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;
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
packagesterning;
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();