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

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() {
Sockets = null ;
try {
ServerSocketss = new ServerSocket(port);
while ( true ) {
// 选择进行传输的文件
StringfilePath = " D://lib.rar " ;
Filefi = new File(filePath);

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

// publicSocketaccept()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 " );
DataInputStreamdis = new DataInputStream( new BufferedInputStream(s.getInputStream()));
dis.readByte();

DataInputStreamfis = new DataInputStream( new BufferedInputStream( new FileInputStream(filePath)));
DataOutputStreamps = 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ThinkInJava4th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 (Exceptione) {
e.printStackTrace();
}
}

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

2.socket的Util辅助类

package sterning;

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

public class ClientSocket {
private Stringip;

private int port;

private Socketsocket = null ;

DataOutputStreamout = null ;

DataInputStreamgetMessageStream = null ;

public ClientSocket(Stringip, 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 (Exceptione) {
e.printStackTrace();
if (socket != null )
socket.close();
throw e;
} finally {
}
}

public void sendMessage(StringsendMessage) 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 (Exceptione) {
e.printStackTrace();
if (out != null )
out.close();
throw e;
} finally {
}
}

public DataInputStreamgetMessageStream() throws Exception {
try {
getMessageStream = new DataInputStream( new BufferedInputStream(socket.getInputStream()));
return getMessageStream;
} catch (Exceptione) {
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 (Exceptione) {

}
}
}

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 ClientSocketcs = null ;

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

private int port = 8821 ;

private StringsendMessage = " Windwos " ;

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

} catch (Exceptionex) {
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 (Exceptione) {
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 (Exceptione) {
System.out.print( " 发送消息失败! " + " /n " );
}
}

private void getMessage() {
if (cs == null )
return ;
DataInputStreaminputStream = null ;
try {
inputStream = cs.getMessageStream();
} catch (Exceptione) {
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。
StringsavePath = " E:// " ;
int bufferSize = 8192 ;
byte []buf = new byte [bufferSize];
int passedlen = 0 ;
long len = 0 ;

savePath += inputStream.readUTF();
DataOutputStreamfileOut = 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 (Exceptione) {
System.out.println( " 接收消息错误 " + " /n " );
return ;
}
}

public static void main(Stringarg[]) {
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.

Java基于Socket文件传输示例