通信

• • TCP/IP
  • • • TCP/IP協(xié)議集的主要協(xié)議
  • OSI（開放系統(tǒng)互連參考模型）
  • TCP協(xié)議建立連接的三次握手
  • 通信的分類
  • UDP通信
  • • • send端
      • receive端
      • 設計報頭
      • 案例（屏幕廣播，紅蜘蛛）
      • • • 需要掌握的其他技術
      • 代碼實現(xiàn)
      • • • 教師端
          • 學生端
  • TCP通信
  • • • QQ案例
      • • • 設計報頭
          • 需要掌握的其他技術
          • QQServer
          • QQClient

TCP/IP

• TCP：傳輸控制協(xié)議
• IP：網(wǎng)絡協(xié)議

TCP/IP協(xié)議集的主要協(xié)議

協(xié)議提供服務相應OSI層

IP	數(shù)據(jù)報服務	3
ICMP	差錯和控制	3
ARP	互聯(lián)網(wǎng)地址 -> 物理地址	3
RARP	物理地址 -> 互聯(lián)網(wǎng)地址	3
TCP	可靠流服務	4
FTP	文件傳送	5~7
TELNET	終端仿真	5~7
DNS	域名 -> 互聯(lián)網(wǎng)地址	5~7

OSI（開放系統(tǒng)互連參考模型）

OSI分為七層結構，分別是：

• 物理層：規(guī)范有關傳輸介質(zhì)的特性標準
• 數(shù)據(jù)鏈路層：定義了在單個鏈路上如何傳輸數(shù)據(jù)：SPX
• 網(wǎng)絡層：對端到端的包傳輸進行定義，定義了能夠標識所有結點的邏輯地址，定義了路由實現(xiàn)的方式和學習的方式，定義了如何將一個包分解成更小的包的分段方法：IP，IPX
• 傳輸層：UDP(無連接，用于廣播，無固定路由)，TCP（面向連接，三次握手，身份識別）
• 會話層：
• 表示層：
• 應用層：http，https，ftp，SMTP

TCP協(xié)議建立連接的三次握手

A發(fā)送syn信號x給B

B接收A的syn信號x，構造一個ack信號（x + 1），準備自己的syn信號y

B向A發(fā)送x + 1和 y的信號

A接收B的ack + syn信號，對B的身份進行認證，同時構造ack( y + 1)

A發(fā)送 ack( y + 1)給B

B認證A的身份

通信的分類

• 單工：單項通信，只能收不能發(fā)
• 雙工：雙向通信，既可以收也可以發(fā)
  • 半雙工：同一時刻，只能收或者只能發(fā)
  • 全雙工：同一時刻，既可以收也可以發(fā)

