socket 实现点对点发送消息

socket：套接字，描述 ip 和 port；socket 在建立网络连接时使用；通过socket可以向网络发送请求以及应答网络请求

serverSocket：主要应用于服务器端，监听 socket 连接

具体示例代码如下：

package socket;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;

/**
* 客户端
* @author hualei
* @date Sep 3, 2017 4:26:34 PM
*
*/
public class Client {

private Socket socket;
private String alias;

public Client(){
try {
socket = new Socket("127.0.0.1", 8088);
// socket = new Socket("ip", 8088);
} catch (IOException e) {
e.printStackTrace();
}
}

public void start(){
// System.out.println("enter client ...");
Scanner scanner = null;
try {

// 接收服务端消息
ServerHandler serverHandler = new ServerHandler(socket);
Thread thread = new Thread(serverHandler);
thread.setDaemon(true);
thread.start();

OutputStream outputStream = socket.getOutputStream();
PrintWriter pw = new PrintWriter(new OutputStreamWriter(outputStream, "utf-8"), true);
// 发送单行数据 pw.println("Hello, server!");
// 发送多行数据
scanner = new Scanner(System.in);
System.out.println("请输入昵称：");
alias = scanner.nextLine();
System.out.println("你好!" + alias + ", 开始聊天吧!");
pw.println(alias + " 上线了");

while(true){
pw.println(alias + "对你说:" + scanner.nextLine());
}

} catch (IOException e) {
e.printStackTrace();
}finally{
if(socket != null){
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
scanner.close();
}
}

public static void main(String[] args) {
Client client = new Client();
client.start();
}

private class ServerHandler implements Runnable{
private Socket socket;
public ServerHandler(Socket socket){
this.socket = socket;
}
@Override
public void run() {
InputStream inputStream;
try {
inputStream = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(inputStream, "utf-8"));
while(true){
System.out.println(br.readLine());
}
} catch (IOException e) {
e.printStackTrace();
}
}

}
}

package socket;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
* 服务器端
* @author hualei
* @date Sep 3, 2017 4:26:51 PM
*
*/
public class Server {

private ServerSocket serverSocket;
// private volatile int count;
private List<PrintWriter> allOut = new ArrayList<PrintWriter>();
private ExecutorService threadPool = Executors.newFixedThreadPool(10);
private Map<String, PrintWriter> aliasOuts = new HashMap<String, PrintWriter>();

public Server(){
try {
serverSocket = new ServerSocket(8088);
} catch (IOException e) {
e.printStackTrace();
}
}

public void start(){
// System.out.println("enter server ...");
try {
// 循环监听 socket
while(true){
System.out.println("等待客户端连接...");
Socket socket = serverSocket.accept();
System.out.println("客户端连接成功");
//count ++;

// 未抽取处理类之前代码
/*System.out.println("服务端与客户端 "+count+" 建立连接");
InputStream inputStream = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(inputStream, "utf-8"));

// 接收多行数据
while(true){
System.out.println("客户端" + count + "说：" + br.readLine());
}*/
ClientHandler clientHandler = new ClientHandler(socket);
threadPool.execute(clientHandler);
}
} catch (IOException e) {
e.printStackTrace();
}
}

public static void main(String[] args) {
Server server = new Server();
server.start();
}

private class ClientHandler implements Runnable{
// private int ccount;
private Socket socket;

public ClientHandler(Socket socket /*, int count*/){
this.socket = socket;
//this.ccount = count;
}

@Override
public void run() {
// System.out.println("服务端与客户端 "+ccount+" 建立连接");
PrintWriter pw = null;
try {
// 接收客户端输出流
OutputStream outputStream = socket.getOutputStream();
pw = new PrintWriter(new OutputStreamWriter(outputStream, "utf-8"), true);
add(pw);

InputStream inputStream = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(inputStream, "utf-8"));

String content = "";
while((content = br.readLine()) != null){
if(!content.contains(":")){
aliasOuts.put(content.trim(), pw);
}

if(content.startsWith("@") && content.contains(":")){
String pwName = content.substring(content.indexOf("@"), content.indexOf(":"));
aliasOuts.get(pwName).println(content.substring(content.indexOf(":")+1));
}else{
foreach(content);
}

}

// 支持多个客户发送数据，服务器端只接收数据并展示
/*InputStream   inputStream = socket.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(inputStream, "utf-8"));
String content = "";
// 接收多行数据
while((content = br.readLine()) != null){
System.out.println("客户端" + ccount + "说：" + content);
}*/

} catch (IOException e) {
e.printStackTrace();
}finally{
remove(pw);
if(socket != null){
try {
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}

private synchronized void add(PrintWriter pw){
allOut.add(pw);
}
private synchronized void remove(PrintWriter pw){
allOut.remove(pw);
}
private synchronized void foreach(String content){
Set<Entry<String, PrintWriter>> entrySet = aliasOuts.entrySet();
Iterator<Entry<String, PrintWriter>> iterator = entrySet.iterator();

while(iterator.hasNext()){
Entry<String, PrintWriter> next = iterator.next();
String key = next.getKey();
if(!key.contains(" 上线了")){
next.getValue().println(content);
}
}
}

}