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()



{



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();



}



}

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.