UDP通信

UPD通信一般用于屏幕廣播，UDP通信的特點是發(fā)完就結束，不管接收端收不收到，每個發(fā)送的數(shù)據(jù)有64k上限，發(fā)送的包無序

send端

import java.io.ByteArrayInputStream; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetSocketAddress;/*** Create Time: 2020.06.07 09:38* 發(fā)送端**/ public class Sender {public static void main(String[] args) throws Exception {//數(shù)據(jù)報套接字，指定發(fā)送端的發(fā)送端口9999DatagramSocket socket = new DatagramSocket(9999);String data = "6月6日0—24時，31個省（自治區(qū)、直轄市）和新疆生產(chǎn)建設兵團報告新增確診病例6例，其中境外輸入病例5例（陜西2例，天津1例，福建1例，廣東1例），本土病例1例（在海南）；無新增死亡病例；新增疑似病例2例，均為境外輸入病例（均在上海)。當日新增治愈出院病例3例，解除醫(yī)學觀察的密切接觸者633人，重癥病例減少1例。境外輸入現(xiàn)有確診病例66例（無重癥病例），現(xiàn)有疑似病例3例。累計確診病例1776例，累計治愈出院病例1710例，無死亡病例。截至6月6日24時，據(jù)31個省（自治區(qū)、直轄市）和新疆生產(chǎn)建設兵團報告，現(xiàn)有確診病例70例（無重癥病例），累計治愈出院病例78332例，累計死亡病例4634例，累計報告確診病例83036例，現(xiàn)有疑似病例3例。累計追蹤到密切接觸者746744人，尚在醫(yī)學觀察的密切接觸者3389人。31個省（自治區(qū)、直轄市）和新疆生產(chǎn)建設兵團報告新增無癥狀感染者5例（境外輸入4例）；當日轉(zhuǎn)為確診病例1例；當日解除醫(yī)學觀察25例（境外輸入2例）；尚在醫(yī)學觀察無癥狀感染者236例（境外輸入43例）。累計收到港澳臺地區(qū)通報確診病例1593例。其中，香港特別行政區(qū)1105例（出院1048例，死亡4例），澳門特別行政區(qū)45例（出院45例），臺灣地區(qū)443例（出院429例，死亡7例）。";ByteArrayInputStream bis = new ByteArrayInputStream(data.getBytes());//構造數(shù)據(jù)緩沖區(qū)，形成數(shù)據(jù)報包byte[] buf = new byte[1024];int len = 0;//192.168.12.255 255指給192.168.12這個網(wǎng)段的所有ip進行廣播發(fā)送InetSocketAddress address = new InetSocketAddress("localhost", 8888);while ((len = bis.read(buf)) != -1){//數(shù)據(jù)報包，參數(shù)：緩沖區(qū)，長度DatagramPacket packet = new DatagramPacket(buf,len);//數(shù)據(jù)報包中包含接收端的地址和端口packet.setSocketAddress(address);socket.send(packet);}} }

receive端

import java.net.DatagramPacket; import java.net.DatagramSocket;/*** Create Time: 2020.06.07 09:50* 接收方**/ public class Receiver {public static void main(String[] args) throws Exception {DatagramSocket socket = new DatagramSocket(8888);//數(shù)據(jù)接收緩沖區(qū)byte[] bytes = new byte[1024];String str = "";while(true){//接收方需要先創(chuàng)建一個空包去接收數(shù)據(jù)DatagramPacket packet = new DatagramPacket(bytes,bytes.length);socket.receive(packet);int dataLen = packet.getLength();str = new String(bytes, 0, dataLen);System.out.println("收到了："+str);}} }

設計報頭

報頭需要的元素：

• 幀的id，8個字節(jié)，可以用時間戳表示，一幀代表一組數(shù)據(jù)
• 幀單元個數(shù)，1個字節(jié)
• 幀單元編號，1個字節(jié)，編號是連續(xù)的，幀單元是一組數(shù)據(jù)被切割成若干個包，每個包就是一個幀單元，用編號來確定包的順序
• 幀單元數(shù)據(jù)長度，4個字節(jié)
• 幀數(shù)據(jù)，最多60K

案例（屏幕廣播，紅蜘蛛）

需要掌握的其他技術

截屏：

import javax.imageio.ImageIO; import java.awt.*; import java.awt.image.BufferedImage; import java.io.FileOutputStream;Robot robot = new Robot();//獲取屏幕的分辨率int width = Toolkit.getDefaultToolkit().getScreenSize().width;int height = Toolkit.getDefaultToolkit().getScreenSize().height;//截屏,參數(shù)：坐標+分辨率BufferedImage image = robot.createScreenCapture(new Rectangle(0, 0, width, height));//保存圖片，參數(shù)：BufferedImage，圖片格式，圖片路徑輸出流ImageIO.write(image,"jpg",new FileOutputStream("d:/1.jpg"));

