- 本文讲述了从实现单个多个客户的收发信息（基础简易版），到各种实现代码的封装（oop版），实现群聊（群聊过渡版），到最后实现私聊（终极版）的过程
- 本文内容是在初步学习网络编程时，练习强化记忆时的学习总结
- 主要利用了TCP网络编程和多线程
- 如有问题，欢迎指出综合案例：在线聊天室
需求：使用TCP的Socket实现一个聊天室
- 服务器端：一个线程专门发送消息，一个线程专门接收消息
- 客户端：一个线程专门发送消息，一个线程专门接收消息
1. 基础简易版
1.1 一个客户收发多条消息
- 目标：实现一个客户可以正常收发多条信息
服务器
/**
* 在线聊天室： 服务器
* 目标：实现一个客户可以正常收发多条消息
* 服务器不生产内容，相当于一个转发站，将客户端的请求转发
*/
public class MutiChat {
public static void main(String[] args) throws IOException {
System.out.println("-----Server-----");
// 1、指定端口 使用ServerSocket创建服务器
ServerSocket server = new ServerSocket(8888);
// 2、利用Socket的accept方法，监听客户端的请求。阻塞，等待连接的建立
Socket client = server.accept();
System.out.println("一个客户端建立了连接");
DataInputStream dis = new DataInputStream(client.getInputStream());
DataOutputStream dos = new DataOutputStream(client.getOutputStream());
boolean isRunning = true;
while (isRunning) {
// 3、接收消息
String msg = dis.readUTF();
// 4、返回消息
dos.writeUTF(msg);
dos.flush();
}
// 5、释放资源
dos.close();
dis.close();
client.close();
}
}客户端
/**
* 在线聊天室： 客户端
* 目标：实现一个客户可以正常收发(多条)信息
*/
public class MutiClient {
public static void main(String[] args) throws IOException {
System.out.println("-----Client-----");
// 1、建立连接：使用Socket创建客户端 + 服务的地址和端口
Socket client = new Socket("localhost", 8888);
// 2、客户端发送消息
BufferedReader console = new BufferedReader(new InputStreamReader(System.in)); // 对接控制台
DataOutputStream dos = new DataOutputStream(client.getOutputStream());
DataInputStream dis = new DataInputStream(client.getInputStream());
boolean isRunning = true;
while (isRunning) {
String msg = console.readLine();
dos.writeUTF(msg);
dos.flush();
// 3、获取消息
msg = dis.readUTF();
System.out.println(msg);
}
// 4、释放资源
dos.close();
dis.close();
client.close();
}
}1.2 多个客户收发多条消息(不使用多线程)
- 目标：实现多个客户可以正常收发多条信息
- 出现排队问题：其他客户必须等待之前的客户退出，才能收发消息
服务器
public class MutiChat {
public static void main(String[] args) throws IOException {
System.out.println("-----Server-----");
// 1、指定端口 使用ServerSocket创建服务器
ServerSocket server = new ServerSocket(8888);
// 2、利用Socket的accept方法，监听客户端的请求。阻塞，等待连接的建立
while (true) {
Socket client = server.accept();
System.out.println("一个客户端建立了连接");
DataInputStream dis = new DataInputStream(client.getInputStream());
DataOutputStream dos = new DataOutputStream(client.getOutputStream());
boolean isRunning = true;
while (isRunning) {
// 3、接收消息
String msg = dis.readUTF();
// 4、返回消息
dos.writeUTF(msg);
dos.flush();
}
// 5、释放资源
dos.close();
dis.close();
client.close();
}
}
}1.3 多个客户收发多条消息(多线程)
- 目标：实现多个客户可以正常收发多条信息
- 出现的问题：利用Lambda太复杂，代码过多不好维护；客户端读写没有分开，必须先写后读
服务器代码
public class ThreadMutiChat {
public static void main(String[] args) throws IOException {
System.out.println("-----Server-----");
// 1、指定端口 使用ServerSocket创建服务器
ServerSocket server = new ServerSocket(8888);
// 2、利用Socket的accept方法，监听客户端的请求。阻塞，等待连接的建立
while (true) {
Socket client = server.accept();
System.out.println("一个客户端建立了连接");
// 加入多线程
new Thread(()->{
DataInputStream dis = null;
DataOutputStream dos = null;
try {
dis = new DataInputStream(client.getInputStream());
dos = new DataOutputStream(client.getOutputStream());
} catch (IOException e) {
e.printStackTrace();
}
boolean isRunning = true;
while (isRunning) {
// 3、接收消息
String msg = null;
try {
msg = dis.readUTF();
// 4、返回消息
dos.writeUTF(msg);
dos.flush();
} catch (IOException e) {
// e.printStackTrace();
isRunning = false; // 停止线程
}
}
// 5、释放资源
try {
if (null == dos) {
