创建ServerSocket服务器

serverSocket = new ServerSocket(port);//首先创建一个服务端口
//等待客户端的连接请求
socket = serverSocket.accept();

等待Socket客户端连接

         //等待客户端的连接请求
         socket = serverSocket.accept();
         final String socketAddress = socket.getRemoteSocketAddress().toString();
         runOnUiThread(new Runnable() {
           @Override
           public void run() {
             Toast.makeText(ServerActivity.this, "成功建立与客户端的连接 : " + socketAddress, Toast.LENGTH_SHORT).show();
             Log.i("Lin", "成功建立与客户端的连接 : " + socketAddress);
           }
         });

接收Socket客户端信息

为了防止接收消息时，服务器inputStream.read()读取消息时产生阻塞，以换行符("\n")结束inputStream.read()

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               byte[] bytes = new byte[1];
               StringBuilder info = new StringBuilder();
               while (inputStream.read(bytes) != -1) {
                 String str = new String(bytes);
                 if (str.equals("\n")) {
                   break;
                 }
                 info.append(new String(bytes));
               }
               final String finalInfo = info.toString();
               Log.i("Lin", "text = " + finalInfo);
               runOnUiThread(new Runnable() {
                 @Override
                 public void run() {
                   mEtReceive.setText(mEtReceive.getText().toString() + socketAddress + " : " + finalInfo + "\n");
                 }
               });

接收Socket客户端文件

为了防止接收消息时，服务器inputStream.read()接受文件时产生阻塞，以文件MD5校验码进行校验，从而结束inputStream.read()

               byte[] remote = new byte[32];
               String md5 = "";
               if (inputStream.read(remote) != -1) {
                 md5 = nullOfString(new String(remote));
               }

               final String root = Environment.getExternalStorageDirectory().getPath();
               Log.i("Lin", root);
               byte[] inputByte = new byte[1024 * 1024];
               int len = 0;
               long fileSize = 0;

               DataInputStream dis = new DataInputStream(inputStream);
               // 文件名和长度
               String fileName = dis.readUTF();
               final long fileLength = dis.readLong();
               Log.i("Lin", "fileName = " + fileName);
               Log.i("Lin", "fileLength = " + fileLength);
               mPath = root + "/ECG/" + fileName;
               File file = new File(root + "/ECG/");
               if (!file.exists()) file.mkdir();
               file = new File(mPath);
               FileOutputStream fileOutputStream = new FileOutputStream(file);
               String fileMD5 = nullOfString(getFileMD5(new File(mPath)));
               while (!md5.equals(fileMD5) && (len = dis.read(inputByte, 0, inputByte.length)) > 0) {
                 fileSize += len;
                 fileOutputStream.write(inputByte, 0, len);
                 fileOutputStream.flush();
                 fileMD5 = nullOfString(getFileMD5(new File(mPath)));
                 Log.i("Lin", "md5 = " + md5 + " file = " + fileMD5);
                 Log.i("Lin", "fileLength = " + fileLength + " fileSize = " + fileSize + " " + (fileSize * 100 / fileLength) + "%")
                 ;
                 final long finalFileSize = fileSize;
                 runOnUiThread(new Runnable() {
                   @Override
                   public void run() {
                     mProgressDialog.setMessage((finalFileSize * 100 / fileLength) + "%");
                     mProgressDialog.show();
                   }
                 });
                 if (md5.equals(fileMD5)) {
                   fileOutputStream.close();
                   runOnUiThread(new Runnable() {
                     @Override
                     public void run() {
                       mProgressDialog.hide();
                     }
                   });
                 }
               }
               Log.i("Lin", "md52 = " + md5 + " file2 = " + getFileMD5(file));
               fileMD5 = nullOfString(getFileMD5(new File(mPath)));
               Log.i("Lin", "file = " + fileMD5);
               final String finalFileMD = fileMD5;
               final String finalMd = md5;
               runOnUiThread(new Runnable() {
                 @Override
                 public void run() {
                   mEtReceive.setText(mEtReceive.getText().toString() + "文件路径：" + mPath + "\n");
                   mEtReceive.setText(mEtReceive.getText().toString() + "file = " + finalFileMD + "\n");
                   mEtReceive.setText(mEtReceive.getText().toString() + "text = " + finalMd + "\n");
                 }
               });

客户端

创建Socket客户端

连接ServerSocket服务器

socket = new Socket();
socket.connect(new InetSocketAddress(ip, port));
//ip= 服务器ip
//port= 服务器端口

向ServerSocket服务器发送消息

             try {
               if (socket == null) return;
               OutputStream om = socket.getOutputStream();
               om.write(Constant.SERVER_TEXT.getBytes());
               om.write(returnServer.getBytes());
               om.write("\n".getBytes());//[10]
               om.flush();
             } catch (Exception e) {
               e.printStackTrace();
               Log.i("Lin", e.toString());
             }

为了防止发送消息时，服务器inputStream.read()读取消息时产生阻塞，客户端以换行符结束发送(om.write("\n".getBytes());)

向ServerSocket服务器发送文件

                   File file = new File(finalImagePath);
                   if (file.exists()) {
                     final String fileMD5 = nullOfString(getFileMD5(file));
                     OutputStream outputStream = socket.getOutputStream();
                     runOnUiThread(new Runnable() {
                       @Override
                       public void run() {
                         mEtReceive.setText(mEtReceive.getText().toString() + "file = " + fileMD5 + "\n");
                       }
                     });

                     FileInputStream fileInputStream = new FileInputStream(file);
                     outputStream.write(Constant.SERVER_FILE.getBytes());
                     outputStream.flush();
                     outputStream.write(fileMD5.getBytes());
                     outputStream.flush();
                     DataOutputStream dis = new DataOutputStream(outputStream);
                     // 文件名和长度
                     dis.writeUTF(file.getName());
                     dis.flush();
                     dis.writeLong(file.length());
                     dis.flush();
                     byte[] buffer = new byte[1024 * 1024];
                     int len = 0;
                     while ((len = fileInputStream.read(buffer, 0, buffer.length)) > 0) {
                       dis.write(buffer, 0, len);
                       dis.flush();
                     }
                     fileInputStream.close();
                     Log.i("Lin", "传输成功");
                   }

为了防止发送文件时，服务器inputStream.read()接受文件时产生阻塞，客户端先向服务器发送文件MD5校验码再发送文件，服务器对接收文件进行校验从而结束inputStream.read()阻塞。

Demo中发送格式

字符：SERVER_TEXT + 字符 + 换行符（\n）

文件：SERVER_FILE + 文件MD5校验码 + 文件

获取文件MD5

   private static String getFileMD5(File file) {
     if (!file.isFile()) {
       return null;
     }
     MessageDigest digest;
     FileInputStream in;
     try {
       byte[] buffer = new byte[1024];
       int len;
       digest = MessageDigest.getInstance("MD5");
       in = new FileInputStream(file);
       while ((len = in.read(buffer, 0, 1024)) != -1) {
         digest.update(buffer, 0, len);
       }
       in.close();
       BigInteger bigInt = new BigInteger(1, digest.digest());
       return bigInt.toString(16);
     } catch (Exception e) {
       e.printStackTrace();
       return null;
     }
   }

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