字節(jié)數(shù)組與長整形的轉(zhuǎn)換：

/*** 將長整形轉(zhuǎn)換成字節(jié)數(shù)組* @param i*/public static byte[] long2Bytes(long i){byte[] arr = new byte[8];arr[0] = (byte)i;arr[1] = (byte)(i >> 8);arr[2] = (byte)(i >> 16);arr[3] = (byte)(i >> 24);arr[4] = (byte)(i >> 32);arr[5] = (byte)(i >> 40);arr[6] = (byte)(i >> 48);arr[7] = (byte)(i >> 56);return arr;}/*** 將字節(jié)數(shù)組轉(zhuǎn)換成長整形*/public static long bytes2long(byte[] arr){long i0 = (long)(arr[0] & 0xFF);//這個long必須要放在里面，要先將其轉(zhuǎn)為long再移動字節(jié)，不然是無法滿足那么多位讓你去移動的long i1 = ((long)(arr[1] & 0xFF) << 8);long i2 = ((long)(arr[2] & 0xFF) << 16);long i3 = ((long)(arr[3] & 0xFF) << 24);long i4 = ((long)(arr[4] & 0xFF) << 32);long i5 = ((long)(arr[5] & 0xFF) << 40);long i6 = ((long)(arr[6] & 0xFF) << 48);long i7 = ((long)(arr[7] & 0xFF) << 56);return i0 | i1 | i2 | i3 | i4 | i5 | i6 | i7;}

壓縮字節(jié)與解壓縮字節(jié)：

/*** 壓縮字節(jié)*/public static byte[] zipData(byte[] zipData){try{ByteArrayOutputStream baos = new ByteArrayOutputStream();ZipOutputStream zos = new ZipOutputStream(baos);zos.putNextEntry(new ZipEntry("one"));zos.write(zipData);zos.close();return baos.toByteArray();}catch (Exception e){e.printStackTrace();}return null;}/*** 解壓縮*/public static byte[] unzipData(byte[] rawData){try {ByteArrayInputStream bais = new ByteArrayInputStream(rawData);ZipInputStream zis = new ZipInputStream(bais);ByteArrayOutputStream baos = new ByteArrayOutputStream();zis.getNextEntry();byte[] buf = new byte[1024];int len = 0;while ((len = zis.read(buf)) != -1){baos.write(buf,0,len);}zis.close();bais.close();baos.close();return baos.toByteArray();}catch (Exception e){e.printStackTrace();}return null;}

代碼實現(xiàn)

