Java BIO实现聊天程序
本文实例为大家分享了Java BIO实现聊天程序的具体代码，供大家参考，具体内容如下
我们使用一个聊天程序来说本文的主题
1、BIO 客户端服务器通讯
public class ChatServer {
public static void main(String[] args) throws IOException {
ServerSocket serverSocket = new ServerSocket(9000);
while (true) {
try {
System.out.println("聊天服务已启动，等待客户连接....");
Socket socket = serverSocket.accept();
System.out.printf("建立了与%s的连接!\n",socket.getRemoteSocketAddress());
loopReadRequest(socket);
} catch (IOException e) {
e.printStackTrace();
}
}
}
public static String loopReadRequest(Socket socket) throws IOException {
InputStreamReader reader = new InputStreamReader(socket.getInputStream());
StringBuilder sb = new StringBuilder();
char[] cbuf = new char[256];
// 循环读取socket的输入数据流
while (true) {
// read方法，读出内容写入 char 数组,read 方法会一直阻塞
// 直到有输入内容 或 发生I/O错误 或 输入流结束(对方关闭了socket)
// 正常读取时方法会返回读取的字符数,当输入流结束时(对方关闭了socket)方法返回 -1
int readed = reader.read(cbuf);
SocketAddress remoteSocketAddress = socket.getRemoteSocketAddress();
// 客户端执行了socket.close()
if (readed == -1) {
System.out.println(remoteSocketAddress + " 断开了连接!");
reader.close();
socket.close();
break;
}
String readedStr = new String(cbuf, 0, readed);
sb.append(readedStr);
// ready()用来判断流是否可被读取,如果reader缓冲区不是空则返回true，否则返回false
if (!reader.ready()) {//reader缓冲区为空，表示数据流已读完
// 数据流已读完,此时向客户端发送响应
socket.getOutputStream().write((remoteSocketAddress+"你好，"+sb+"已收到").getBytes());
System.out.println("收到内容:"+sb);
// 清除sb的内容，准备接收下一个请求内容
sb.setLength(0);
System.out.println("等待客户端消息....");
}
}
return sb.toString();
}
}
public class ChatClient {
public static void main(String[] args) {
try {
Socket socket = new Socket("localhost", 9000);
Scanner scanner = new Scanner(System.in);
while (true) {
System.out.print(">");
String line = scanner.nextLine();
if("".equals(line)){
continue;
}
if ("quit".equals(line)) {
scanner.close();
socket.close();
break;
}
socket.getOutputStream().write(line.getBytes());
System.out.println(readRequest(socket));
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static String readRequest(Socket socket) throws IOException {
InputStreamReader reader = new InputStreamReader(socket.getInputStream());
StringBuilder sb = new StringBuilder();
char[] cbuf = new char[256];
while (true) {
int readed = reader.read(cbuf);
// 读出内容写入 char 数组,read 方法会一直阻塞
// 直到有输入内容 或 发生I/O错误 或 输入流结束(对方关闭了socket)
// 正常读取，方法会返回读取的字符数，而当输入流结束(对方关闭了socket)则返回 -1
if (readed == -1) {
System.out.println(socket.getRemoteSocketAddress() + " 断开了连接!");
reader.close();
socket.close();
break;
}
String readedStr = new String(cbuf, 0, readed);
sb.append(readedStr);
if(!reader.ready()){
break;
}
}
return sb.toString();
}
}
ChatServer与ChatClient建立了长连接，且ChatServer阻塞等待ChatClient发送消息过来，程序中 Server端只能与一个Client建立连接。程序这么写，只能实现一个客户端和服务端进行通信。
如何支持多个Client的连接呢？ 使用独立的线程去读取socket
2、多线程实现单聊，群聊
单聊发送 格式：-c 对方端口号 消息内容， 群聊直接发送信息就可以了，具体发送逻辑看下面的程序
public class ChatServer {
private static Map<String, Socket> connnectedSockets = new ConcurrentHashMap<>();
public static void main(String[] args) throws IOException {
// 1、服务端初始化工作
ServerSocket serverSocket = new ServerSocket(9000);
ExecutorService executorService = getExecutorService();
// 2、主线程- 循环阻塞接收新的连接请求
while (true) {
Socket socket = serverSocket.accept();
cacheSocket(socket);
// 3、一个socket对应一个读取任务,交给线程池中的线程执行
// 如果使用fixed线程池,会操作读取任务分配不到线程的情况
// 现象就是发送的消息别人收不到（暂存在Socket缓存中）
executorService.submit(createLoopReadTask(socket));
}
}
private static Runnable createLoopReadTask(Socket socket) {
return new Runnable() {
public void run() {
try {
loopReadRequestAndRedirect(socket);
} catch (IOException e) {
e.printStackTrace();
}
}
};
}
private static ExecutorService getExecutorService() {
ExecutorService executorService = Executors.newCachedThreadPool();
int nThreads = Runtime.getRuntime().availableProcessors();
nThreads = 1;
// 如果只设置一个线程，那么最先连接进来的客户端可以发送消息
// 因为程序阻塞读取第一个socket连接的数据流，没有其他线程资源去读后面建立的socket了
