Java基于Socket文件传输示例

Java基于Socket文件传输示例

最近需要进行网络传输大文件，于是对基于socket的文件传输作了一个初步的了解。在一位网友提供的程序基础上，俺进行了一些加工，采用了缓冲输入/输出流来包装输出流，再采用数据输入/输出输出流进行包装，加快传输的速度。废话少说，先来看服务器端的程序。

1.服务器端

packagesterning;

importjava.io.BufferedInputStream;
importjava.io.DataInputStream;
importjava.io.DataOutputStream;
importjava.io.File;
importjava.io.FileInputStream;
importjava.net.ServerSocket;
importjava.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ThinkIn 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 = newbyte[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

packagesterning;

importjava.net.*;
importjava.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;
}


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

packagesterning;

importjava.io.BufferedOutputStream;
importjava.io.DataInputStream;
importjava.io.DataOutputStream;
importjava.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 = newbyte[bufferSize];
int passedlen = 0;
long len=0;

savePath += inputStream.readUTF();
DataOutputStream fileOut = newDataOutputStream(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();
}
}

这就实现了从服务器端向客户端发送文件的过程,当然,反过来,也一样.稍有不同.代码中对跨平台的细节没有实现,有时间或兴趣的朋友可以提供一下.