教師端

import javax.imageio.ImageIO; import java.awt.*; import java.awt.image.BufferedImage; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetSocketAddress; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map;/*** Create Time: 2020.06.07 14:57** 屏幕廣播* 發(fā)送方**/ public class SenderPG {//每個幀單元的最大值60Kprivate static int frame_UNIT_MAX = 60 * 1024;//截屏需要的機器人類private static Robot robot = null;//屏幕的分辨率private static int width = 0;private static int height = 0;//UDP廣播需要的連接private static DatagramSocket socket = null;static {try {robot = new Robot();//獲取屏幕分辨率width = Toolkit.getDefaultToolkit().getScreenSize().width;height = Toolkit.getDefaultToolkit().getScreenSize().height;//設置發(fā)送端的端口為8888socket = new DatagramSocket(8888);} catch (Exception e) {e.printStackTrace();}}public static void main(String[] args) throws Exception {while (true){sendOneScreenData();}}/*** 發(fā)送一屛數(shù)據(jù)* 1. 截屏* 2. 切屏（切屏之前先壓縮截屏數(shù)據(jù)，減小網(wǎng)絡傳輸?shù)膲毫?#xff09;* 3. 組裝UdpPackage （8 + 1 + 1 + 4 + n）* 4. 發(fā)送*/private static void sendOneScreenData() {byte[] bytes = null;List<Map<String,Object>> maps = null;try {//1. 截屏bytes = captureScreen();//2. 切屏if(bytes != null && bytes.length > 0){//切屏之前先壓縮字節(jié)，將網(wǎng)絡傳輸?shù)膲毫D(zhuǎn)移到cpu上maps = splitFrame(Util.zipData(bytes));}//發(fā)送if(maps != null && maps.size() > 0){sendUnits(maps);}} catch (Exception e) {e.printStackTrace();}}/*** 發(fā)送數(shù)據(jù)* @param maps*/private static void sendUnits(List<Map<String, Object>> maps) {try {//客戶端的地址是本地地址，端口號9999InetSocketAddress address = new InetSocketAddress("localhost", 9999);for(Map<String,Object> map:maps){//組裝幀單元數(shù)據(jù)到字節(jié)數(shù)組byte[] bytes = propFrameUnit(map);DatagramPacket packet = new DatagramPacket(bytes,bytes.length);packet.setSocketAddress(address);socket.send(packet);}} catch (Exception e) {e.printStackTrace();}}/*** 組裝幀單元數(shù)據(jù)到字節(jié)數(shù)組* @param map* @return*/private static byte[] propFrameUnit(Map<String, Object> map) {byte[] bytes = new byte[14 + Integer.parseInt(BlankNull(map.get("frameLength")))];//framIdbyte[] frameIds = Util.long2Bytes((long) map.get("frameId"));System.arraycopy(frameIds,0,bytes,0,frameIds.length);//frameCountbyte frameCount = (byte) map.get("frameCount");bytes[frameIds.length] = frameCount;//frameNobyte frameNo = (byte) map.get("frameNo");bytes[frameIds.length + 1] = frameNo;//frameLengthbyte[] frameLengths = Util.int2Bytes((int) map.get("frameLength"));System.arraycopy(frameLengths,0,bytes,frameIds.length + 2,frameLengths.length);//frameDatabyte[] frameData = (byte[]) map.get("frameData");System.arraycopy(frameData,0,bytes,frameIds.length + 2 + frameLengths.length,frameData.length);return bytes;}/*** 非空判斷* @param obj* @return*/private static String BlankNull(Object obj) {if(obj != null){return obj.toString();}else{return "";}}/*** 切屏* @param bytes* @return*/private static List<Map<String, Object>> splitFrame(byte[] bytes) {List<Map<String, Object>> resultList = new ArrayList<>();long frameId = System.currentTimeMillis();//判斷數(shù)據(jù)是否大于60Kif(bytes.length > frame_UNIT_MAX){//切//求需要切除的個數(shù)byte count = (byte)(bytes.length / frame_UNIT_MAX);int ys = bytes.length % frame_UNIT_MAX;if( ys != 0) {count ++;}for(byte i = 0; i < count;i++){//map中包含：幀id（每一屏的數(shù)據(jù)為一幀，取當前的時間戳，8個字節(jié)），幀單元的數(shù)量（1個字節(jié)），幀單元的編號（1個字節(jié)），幀單元數(shù)據(jù)的大小（除了最后一個，前面的幀單元都是最大值60K），幀單元的數(shù)據(jù)Map<String, Object> map = new HashMap<>();map.put("frameId",frameId);map.put("frameCount",count);map.put("frameNo",i);if(i == (count - 1) && ys != 0){map.put("frameLength", ys);byte[] data = new byte[ys];System.arraycopy(bytes,i*frame_UNIT_MAX,data,0,ys);map.put("frameData",data);}else{map.put("frameLength",frame_UNIT_MAX);byte[] data = new byte[frame_UNIT_MAX];System.arraycopy(bytes,i*frame_UNIT_MAX,data,0,frame_UNIT_MAX);map.put("frameData",data);}resultList.add(map);}}else{//不切Map<String, Object> map = new HashMap<>();map.put("frameId",frameId);map.put("frameCount",1);map.put("frameNo",0);map.put("frameLength",bytes.length);map.put("frameData",bytes);resultList.add(map);}return resultList;}/*** 截屏* @return*/private static byte[] captureScreen() throws IOException {BufferedImage image = robot.createScreenCapture(new Rectangle(0, 0, width, height));ByteArrayOutputStream baos = new ByteArrayOutputStream();ImageIO.write(image,"jpg",baos);return baos.toByteArray();}