executorService = Executors.newFixedThreadPool(nThreads);
return executorService;
}
private static void cacheSocket(Socket socket) {
SocketAddress remoteSocketAddress = socket.getRemoteSocketAddress();
String[] split = remoteSocketAddress.toString().split(":");
connnectedSockets.put(split[1], socket);
}
public static String loopReadRequestAndRedirect(Socket socket) throws IOException {
InputStreamReader reader = new InputStreamReader(socket.getInputStream());
StringBuilder sb = new StringBuilder();
char[] cbuf = new char[256];
while (true) {
SocketAddress remoteSocketAddress = socket.getRemoteSocketAddress();
System.out.println(Thread.currentThread() + "执行 " + remoteSocketAddress + "发送的消息");
// 读出内容写入 char 数组,read 方法会一直阻塞
// 直到有输入内容 或 发生I/O错误 或 输入流结束(对方关闭了socket)
// 正常读取时方法会返回读取的字符数，当输入流结束(对方关闭了socket)时返回 -1
int readed = reader.read(cbuf);
if (readed == -1) {
System.out.println(remoteSocketAddress + " 断开了连接!");
reader.close();
socket.close();
break;
}
String readedStr = new String(cbuf, 0, readed);
sb.append(readedStr);
//ready()用来判断流是否可被读取,如果reader缓冲区不是空则返回true，否则返回false
boolean oneReqeustStreamReaded = !reader.ready();
if (oneReqeustStreamReaded) {
String requestContent = sb.toString().trim();
String prifix = requestContent.substring(0, 2);
// 单聊
if ("-c".equals(prifix)) {
requestContent = requestContent.substring(3);
String port = requestContent.substring(0, requestContent.indexOf(" "));
requestContent = requestContent.replaceFirst(port, "");
sendToOneSocket(connnectedSockets.get(port), requestContent);
// 群聊
} else {
// 向客户端发送响应
socket.getOutputStream().write(("您发送的消息-'" + sb + "' 已收到").getBytes());
sendToAllSocket(sb.toString(), socket);
}
sb.setLength(0);
}
}
return sb.toString();
}
/**
* 发送消息给某个socket
*
* @param socket
* @param msg
*/
private static void sendToOneSocket(Socket socket, String msg) {
// 对于同一个socket,同一时刻只有一个线程使用它发送消息
synchronized (socket) {
try {
socket.getOutputStream().write(msg.getBytes("UTF-8"));
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 发送消息给所有的socket
*
* @param msg
*/
private static void sendToAllSocket(String msg, Socket selfSocket) {
for (String key : connnectedSockets.keySet()) {
Socket socket = connnectedSockets.get(key);
if (socket.equals(selfSocket)) {
continue;
}
sendToOneSocket(socket, msg);
}
}
}
public class ChatClient {
public static void main(String[] args) throws IOException {
new ChatClient().start();
}
public void start() throws IOException {
Socket socket = new Socket("localhost", 9000);
ExecutorService executorService = Executors.newFixedThreadPool(2);
Runnable readTask = new Runnable() {
public void run() {
try {
loopReadRequest(socket);
} catch (IOException e) {
e.printStackTrace();
}
}
};
executorService.submit(readTask);
Runnable sendMsgTask = new Runnable() {
public void run() {
try {
Scanner scanner = new Scanner(System.in);
while (true) {
System.out.print(">");
String line = scanner.nextLine();
if ("".equals(line)) {
continue;
}
if ("quit".equals(line)) {
scanner.close();
socket.close();
break;
}
socket.getOutputStream().write(line.getBytes());
}
} catch (IOException e) {
e.printStackTrace();
}
}
};
executorService.submit(sendMsgTask);
}
public void loopReadRequest(Socket socket) throws IOException {
InputStreamReader reader = new InputStreamReader(socket.getInputStream());
StringBuilder sb = new StringBuilder();
char[] cbuf = new char[256];
while (true) {
int readed = reader.read(cbuf);
// 读出内容写入 char 数组,read 方法会一直阻塞
// 直到有输入内容 或 发生I/O错误 或 输入流结束(对方关闭了socket)
// 正常读取，方法会返回读取的字符数，而当输入流结束(对方关闭了socket)则返回 -1
if (readed == -1) {
System.out.println(socket.getRemoteSocketAddress() + " 断开了连接!");
reader.close();
socket.close();
break;
}
String readedStr = new String(cbuf, 0, readed);
sb.append(readedStr);
if (!reader.ready()) {
System.out.println(sb);
sb.setLength(0);
}
}
}
}
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