dos.close();
}
} catch (IOException e) {
e.printStackTrace();
}
try {
if (null == dis) {
dis.close();
}
} catch (IOException e) {
e.printStackTrace();
}
try {
if (null == client) {
client.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}).start();
}
}
}2. oop封装版
目标：封装使用多线程实现多个客户可以正常收发多条消息
- 1、线程代理 Channel，一个客户代表一个 Channel
- 2、实现方法：接收消息 - receive; 发送消息 - send; 释放资源 - release;
- 3、其中释放资源 release方法中利用工具类 Utils：实现Closeable接口、可变参数
- 好处：利用封装，是代码简洁，便于维护
服务器端
示例代码：
public class ThreadMutiChat {
public static void main(String[] args) throws IOException {
System.out.println("---服务器开始工作---");
// 1、指定端口 使用ServerSocket创建服务器
ServerSocket server = new ServerSocket(8888);
// 2、利用Socket的accept方法，监听客户端的请求。阻塞，等待连接的建立
while (true) {
Socket client = server.accept();
System.out.println("一个客户端建立了连接");
new Thread(new Channel(client)).start();
}
}
// 一个客户代表一个Channel
static class Channel implements Runnable {
private DataInputStream dis = null;
private DataOutputStream dos = null;
private Socket client;
private boolean isRunning;
public Channel(Socket client) {
this.client = client;
try {
dis = new DataInputStream(client.getInputStream());
dos = new DataOutputStream(client.getOutputStream());
isRunning = true;
} catch (IOException e) {
System.out.println("---构造时出现异常---");
release();
}
}
// 接收消息
private String receive() {
String msg = ""; // 避免空指针
try {
msg = dis.readUTF();
} catch (IOException e) {
System.out.println("---接受消息出现异常---");
release();
}
return msg;
}
// 发送消息
private void send(String msg) {
try {
dos.writeUTF(msg);
dos.flush();
} catch (IOException e) {
System.out.println("---发送消息出现异常---");
release();
}
}
// 释放资源
private void release() {
this.isRunning = false;
// 封装
Utils.close(dis, dos, client);
}
// 线程体
@Override
public void run() {
while (isRunning) {
String msg = receive();
if (!msg.equals("")) {
send(msg);
}
}
}
}
}工具类Utils：实现Closeable接口，利用可变参数，达到释放资源的作用
示例代码
public class Utils {
public static void close(Closeable... targets) {
// Closeable是IO流中接口，"..."可变参数
// IO流和Socket都实现了Closeable接口，可以直接用
for (Closeable target: targets) {
try {
// 只要是释放资源就要加入空判断
if (null != target) {
target.close();
}
}catch (Exception e) {
e.printStackTrace();
}
}
}
}客户端：启用两个线程Send和Receive实现收发信息的分离
示例代码
public class ThreadMutiClient {
public static void main(String[] args) throws IOException {
System.out.println("-----客户端开始工作-----");
Socket client = new Socket("localhost", 8888);
new Thread(new Send(client)).start();
new Thread(new Receive(client)).start();
}
}使用多线程封装客户的发送端 – Send类
实现方法：
- 1、发送消息 - send()
- 2、从控制台获取消息 - getStrFromConsole()
- 3、释放资源 - release()
- 4、线程体 - run()
示例代码
public class Send implements Runnable {
private BufferedReader console;
private DataOutputStream dos;
private Socket client;
private boolean isRunning;
public Send(Socket client) {
this.client = client;
console = new BufferedReader(new InputStreamReader(System.in)); // 对接控制台
try {
dos = new DataOutputStream(client.getOutputStream());
isRunning = true;
} catch (IOException e) {
System.out.println("---客户发送端构造时异常---");
release();
}
}
// 从控制台获取消息
private String getStrFromConsole() {
try {
return console.readLine();
} catch (IOException e) {
e.printStackTrace();
return "";
}
}
// 发送消息
private void send(String msg) {
try {
dos.writeUTF(msg);
dos.flush();
} catch (IOException e) {
System.out.println("---客户发送端发送消息异常---");
release();
}
}
@Override
public void run() {