學生端

import java.awt.image.BufferedImage; import java.io.ByteArrayOutputStream; import java.io.FileOutputStream; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.SocketException; import java.util.*;/*** Create Time: 2020.06.07 14:58* * 屏幕廣播* 接收方**/ //使用線程是為了防止接收端占用主線程導致線程阻塞阻礙其他項目的運行 public class ReceiverPG extends Thread {private DatagramSocket socket = null;private DatagramPacket packet = null;//一個幀單元數(shù)據(jù)的最大長度private final static int frame_UNIT_MAX = 60 * 1024;//幀單元緩沖區(qū)，數(shù)據(jù)最大長度+報頭長度private byte[] buf = new byte[frame_UNIT_MAX + 14];public ReceiverPG() {try {//設置接收端的端口為9999this.socket = new DatagramSocket(9999);this.packet = new DatagramPacket(buf,buf.length);} catch (SocketException e) {e.printStackTrace();}}@Overridepublic void run() {receiver();}public void receiver(){Map<Integer, Map<String, Object>> resultMap = new HashMap<>();//記錄當前獲取的幀單元的idlong currentFrameId = 0L;while (true){try {socket.receive(packet);//整合幀單元Map<String, Object> map = propFrameUnit();long frameId = Long.parseLong(Util.BlankNull(map.get("frameId")));int frameCount = Integer.parseInt(Util.BlankNull(map.get("frameCount")));int frameNo = Integer.parseInt(Util.BlankNull(map.get("frameNo")));//判斷當前接收的對象是否屬于同一幀if( frameId == currentFrameId){//是就存儲resultMap.put(frameNo,map);}else if(frameId > currentFrameId){//如果不是，取最新的幀，放棄原來的幀單元currentFrameId = frameId;resultMap.clear();resultMap.put(frameNo,map);}//判斷同一幀數(shù)據(jù)是否收集完畢，完畢則組裝數(shù)據(jù)，還原截圖if(resultMap.keySet().size() == frameCount){//組裝截屏數(shù)據(jù)propData(resultMap);resultMap.clear();}} catch (Exception e) {e.printStackTrace();}}}/*** 組裝圖片數(shù)據(jù)* @param maps* @return*/private BufferedImage propData(Map<Integer, Map<String, Object>> maps) {BufferedImage bufferedImage = null;try {String pictureName = (new Date()).getTime() + ".jpg";System.out.println("保存一張圖片"+pictureName);FileOutputStream fos = new FileOutputStream("D:\\aa\\pg\\" + pictureName);ByteArrayOutputStream baos = new ByteArrayOutputStream();for(int i = 0; i < maps.size();i++){byte[] bytes = (byte[]) maps.get(i).get("frameData");baos.write(bytes);}//拿到截屏字節(jié)，發(fā)送端壓縮過，所以接收端要解壓fos.write(Util.unzipData(baos.toByteArray()));baos.close();fos.close();} catch (Exception e) {e.printStackTrace();}return bufferedImage;}/*** 整合幀單元* @return*/private Map<String, Object> propFrameUnit() {Map<String, Object> map = new HashMap<>();byte[] frameIds = new byte[8];System.arraycopy(buf,0,frameIds,0,8);long frameId = Util.bytes2long(frameIds);byte frameCount = buf[8];byte frameNo = buf[9];byte[] frameLengths = new byte[4];System.arraycopy(buf,10,frameLengths,0,4);int frameLength = Util.Bytes2int(frameLengths);byte[] frameData = new byte[frameLength];System.arraycopy(buf,14,frameData,0,frameLength);map.put("frameId",frameId);map.put("frameCount",frameCount);map.put("frameNo",frameNo);map.put("frameLength",frameLength);map.put("frameData",frameData);return map;}public static void main(String[] args) {new ReceiverPG().start();} }

TCP通信

使用TCP通信最常見的應用就是QQ

QQ案例

設計報頭

報頭需要的元素：

• 消息類型，4個字節(jié)，（單發(fā)、群發(fā)、刷新好友列表）
• 接收方信息長度
• 接收方信息
• 消息長度，4個字節(jié)
• 消內(nèi)容
• 發(fā)送方信息長度
• 發(fā)送方信息

需要掌握的其他技術

java串行化
java串行化是指將一個對象拆分為字節(jié)數(shù)組，然后轉(zhuǎn)為流的形式，可以拆分為字節(jié)數(shù)組的對象必須實現(xiàn) Serializable接口

/*** 串行化對象*/public static byte[] serializeObject(Serializable src){try {ByteArrayOutputStream baos = new ByteArrayOutputStream();ObjectOutputStream oos = new ObjectOutputStream(baos);oos.writeObject(src);oos.close();baos.close();return baos.toByteArray();} catch (Exception e) {e.printStackTrace();}return null;}/*** 反串行化*/public static Serializable deSerializeObject(byte[] bytes){try {ByteArrayInputStream bais = new ByteArrayInputStream(bytes);ObjectInputStream ois = new ObjectInputStream(bais);Serializable s = (Serializable) ois.readObject();ois.close();bais.close();return s;} catch (Exception e) {e.printStackTrace();}return null;}

