private String ip = "localhost";// 设置成服务器IP

private int port = 8821;

private String sendMessage = "Windwos";

public ClientTest() {
try {
if (createConnection()) {
sendMessage();
getMessage();
}

} catch (Exception ex) {
ex.printStackTrace();
}
}

private boolean createConnection() {
cs = new ClientSocket(ip, port);
try {
cs.CreateConnection();
System.out.print("连接服务器成功!" + "\n");
return true;
} catch (Exception e) {
System.out.print("连接服务器失败!" + "\n");
return false;
}

}

private void sendMessage() {
if (cs == null)
return;
try {
cs.sendMessage(sendMessage);
} catch (Exception e) {
System.out.print("发送消息失败!" + "\n");
}
}

private void getMessage() {
if (cs == null)
return;
DataInputStream inputStream = null;
try {
inputStream = cs.getMessageStream();
} catch (Exception e) {
System.out.print("接收消息缓存错误\n");
return;
}

try {
//本地保存路径，文件名会自动从服务器端继承而来。
String savePath = "E:\\";
int bufferSize = 8192;
byte[] buf = new byte[bufferSize];
int passedlen = 0;
long len=0;

savePath += inputStream.readUTF();
DataOutputStream fileOut = new DataOutputStream(new BufferedOutputStream(new BufferedOutputStream(new FileOutputStream(savePath))));
len = inputStream.readLong();

System.out.println("文件的长度为:" + len + "\n");
System.out.println("开始接收文件!" + "\n");

while (true) {
int read = 0;
if (inputStream != null) {
read = inputStream.read(buf);
}
passedlen += read;
if (read == -1) {
break;
}
//下面进度条本为图形界面的prograssBar做的，这里如果是打文件，可能会重复打印出一些相同的百分比
System.out.println("文件接收了" + (passedlen * 100/ len) + "%\n");
fileOut.write(buf, 0, read);
}
System.out.println("接收完成，文件存为" + savePath + "\n");

fileOut.close();
} catch (Exception e) {
System.out.println("接收消息错误" + "\n");
return;
}
}

public static void main(String arg[]) {
new ClientTest();
}
}