while (isRunning) {
String msg = getStrFromConsole();
if (!msg.equals("")) {
send(msg);
}
}
}
// 释放资源
private void release() {
this.isRunning = false;
Utils.close(dos,client);
}
}使用多线程封装客户的接收端 – Receive类
实现方法：
- 1、接收消息 - send
- 2、释放资源 - release()
- 3、线程体 - run()
示例代码
public class Receive implements Runnable {
private DataInputStream dis;
private Socket client;
private boolean isRunning;
public Receive(Socket client) {
this.client = client;
try {
dis = new DataInputStream(client.getInputStream());
isRunning = true;
} catch (IOException e) {
System.out.println("---客户接收端构造时异常---");
release();
}
}
// 接收消息
private String receive() {
String msg = "";
try {
msg = dis.readUTF();
} catch (IOException e) {
System.out.println("---客户接收端接收消息异常---");
release();
}
return msg;
}
// 释放资源
private void release() {
isRunning = false;
Utils.close(dis, client);
}
@Override
public void run() {
while (isRunning) {
String msg = receive();
if (!msg.equals("")) {
System.out.println(msg);
}
}
}
}3. 群聊过渡版
目标：加入容器，实现群聊
服务器端
- 1、建立
CopyOnWriteArrayList<Channel>容器，容器中的元素是Channel客户端代理。要对元素进行修改同时遍历时，推荐使用此容器，避免出问题。 - 2、实现方法
void sendOthers(String msg)将信息发送给除自己外的其他人。
服务器端实现代码
public class Chat {
// 建立 CopyOnWriteArrayList<Channel> 容器
private static CopyOnWriteArrayList<Channel> all = new CopyOnWriteArrayList<>();
public static void main(String[] args) throws IOException {
System.out.println("---服务器开始工作---");
ServerSocket server = new ServerSocket(8888);
while (true) {
Socket client = server.accept();
System.out.println("一个客户端建立了连接");
Channel c = new Channel(client);
all.add(c); // 管理所有的成员
new Thread(c).start();
}
}
// 一个客户代表一个Channel
static class Channel implements Runnable {
private DataInputStream dis;
private DataOutputStream dos;
private Socket client;
private boolean isRunning;
private String name;
public Channel(Socket client) {
this.client = client;
try {
dis = new DataInputStream(client.getInputStream());
dos = new DataOutputStream(client.getOutputStream());
isRunning = true;
// 获取名称
this.name = receive();
// 欢迎
this.send("欢迎你的到来");
sendOthers(this.name + "加入群聊", true);
} catch (IOException e) {
System.out.println("---构造时出现问题---");
release();
}
}
// 接收消息
private String receive() {
String msg = ""; // 避免空指针
try {
msg = dis.readUTF();
} catch (IOException e) {
System.out.println("---接受消息出现问题---");
release();
}
return msg;
}
// 发送消息
private void send(String msg) {
try {
dos.writeUTF(msg);
dos.flush();
} catch (IOException e) {
System.out.println("---发送消息出现问题---");
release();
}
}
// 群聊：把自己的消息发送给其他人
private void sendOthers(String msg, boolean isSys) {
for (Channel other : all) {
if (other == this) {
continue;
}
if (!isSys) {
other.send(this.name + ": " + msg); // 群聊消息
} else {
other.send("系统消息：" + msg); // 系统消息
}
}
}
// 线程体
@Override
public void run() {
while (isRunning) {
String msg = receive();
if (!msg.equals("")) {
sendOthers(msg, false);
}
}
}
// 释放资源
private void release() {
this.isRunning = false;
// 封装
Utils.close(dis, dos, client);
// 退出
all.remove(this);
sendOthers(this.name + "离开聊天室", true);
}
}
}客户端实现代码
public class Client {
public static void main(String[] args) throws IOException {
System.out.println("-----客户端开始工作-----");
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
Socket client = new Socket("localhost", 8888);
System.out.println("请输入用户名："); // 不考虑重名
String name = br.readLine();
new Thread(new Send(client, name)).start();