QQServer

import java.io.IOException; import java.io.OutputStream; import java.net.InetSocketAddress; import java.net.ServerSocket; import java.net.Socket;/*** Create Time: 2020.06.14 09:26** QQ服務器**/ public class QQServer {//維護所有的客戶端集合//key是ip+端口號private static Map<String,Socket> socketMap = new HashMap<>();public static Map<String, Socket> getSocketMap() {return socketMap;}public static void main(String[] args) {try {//設置QQ服務器端口為8888ServerSocket ss = new ServerSocket(8888);while (true){//阻塞Socket socket = ss.accept();InetSocketAddress isa = (InetSocketAddress)socket.getRemoteSocketAddress();String ip = isa.getAddress().getHostAddress();int port = isa.getPort();String key = ip + ":" + port;//將上線的客戶端都維護到這個集合中去socketMap.put(key,socket);//處理客戶端來的消息，這里必須要開分線程，因為客戶端不可能只有一個//參數(shù)當前發(fā)送消息的客戶端的socket和他對應的key(new CommThread(socket,key)).start();}}catch (Exception e){e.printStackTrace();}}//服務器向客戶端發(fā)送消息public static void sendMessage(Socket socket, byte[] bytes){try {OutputStream os = socket.getOutputStream();os.write(bytes);//清理os.flush();} catch (IOException e) {e.printStackTrace();}} } import java.io.InputStream; import java.net.Socket;/*** Create Time: 2020.06.14 09:52***/ public class CommThread extends Thread {private Socket socket = null;private String sender = null;public CommThread(Socket socket,String sender){this.socket = socket;this.sender = sender;}@Overridepublic void run() {try {while (true){InputStream is = socket.getInputStream();//解析客戶端發(fā)送過來的消息并發(fā)送MessageFactory.serverParseMessage(is,sender);}} catch (Exception e) {e.printStackTrace();}} } /*** 服務器解析消息* @param is* is中包含消息類型、（接收方信息長度、接收方信息）、消息長度、消息內(nèi)容、發(fā)送方信息長度、發(fā)送方信息*/public static void serverParseMessage(InputStream is,String sender){try {if(is.available() > 0){byte[] xxBytes = new byte[is.available()];is.read(xxBytes);byte[] senderBytes = sender.getBytes();byte[] senderLengthBytes = Util.int2Bytes(senderBytes.length);//讀取消息類型byte[] xxlxBytes = new byte[4];System.arraycopy(xxBytes,0,xxlxBytes,0,4);int xxlx = Util.Bytes2int(xxlxBytes);switch (xxlx){/*** 0：私聊 需要解析接收端信息，以便發(fā)給接收端，并同時附加發(fā)送端信息* 1：群聊 ，附加發(fā)送方信息，遍歷好友列表，并發(fā)送* 2：刷新好友列表 //上線和下線*/case 0: {//讀取接收端用戶信息的長度byte[] receiverYHXXCDBytes = new byte[4];System.arraycopy(xxBytes,4,receiverYHXXCDBytes,0,4);int receiverYHXXLength = Util.Bytes2int(receiverYHXXCDBytes);//讀取接收端用戶信息byte[] receiverBytes = new byte[receiverYHXXLength];System.arraycopy(xxBytes,8,receiverBytes,0,receiverYHXXLength);String receiver = new String(receiverBytes, 0, receiverYHXXLength);Socket socket = QQServer.getSocketMap().get(receiver);//附加發(fā)送方位發(fā)送方信息byte[] bytes = new byte[xxBytes.length + 4 + senderBytes.length];System.arraycopy(xxBytes,0,bytes,0,xxBytes.length);System.arraycopy(senderLengthBytes,0,bytes,xxBytes.length,4);System.arraycopy(senderBytes,0,bytes,xxBytes.length + 4,senderBytes.length);if (socket != null) {QQServer.sendMessage(socket, bytes);}break;}case 1: {byte[] bytes = new byte[xxBytes.length + 4 + senderBytes.length];System.arraycopy(xxBytes,0,bytes,0,xxBytes.length);System.arraycopy(senderLengthBytes,0,bytes,xxBytes.length,4);System.arraycopy(senderBytes,0,bytes,xxBytes.length + 4,senderBytes.length);for (Socket client : QQServer.getSocketMap().values()) {QQServer.sendMessage(client, bytes);}break;}case 2:{List<String> clients = new ArrayList<>(QQServer.getSocketMap().keySet());byte[] bytes = Util.serializeObject((Serializable) clients);//將消息類型與好友列表組裝起來byte[] message = new byte[4 + bytes.length];System.arraycopy(xxlxBytes,0,message,0,4);System.arraycopy(bytes,0,message,4,bytes.length);for(Socket client:QQServer.getSocketMap().values()){QQServer.sendMessage(client,message);}break;}}}} catch (Exception e) {e.printStackTrace();}}

