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(); }}

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) {}}}

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ipprivate 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(); }}