前一段时间刚做了个java程序和网络上多台机器的c程序通讯的项目，遵循的是TCP/IP协议，用到了java的Socket编程。网络通讯是java的强项，用TCP/IP协议可以方便的和网络上的其他程序互通消息。 先来介绍下网络协议： TCP/IP Transmission Control Protocol 传输控制协议 Internet Protocol 互联网协议 UDP User Datagram Protocol 用户数据协议 连接协议： 分为： 面向连接协议: Connection Oriented Protocol 非连接协议: Connectionless Protocol 1).面向连接协议是指两台电脑在传输数据前，先会建立一个专属的连接。就如电信局的交换机会为打电话双方提供专属连接一样。 Internet上的面向连接协议就是TCP/IP 特点：确认回应；分组序号；流量控制。 TCP/IP属于可靠性传输，适合不容许有传输错误的网络程序设计使用 2).非连接协议：无专属连接，无分组，容错，距离短，可同时对多台电脑进行数据传输 Internet上的非连接协议就是UDP TCP在网络通信上有极强的生命力，例如远程连接（Telnet）和文件传输（FTP）都需要不定长度的数据被可靠地传输。相比之下UDP操作简单，而且仅需要较少的监护，因此通常用于局域网高可靠性的分散系统中client/server应用程序。 Socket 是程序与网络间的一种接口，大部分网络应用程序都是点对点的，所谓点就是服务器端和客户端所执行的程序。Socket是用来接收和传送分组的一个端点。 java的Socket编程要用到java.net包，最常用的是net包下的6个类：InetAddress(互联网协议 (IP) 地址)类，Socket(套接字)类，ServerSocket(套接字服务器)类，DatagramSocket(发送和接收数据报包的套接字)类，DatagramPacket(数据报包)类，MulticastSocket(多播数据报套接字类用于发送和接收 IP 多播包)类，其中InetAddress、Socket、ServerSocket类是属于TCP面向连接协议，DatagramSocket、DatagramPacket和MulticastSocket类则属于UDP非连接协议的传送类。 本项目因为使用TCP/IP协议，主要用到Socket和ServerSocket类 项目代码如下
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package com.sse.monitor.serv; import java.io.DataInputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.BufferedOutputStream; import java.net.Socket; import java.net.UnknownHostException; import java.util.ArrayList; import com.sse.monitor.bean.Message; import com.sse.monitor.bean.MessageHead; import com.sse.monitor.bean.ResponseMessage; import com.sse.monitor.form.ListenerInvoke; import com.sse.monitor.form.MainForm; import com.sse.monitor.util.SwingUtils; /** * Socket套接字工厂，对外接口是静态方法 SocketFactory.request(String, String, String, int) * Copyright: Copyright (c) 2008 * Company: conserv * @author cuishen * @version 1.3 */public class SocketFactory { private Socket socket = null; private String targetIpAddress = null; private int targetPort = 0; private static SocketFactory sf = new SocketFactory(); public SocketFactory() { } /** * 建立一条TCP/IP连接 * @param targetIpAddress String 目标ip地址 * @param targetPort String 目标端口 * @throws IOException */private void connect(String targetIpAddress, int targetPort) throws IOException { setTargetIpAddress(targetIpAddress); setTargetPort(targetPort); if(socket == null) socket = new Socket(targetIpAddress, targetPort); } /** * 这是对外接口。发送命令，接收反馈和接收message放两个线程， * 发送命令并接收反馈是短连接，所以每次执行成功后，将销毁socket并终止线程， * 接收message是长连接，所以可能会new出n个线程，建议对接收message的线程做缓存 * @param commandType String 命令类型 * @param commandContent String 命令内容 * @param targetIP String 目标ip * @param targetPort int 目标端口 */public static void request(String commandType, String commandContent, String targetIP, int targetPort) { if (commandType.equalsIgnoreCase(MessageFactory.SCAN_COMMAND)) { sf.new GetMessageSocketThread(commandType, commandContent, targetIP, targetPort); } else { sf.new RequestSocketThread(commandType, commandContent, targetIP, targetPort); } } /** * 发送请求 * @param commandType String 命令类型 * @param commandContent String 命令内容 * @param targetIp String 目标ip */private void sendRequest(String commandType, String commandContent, String targetIp) { OutputStream os = null; BufferedOutputStream bs = null; try { os = socket.getOutputStream(); bs = new BufferedOutputStream(os); char[] message = MessageFactory.makeRequestMessage(targetIp, commandType, commandContent, MessageFactory.COMMAND_TRADE_CODE, MessageFactory.RIGHT_COMMAND, MessageFactory.MESSAGE_END_FLAG); for (int i = 0; i < message.length; i++) bs.write(new String(message).getBytes(), i, 1); bs.flush(); SwingUtils.appendLog(MainForm.jTextArea, "发送请求：'" + commandType + "' '" + commandContent + "' '" + targetIp + "'", ReadConfig.commandStateShowLineCount); } catch (IOException e) { SwingUtils.appendLog(MainForm.jTextArea, "Error!!! 