一个项目看java TCP/IP Socket编程(1.3版)

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

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

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