new Thread(new Receive(client)).start();
}
}客户端Send类实现代码
public class Send implements Runnable {
private BufferedReader console;
private DataOutputStream dos;
private Socket client;
private boolean isRunning;
private String name;
public Send(Socket client, String name) {
this.client = client;
console = new BufferedReader(new InputStreamReader(System.in));
this.isRunning = true;
this.name = name;
try {
dos = new DataOutputStream(client.getOutputStream());
// 发送名称
send(name);
} catch (IOException e) {
System.out.println("Send类构造时异常");
release();
}
}
// 从控制台获取消息
private String getStrFromConsole() {
try {
return console.readLine();
} catch (IOException e) {
e.printStackTrace();
return "";
}
}
// 发送消息
private void send(String msg) {
try {
dos.writeUTF(msg);
dos.flush();
} catch (IOException e) {
System.out.println("---客户发送端发送消息异常---");
release();
}
}
@Override
public void run() {
while (isRunning) {
String msg = getStrFromConsole();
if (!msg.equals("")) {
send(msg);
}
}
}
// 释放资源
private void release() {
this.isRunning = false;
Utils.close(dos,client);
}
}客户端Receive类实现代码
public class Receive implements Runnable {
private DataInputStream dis;
private Socket client;
private boolean isRunning;
public Receive(Socket client) {
this.client = client;
try {
dis = new DataInputStream(client.getInputStream());
isRunning = true;
} catch (IOException e) {
System.out.println("---客户接收端构造时异常---");
release();
}
}
// 接收消息
private String receive() {
String msg = "";
try {
msg = dis.readUTF();
} catch (IOException e) {
System.out.println("---客户接收端接收消息异常---");
release();
}
return msg;
}
// 释放资源
private void release() {
isRunning = false;
Utils.close(dis, client);
}
@Override
public void run() {
while (isRunning) {
String msg = receive();
if (!msg.equals("")) {
System.out.println(msg);
}
}
}
}运行结果
4. 终极版：实现私聊
私聊形式：@XXX:
实现方法
1、boolean isPrivate = msg.startsWith("@")用于判断是否为私聊
- 利用String类中方法
-
boolean startsWith(String prefix):测试此字符串是否以指定的前缀开头
2、String targetName = msg.substring(1, index)用于判断用户名；msg = msg.substring(index+1)用于判断发送的信息
- 利用String类中方法
-
substring(int beginIndex):返回一个字符串，该字符串是此字符串的子字符串 -
substring(int beginIndex, int endIndex):返回一个字符串，该字符串是此字符串的子字符串
服务器端实现代码
public class Chat {
private static CopyOnWriteArrayList<Channel> all = new CopyOnWriteArrayList<>();
public static void main(String[] args) throws IOException {
System.out.println("---服务器开始工作---");
ServerSocket server = new ServerSocket(8888);
while (true) {
Socket client = server.accept();
System.out.println("一个客户端建立了连接");
Channel c = new Channel(client);
all.add(c); // 管理所有的成员
new Thread(c).start();
}
}
static class Channel implements Runnable {
private DataInputStream dis;
private DataOutputStream dos;
private Socket client;
private boolean isRunning;
private String name;
public Channel(Socket client) {
this.client = client;
try {
dis = new DataInputStream(client.getInputStream());
dos = new DataOutputStream(client.getOutputStream());
isRunning = true;
// 获取名称
this.name = receive();
// 欢迎
this.send("欢迎你的到来");
sendOthers(this.name + "加入群聊", true);
} catch (IOException e) {
System.out.println("---构造时出现问题---");
release();
}
}
private String receive() {
String msg = ""; // 避免空指针
try {
msg = dis.readUTF();
} catch (IOException e) {
System.out.println("---接受消息出现问题---");
release();
}
return msg;
}
private void send(String msg) {
try {
dos.writeUTF(msg);
