TCP使用（二）多用户发送文件和登录

 

服务器端接收多个客户端同时发送的文件

血的教训：

在服务器端未添加while (true) {Socket s = ss.accept();new Thread(new MyThread(s)).start();} 

 导致程序运行的次，服务器端就关闭

 

 

客户端：

public static void main(String[] args)throws Exception {File file = new File("c:\\QQ.jpg");if(!(file.exists() && file.isFile())){return ;}if(!file.getName().endsWith(".jpg")){return ;}if(file.length()>1024*1024*5){return ;}Socket s = new Socket("192.168.1.117",10009);FileInputStream fis = new FileInputStream(file);OutputStream out = s.getOutputStream();byte[] buf = new byte[1024];int len = 0;while((len=fis.read(buf))!=-1){out.write(buf,0,len);}s.shutdownOutput();InputStream in = s.getInputStream();byte[] bufIn = new byte[1024];int num = in.read(bufIn);System.out.println(new String(bufIn,0,num));fis.close();s.close();}

服务器端:

public static void main(String[] args) throws IOException {ServerSocket ss = new ServerSocket(10009);while (true) {Socket s = ss.accept();new Thread(new MyThread(s)).start();}}

public class MyThread implements Runnable {Socket s;public MyThread(Socket s) {super();this.s = s;}public void run() {int count = 1;String ip = s.getInetAddress().getHostAddress();try {System.out.println(ip + "....connected");InputStream in = s.getInputStream();File dir = new File("d:\\pic");dir.mkdirs();File file = new File(dir, ip + "(" + (count) + ")" + ".jpg");while (file.exists())file = new File(dir, ip + "(" + (count++) + ")" + ".jpg");FileOutputStream fos = new FileOutputStream(file);byte[] buf = new byte[1024];int len = 0;while ((len = in.read(buf)) != -1) {fos.write(buf, 0, len);}OutputStream out = s.getOutputStream();out.write("上传成功".getBytes());fos.close();s.close();} catch (Exception e) {throw new RuntimeException(ip + "上传失败");}}}

 

TCP验证多用户登录：

示例：

说明：服务器端同时验证多个用户登录，限制登录三次，客户端控制台输入用户名进行登录

 血的教训：

在使用printWriter的时候 new PrintWriter(os,true);第二个值为true的时候，使用方法println()会自动刷入数据。

如果使用writer()方法还需要flush()手动刷入，并且该方法无法自动加入换行符

 客户端：

public class Demo25 {public static void main(String[] args) throws IOException {try {Socket s = new Socket("192.168.1.117", 10009);BufferedReader bwIn = new BufferedReader(new InputStreamReader(s.getInputStream()));BufferedReader brSys = new BufferedReader(new InputStreamReader(System.in));BufferedWriter bwOut = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));for (int i = 0; i < 3; i++) {String name = brSys.readLine();System.out.print(name);if (name == null) {System.out.println("用户名不能为空");}bwOut.write(name);bwOut.newLine();bwOut.flush();String request = bwIn.readLine();System.out.println(request);}System.out.println("登录超过三次，自动退出");// bwOut.close();s.close();} catch (IOException e) {e.printStackTrace();}}}

服务器端：

public class Demo26 {public static void main(String[] args) {try {ServerSocket ss = new ServerSocket(10009);while (true) {Socket s = ss.accept();new Thread(new Demo26Thread(s)).start();}} catch (IOException e) {e.printStackTrace();}}}

public class Demo26Thread implements Runnable {public Socket s;public Demo26Thread(Socket s) {super();this.s = s;}public void run() {try {BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));PrintWriter pw = new PrintWriter(s.getOutputStream(),true);boolean isLogin = false;for (int i = 0; i < 3; i++) {String name = br.readLine();System.out.println("Server:" + name);String loginName = null;BufferedReader brFile = new BufferedReader(new InputStreamReader(new FileInputStream("D:\\login.txt")));while ((loginName = brFile.readLine()) != null) {isLogin = name.equals(loginName);if (isLogin) {break;}}if (isLogin) {System.out.println(name + "isLogin");//pw.println("Login Success");pw.write("Login Success\r\n");break;} else {pw.write("Login defeated\r\n");//pw.println("Login defeated");}pw.flush();}pw.close();s.close();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}// TODO Auto-generated method stub}}