发送请求：'" + commandType + "' '" + commandContent + "' '" + targetIp + "'失败！！ " + e.getMessage(), ReadConfig.commandStateShowLineCount); e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } finally { } } /** * 获得反馈 * * @return 如果成功获得反馈，则返回true；否则返回false */private boolean getResponse() { InputStream is = null; DataInputStream di = null; boolean returnFlag = false; try { is = socket.getInputStream(); di = new DataInputStream(is); byte[] temp = new byte[1]; int flag = 0; ArrayList tempByteList = new ArrayList(); int i = 0; while (flag != -1) { i++; flag = di.read(temp = new byte[1]); if (flag != -1) tempByteList.add(temp); if (i == 38) break; } if (i == 1) { SwingUtils.Error("未收到response!!!"); return false; } MessageHead messageHead = MessageFactory.readHead(tempByteList); SwingUtils.appendLog(MainForm.jTextArea, "收到 response", ReadConfig.commandStateShowLineCount); tempByteList = new ArrayList(); i = 0; while (flag != -1) { i++; flag = di.read(temp = new byte[1]); if (flag != -1) tempByteList.add(temp); if (i == 26) break; } byte[] length = new byte[4]; di.read(length); int len = Integer.parseInt(new String(length, MessageFactory.DEFAULT_CHAR_SET).trim()); flag = 0; for (int j = 0; j < (len + 37); j++) { flag = di.read(temp = new byte[1]); if (flag == -1) break; tempByteList.add(temp); } ResponseMessage rm = MessageFactory.readResponseMessage(tempByteList, len); if (messageHead.getErrorCode().equals(MessageFactory.SUCCESS)) returnFlag = true; else SwingUtils.Error("errorCode: " + messageHead.getErrorCode() + "; content: " + rm.getCommandContent()); } catch (IOException e) { e.printStackTrace(); } finally { } return returnFlag; } /** * 分发消息的方法,将消息按进程名发送到对应的消息缓存 * * 消息缓存ListenerInvoke.messageMap，key = machineName + * '|' + programName + '|' + processId, value = messageList * 存放messageMap里面的键名的List -- ListenerInvoke.messageMapKeyList * 进程状态缓存ListenerInvoke.processStateMap, key = machineName + '|' + * programName + '|' + processId, value = String * * @param message Message */private void distributeMess(Message message) { String machineName = message.getMachineName(); String programName = message.getProgramName(); String processId = message.getProcessId(); String content = message.getContent(); String key = machineName + '|' + programName + '|' + processId; key = key.trim(); ArrayList messageList = null; if (ListenerInvoke.messageMap.get(key) == null) { synchronized (ListenerInvoke.messageMap) { if (ListenerInvoke.messageMap.get(key) == null) { messageList = new ArrayList(); messageList.add(content); ListenerInvoke.messageMap.put(key, messageList); } } } else { messageList = (ArrayList) ListenerInvoke.messageMap.get(key); synchronized (messageList) { if (ListenerInvoke.messageMap.get(key) != null) { messageList.add(content); if (!ReadConfig.threadDeleteMessCacheOrFIFO && messageList.size() >= ReadConfig.messageCacheSizeLimit) messageList.remove(0); } } } if (!ListenerInvoke.messageMapKeyList.contains(key)) { synchronized (ListenerInvoke.messageMapKeyList) { if (!ListenerInvoke.messageMapKeyList.contains(key)) ListenerInvoke.messageMapKeyList.add(key); } } } /** * 