dos.flush();
} catch (IOException e) {
System.out.println("---发送消息出现问题---");
release();
}
}
/**
* 群聊：把自己的消息发送给其他人
* 私聊：约定数据格式：@XXX:msg
* @param msg
* @param isSys
*/
private void sendOthers(String msg, boolean isSys) {
boolean isPrivate = msg.startsWith("@");
if (isPrivate) { // 私聊
int index = msg.indexOf(":"); // 第一次冒号出现的位置
// 获取目标和数据
String targetName = msg.substring(1, index);
msg = msg.substring(index+1);
for (Channel other: all) {
if (other.name.equals(targetName)) { // 目标
other.send(this.name + "对您说悄悄话: " + msg); // 群聊消息
}
}
} else {
for (Channel other : all) {
if (other == this) {
continue;
}
if (!isSys) {
other.send(this.name + ": " + msg); // 群聊消息
} else {
other.send("系统消息：" + msg); // 系统消息
}
}
}
}
@Override
public void run() {
while (isRunning) {
String msg = receive();
if (!msg.equals("")) {
sendOthers(msg, false);
}
}
}
private void release() {
this.isRunning = false;
Utils.close(dis, dos, client);
all.remove(this);
sendOthers(this.name + "离开聊天室", true);
}
}
}客户端实现代码
public class Client {
public static void main(String[] args) throws IOException {
System.out.println("-----客户端开始工作-----");
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
Socket client = new Socket("localhost", 8888);
System.out.println("请输入用户名："); // 不考虑重名
String name = br.readLine();
new Thread(new Send(client, name)).start();
new Thread(new Receive(client)).start();
}
}客户端Send类实现代码
public class Send implements Runnable {
private BufferedReader console;
private DataOutputStream dos;
private Socket client;
private boolean isRunning;
private String name;
public Send(Socket client, String name) {
this.client = client;
console = new BufferedReader(new InputStreamReader(System.in));
this.isRunning = true;
this.name = name;
try {
dos = new DataOutputStream(client.getOutputStream());
// 发送名称
send(name);
} catch (IOException e) {
System.out.println("Send类构造时异常");
release();
}
}
private String getStrFromConsole() {
try {
return console.readLine();
} catch (IOException e) {
e.printStackTrace();
return "";
}
}
private void send(String msg) {
try {
dos.writeUTF(msg);
dos.flush();
} catch (IOException e) {
System.out.println("---客户发送端发送消息异常---");
release();
}
}
@Override
public void run() {
while (isRunning) {
String msg = getStrFromConsole();
if (!msg.equals("")) {
send(msg);
}
}
}
private void release() {
this.isRunning = false;
Utils.close(dos,client);
}
}客户端Receive类实现代码
public class Receive implements Runnable {
private DataInputStream dis;
private Socket client;
private boolean isRunning;
public Receive(Socket client) {
this.client = client;
try {
dis = new DataInputStream(client.getInputStream());
isRunning = true;
} catch (IOException e) {
System.out.println("---客户接收端构造时异常---");
release();
}
}
private String receive() {
String msg = "";
try {
msg = dis.readUTF();
} catch (IOException e) {
System.out.println("---客户接收端接收消息异常---");
release();
}
return msg;
}
private void release() {
isRunning = false;
Utils.close(dis, client);
}
@Override
public void run() {
while (isRunning) {
String msg = receive();
if (!msg.equals("")) {
System.out.println(msg);
}
}
}
}Utils类实现代码
public class Utils {
public static void close(Closeable... targets) {
for (Closeable target: targets) {
try {
if (null != target) {
target.close();
}
}catch (Exception e) {
e.printStackTrace();
}
}
}
}输出结果
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