QQClient

import java.io.IOException; import java.io.OutputStream; import java.net.Socket;/*** Create Time: 2020.06.14 09:26** QQ客戶端**/ public class QQClient {//好友列表private static List<String> friends = null;public static void setFriends(List<String> friends) {QQClient.friends = friends;}public static void main(String[] args) throws Exception {Socket socket = new Socket("localhost", 8888);//獲取服務端發(fā)送過來的消息，這里也必須開啟線程，因為客戶端需要發(fā)送消息，不開線程這里就會堵塞，客戶端無法發(fā)送消息new Thread(new CommThread(socket)).start();Map<String, String> map = new HashMap<>();//上線，刷新好友列表map.put("xxlx","2");byte[] bytes = MessageFactory.fzxx(map);//向服務器發(fā)送消息sendMessage(socket,bytes);//請選擇發(fā)送方式System.out.println("0：單發(fā)；1：群發(fā)");Scanner scanner = new Scanner(System.in);String xxlx = scanner.nextLine();String fsdx = "";if(xxlx.equals("0")){//單發(fā)指定發(fā)送對象System.out.println("請選擇發(fā)送對象");String fsdxIndex = scanner.nextLine();fsdx = friends.get(Integer.parseInt(fsdxIndex) - 1);}//輸入消息System.out.println("請輸入發(fā)送消息");String message = scanner.nextLine();//封裝消息為字節(jié)數(shù)組map.put("xxlx",xxlx);map.put("fsdx",fsdx);map.put("message",message);bytes = MessageFactory.fzxx(map);//發(fā)送消息sendMessage(socket,bytes);}//客戶端向服務器發(fā)送消息public static void sendMessage(Socket socket, byte[] bytes){try {OutputStream os = socket.getOutputStream();os.write(bytes);//清理os.flush();} catch (IOException e) {e.printStackTrace();}} } import java.io.InputStream; import java.net.Socket;/*** Create Time: 2020.06.14 09:52***/ public class CommThread extends Thread {private Socket socket = null;public CommThread(Socket socket){this.socket = socket;}@Overridepublic void run() {try {while (true){InputStream is = socket.getInputStream();//解析服務端發(fā)送過來的消息MessageFactory.clientParseMessage(is);}} catch (Exception e) {e.printStackTrace();}} } /*** 客戶端解析消息* @param is* @return map中包含消息類型、（接收方信息長度、接收方信息）、消息長度、消息內(nèi)容、發(fā)送方信息長度、發(fā)送方信息*/public static void clientParseMessage(InputStream is){try {if(is.available() > 0){byte[] xxBytes = new byte[is.available()];is.read(xxBytes);//讀取消息類型byte[] xxlxBytes = new byte[4];System.arraycopy(xxBytes,0,xxlxBytes,0,4);int xxlx = Util.Bytes2int(xxlxBytes);switch (xxlx){//0：私聊case 0:{//讀取接收端用戶信息的長度byte[] receiverYHXXCDBytes = new byte[4];System.arraycopy(xxBytes,4,receiverYHXXCDBytes,0,4);int receiverLength = Util.Bytes2int(receiverYHXXCDBytes);//讀取消息byte[] messageLengthBytes = new byte[4];System.arraycopy(xxBytes,8 + receiverLength,messageLengthBytes,0,4);int messageLength = Util.Bytes2int(messageLengthBytes);byte[] messageBytes = new byte[messageLength];System.arraycopy(xxBytes,12 + receiverLength,messageBytes,0,messageLength);String message = new String(messageBytes, 0, messageLength);System.arraycopy(xxBytes,12 + receiverLength,messageBytes,0,messageLength);//讀取發(fā)送方信息byte[] senderLengthBytes = new byte[4];System.arraycopy(xxBytes,12 + receiverLength + messageLength ,senderLengthBytes,0,4);int senderLength = Util.Bytes2int(senderLengthBytes);byte[] senderBytes = new byte[senderLength];System.arraycopy(xxBytes,16 + receiverLength + messageLength,senderBytes,0,senderLength);String sender = new String(senderBytes,0,senderLength);System.out.println(sender + "發(fā)送消息：" + message);break;}//1：群聊case 1:{//讀取消息byte[] messageLengthBytes = new byte[4];System.arraycopy(xxBytes,4 ,messageLengthBytes,0,4);int messageLength = Util.Bytes2int(messageLengthBytes);byte[] messageBytes = new byte[messageLength];System.arraycopy(xxBytes,8,messageBytes,0,messageLength);String message = new String(messageBytes, 0, messageLength);System.arraycopy(xxBytes,8 ,messageBytes,0,messageLength);//讀取發(fā)送方信息byte[] senderLengthBytes = new byte[4];System.arraycopy(xxBytes,8 + messageLength ,senderLengthBytes,0,4);int senderLength = Util.Bytes2int(senderLengthBytes);byte[] senderBytes = new byte[senderLength];System.arraycopy(xxBytes,12 + messageLength ,senderBytes,0,senderLength);String sender = new String(senderBytes,0,senderLength);System.out.println(sender + "發(fā)送消息：" + message);break;}//2：刷新好友列表case 2:{byte[] friendBytes = new byte[xxBytes.length - 4];System.arraycopy(xxBytes,4,friendBytes,0,friendBytes.length);List<String> hylbList = (List<String>)Util.deSerializeObject(friendBytes);QQClient.setFriends(hylbList);for (int i = 0; i < hylbList.size();i++) {System.out.print((i + 1) + ". "+hylbList.get(i)+"；");}System.out.println();}}}} catch (Exception e) {e.printStackTrace();}}/*** 客戶端封裝消息*/public static byte[] fzxx(Map<String,String> message){int xxlx = Integer.parseInt(message.get("xxlx"));byte[] xxlxBytes = Util.int2Bytes(xxlx);switch (xxlx){//0：私聊case 0:{byte[] fsdx = message.get("fsdx").getBytes();byte[] fsdxLengthBytes = Util.int2Bytes(fsdx.length);byte[] messages = message.get("message").getBytes();byte[] messageLengthBytes = Util.int2Bytes(messages.length);byte[] bytes = new byte[4 + 4 + fsdx.length + 4 + messages.length];//存入消息類型System.arraycopy(xxlxBytes,0,bytes,0,4);//存入接收方信息長度System.arraycopy(fsdxLengthBytes,0,bytes,4,4);//存入接收方信息System.arraycopy(fsdx,0,bytes,8,fsdx.length);//存入消息長度System.arraycopy(messageLengthBytes,0,bytes,8 + fsdx.length , messageLengthBytes.length);//存入消息System.arraycopy(messages,0,bytes,12 + fsdx.length,messages.length);return bytes;}//1：群聊case 1:{byte[] messages = message.get("message").getBytes();byte[] messageLengthBytes = Util.int2Bytes(messages.length);byte[] bytes = new byte[4 + 4 + messages.length];//存入消息類型System.arraycopy(xxlxBytes,0,bytes,0,4);//存入消息長度System.arraycopy(messageLengthBytes,0,bytes,4 , messageLengthBytes.length);//存入消息System.arraycopy(messages,0,bytes,8,messages.length);return bytes;}//2：刷新好友列表case 2:{return xxlxBytes;}}return null;}

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