接收message * @return Message */private boolean getMessage() { InputStream is = null; DataInputStream di = null; Message message = null; try { if (this.socket == null) return false; is = this.socket.getInputStream(); if (is == null) return false; di = new DataInputStream(is); byte[] temp = new byte[1]; int flag = 0; ArrayList tempByteList = new ArrayList(); int i = 0; while (flag != -1) { i++; flag = di.read(temp = new byte[1]); if (flag != -1) tempByteList.add(temp); if (i == 38) break; } if (i == 1) return false; tempByteList = new ArrayList(); i = 0; while (flag != -1) { i++; flag = di.read(temp = new byte[1]); if (flag != -1) tempByteList.add(temp); if (i == 74) break; } byte[] length = new byte[4]; di.read(length); int len = Integer.parseInt(new String(length, MessageFactory.DEFAULT_CHAR_SET).trim()); flag = 0; for (int j = 0; j < len; j++) { flag = di.read(temp = new byte[1]); if (flag == -1) break; tempByteList.add(temp); } message = MessageFactory.readMessage(tempByteList, len); SwingUtils.appendLog(MainForm.jTextArea, "收到新 Message", ReadConfig.commandStateShowLineCount); distributeMess(message);// 分发message } catch (IOException e) { e.printStackTrace(); } finally { } return true; } /** * 负责发送请求接收反馈的内部线程类，每new一个RequestSocketThread线程， * 就new一个socket，建立一条专属连接，成功接收反馈后将销毁socket，终止线程。 * 将发送请求，接收反馈放进内部线程处理，是为了防止套接字阻塞造成主线程挂死。 * @author cuishen * @version 1.2 */class RequestSocketThread implements Runnable { private SocketFactory socketFactory; private String commandType = null; private String commandContent = null; private String targetIP = null; Thread t; public RequestSocketThread(String commandType, String commandContent, String targetIP, int targetPort) { this.socketFactory = new SocketFactory(); try { this.socketFactory.connect(ReadConfig.targetIpAddress, ReadConfig.targetPort); } catch (UnknownHostException e) { SwingUtils.Error("主机 IP 地址无法确定,无法建立连接！ targetIP=" + ReadConfig.targetIpAddress + ", targetPort=" + ReadConfig.targetPort); e.printStackTrace(); } catch (IOException e) { SwingUtils.Error("访问被拒绝，无法建立连接，请检查网络！ targetIP=" + ReadConfig.targetIpAddress + ", targetPort=" + ReadConfig.targetPort); e.printStackTrace(); } this.commandType = commandType; this.commandContent = commandContent; this.targetIP = targetIP; t = new Thread(this); t.start(); } public void run() { this.socketFactory.sendRequest(commandType, commandContent, targetIP); this.socketFactory.getResponse(); stopThread(); } public void stopThread() { try { this.commandType = null; this.commandContent = null; this.targetIP = null; socketFactory.closeSocket(); socketFactory = null; this.t.join(100); } catch (InterruptedException e) { e.printStackTrace(); } finally { t = null; } } } /** * 负责接收message的内部线程类，每new一个GetMessageSocketThread线程， * 就new一个socket，建立一条专属TCP/IP连接，getMessage是长连接，所以建议 * 将该线程放入缓存方便管理 * @author cuishen * @version 1.2 */class GetMessageSocketThread implements Runnable { private SocketFactory socketFactory; private String commandType = null; private String commandContent = null; private String targetIP = null; Thread t; private boolean flag = false; private boolean ifGetResponse = true; private boolean ifGetMessage = true; private boolean ifSendRequest = true; private boolean ifCycle = true; public GetMessageSocketThread(String commandType, String commandContent, String targetIP, int targetPort) { this.socketFactory = new SocketFactory(); try { this.socketFactory.connect(ReadConfig.targetIpAddress, ReadConfig.targetPort); } catch (UnknownHostException e) { SwingUtils.Error("主机 IP 地址无法确定,无法建立连接！ targetIP=" + ReadConfig.targetIpAddress + ", targetPort=" + ReadConfig.targetPort); e.printStackTrace(); } catch (IOException e) { SwingUtils.Error("访问被拒绝，无法建立连接，请检查网络！ targetIP=" + ReadConfig.targetIpAddress + ", targetPort=" + ReadConfig.targetPort); e.printStackTrace(); } this.commandType = commandType; this.commandContent = commandContent; this.targetIP = targetIP; t = new Thread(this); t.start(); } public void run() { while (ifCycle) { if (ifSendRequest) { this.socketFactory.sendRequest(commandType, commandContent, targetIP); ifSendRequest = false; } if (ifGetResponse) { flag = socketFactory.getResponse(); ifGetResponse = false; } if (flag && ifGetMessage && socketFactory.socket != null) { if (!socketFactory.getMessage()) { try { Thread.sleep(ReadConfig.getMessageThreadSleep); } catch (InterruptedException e) { e.printStackTrace(); } } } } } public void stopThread() { try { this.commandType = null; this.commandContent = null; this.targetIP = null; ifGetMessage = false; ifCycle = false; socketFactory.closeSocket(); socketFactory = null; this.t.join(100); } catch (InterruptedException e) { e.printStackTrace(); } finally { t = null; } } } /** * 关闭套接字 */private void closeSocket() { try { if (!socket.isClosed()) socket.close(); socket = null; } catch (IOException e) { e.printStackTrace(); } } /** * @return the targetIpAddress */public String getTargetIpAddress() { return targetIpAddress; } /** * @param targetIpAddress * the targetIpAddress to set */public void setTargetIpAddress(String targetIpAddress) { this.targetIpAddress = targetIpAddress; } /** * @return the targetPort */public int getTargetPort() { return targetPort; } /** * @param targetPort * the targetPort to set */public void setTargetPort(int targetPort) { this.targetPort = targetPort; } } |
以上是Socket编程，ServerSocket在项目里没有用到，但是我也写了个包装类供参考
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package com.sse.monitor.serv; import java.io.IOException; import java.net.ServerSocket; import java.net.Socket; /** * 服务器套接字工厂 * Copyright: Copyright (c) 2008 * @author cuishen * @version 1.0 */public class ServerSocketFactory { private static ServerSocket server; private static Socket client; private boolean ifRunServer = true; public void runServer(int port) throws IOException { //本地建立一个套接字服务器，等待其他机器访问 server = new ServerSocket(port); System.out.println("Socket Server Start..."); new ServerThread(); } class ServerThread implements Runnable { Thread t; public ServerThread() { t = new Thread(this); t.start(); } public void run() { try { while(ifRunServer) { if(client == null) client = server.accept(); if(client != null) //getMessage(); Thread.sleep(ReadConfig.serverThreadSleep); } } catch (InterruptedException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } public void stopThread() { try { ifRunServer = false; this.t.join(100); } catch (InterruptedException ex) { System.out.println("socket服务器线程终止异常！！！"); } finally { t = null; } } } } |
Socket编程就是运用Socket或者ServerSocket类搭配线程来使用(由于TCP/IP属于可靠性传输，不会丢包)。可能会因为在发送请求或者接受消息时Socket阻塞而导致主线程挂死，因此发送请求、接收消息的方法要放进子线程里处理；对于同一目标ip和端口，在同一个子线程里只能new一个Socket，也就是说，要对同一地址建立多条连接，就要开启多个线程。而且注意连接可能会因作用不同分长连接和短连接，要分别处理，本项目中发送请求和接受message就分别属于短连接和长连接，因此分别开发了RequestSocketThread和GetMessageSocketThread两个子线程区分对待。可以同时开发个Message类来封装打包和解包消息的方法(项目中开发MessageFactory.java)，方便调用