Socket简称套接字，用于实现网络上客户和服务器之间的连接，也就是说网络上两个或两个以上通信的进程间总有一个连接，这个连接的端点称为套接字，套接字是比较低层次上的通信，不同操作系统对Scoket有不同的支持方式，不同的开发工具，对Socket的实现也均不相同，而且Scoket在TCP与UDP两大协议族系中有各自的工作方式。
网络中互相通信的两端，其中提供服务的一端叫服务器，而请求服务的一端叫客户机。Scoket通常用来实现Client/Server设计过程，所谓Client/Server是指通信双方一方作为服务器（Server）等待客户（Client）提出请求并予以响应。客户则在需要服务时向服务器提出申请。服务器监听网络端口，一旦有客户请求，就会启动一个服务进程来响应客户，同时继续监听服务端口，使其他客户的请求也能及时得到处理。一般连接过程是：Server端监听某个端口（port）是否有连接请求，Client端向Server端发出连接（Connect）请求，Server端向Client端发出接受（Accept）消息，一个连接就建立起来了。Server端和Client端都可以通过Send，Write等方法与对方通信。
在java中实现Scoket通讯：
首先在服务器端创建ServerSocket类对象，来创建服务器对象，其格式如下：
ServerSocket 服务器对象名 = new ServerSocket（端口号）；
通过调用accept（）方法来创建一个Scoket对象，其格式如下：
Scoket 对象名 = 服务器对象名.accept（）；
服务器端可以用利用这个Scoket对象与客户端进行通讯，通过Scoket对象拿到输入输出流。在所有通信结束后，关闭输入输出流，再关闭Scoket。
服务器和客户端属于两个不同项目
以下是服务器类代码的实现：（MyServer类和ServerThread类在同一个项目包中）
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
/**
* 服务器类
*
*/
public class MyServer {
//队列保存对象
public static ArrayList<ServerThread> list = new ArrayList<ServerThread>();
//Map定义用户名密码集合
public static Map<String,String> userInfoMap = new HashMap<String,String>();
public static void main(String[] args) {
//初始化用户登录信息
for(int i=0;i<5;i++){
userInfoMap.put("user"+i, "pwd"+i);
}
MyServer ms = new MyServer();
ms.initServer(9090);
}
public void initServer(int port){
boolean flag = true;
try {
//创建服务器套接字对象，并给定端口号
ServerSocket server = new ServerSocket(port);
System.out.println("服务器创建成功，端口号为"+port+"，等待客户机连接");
while(flag){
//等待客户机连接服务器
Socket socket = server.accept();
System.out.println("客户机连接成功!");
//创建服务器线程对象
ServerThread st = new ServerThread(socket);
list.add(st);
st.start();
}
server.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.Socket;
import com.huaxin.client.CommonNet;
/**
* 服务器线程对象
*/
public class ServerThread extends Thread{
public Socket socket;
public InputStream ins;
public OutputStream ous;
public ServerThread(Socket socket){
this.socket = socket;
}
public void run() {
try{
//拿到输入输出流
ins= socket.getInputStream();
ous =socket.getOutputStream();
//把字节流封装为字符流
InputStreamReader isReader = new InputStreamReader(ins);
BufferedReader read = new BufferedReader(isReader);
//发送消息给客户机
String msg = "欢迎连接服务器!\r\n";
CommonNet.sendMsg(ous,msg);
String user_msg = "请输入用户名：\r\n";
CommonNet.sendMsg(ous,user_msg);
//接收客户端发送过来的用户名
String username = read.readLine();
String user_pwd = "请输入密码：\r\n";
CommonNet.sendMsg(ous,user_pwd);
//接收客户端发送过来的用户名
String password = read.readLine();
//验证是否登录成功
if(MyServer.userInfoMap.containsKey(username)){
String pwd = MyServer.userInfoMap.get(username);
if(pwd.equals(password)){
CommonNet.sendMsg(ous,"true\r\n");
//循环读取消息
String value = "";
while(!"bye".equals(value)){
value = CommonNet.readMsg(ins);
System.out.println("客户机说："+value);
//把读取到的消息转发到其他客户
CommonNet.castMsg(this,username+"说："+value);
}
}else{
CommonNet.sendMsg(ous,"false\r\n");
}
}else{
CommonNet.sendMsg(ous,"false\r\n");
}
//关闭相关链接
ous.flush();
ous.close();
ins.close();
socket.close();
}catch(Exception e){
e.printStackTrace();
}
}
}
下面是客户端类代码的实现：（MyClient类和CommonNet类属于同一项目的包中）
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Scanner;
public class MyClient {
public static void main(String[] args) {
//连接服务器
try {
Socket client = new Socket("localhost",5656);
InputStream ins = client.getInputStream();
OutputStream ous = client.getOutputStream();
//把字节流封装为字符流
InputStreamReader isReader = new InputStreamReader(ins);
BufferedReader read = new BufferedReader(isReader);
//读取欢迎
String value = read.readLine();
System.out.println(value);
//读取请输入用户名
String value1 = read.readLine();
System.out.println(value1);
//发送消息
Scanner scan = new Scanner(System.in);
String scan_value = scan.nextLine();
CommonNet.sendMsg(ous, scan_value+"\r\n");
value1 = read.readLine();
System.out.println(value1);
scan_value = scan.nextLine();
CommonNet.sendMsg(ous, scan_value+"\r\n");
if("true".equals(read.readLine())){
System.out.println("登录成功");
}else{
System.out.println("登录失败");
}
ins.close();
ous.close();
client.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}
import java.io.InputStream;
import java.io.OutputStream;
import com.huaxin.server.MyServer;
import com.huaxin.server.ServerThread;
public class CommonNet {
/**
*
* @param ous
* @param msg
* @throws Exception
*/
public static void sendMsg(OutputStream ous,String msg) throws Exception{
byte[] bytes = msg.getBytes();
ous.write(bytes);
}
/**
*
* @param ins
* @return
* @throws Exception
*/
public static String readMsg(InputStream ins) throws Exception{
//接收客户机发送的消息
int readByte = ins.read();
String value = "";
StringBuffer sb = new StringBuffer();
//循环读取字节
while(readByte!=13){
sb.append((char)readByte);
readByte = ins.read();
}
//String.trim()去除字符串前后空格回车
value = sb.toString().trim();
return value;
}
/**
*
* @param st
* @param value
* @throws Exception
*/
public static void castMsg(ServerThread st,String value) throws Exception{
for(int i=0;i<MyServer.list.size();i++){
OutputStream list_ous = MyServer.list.get(i).ous;
if(MyServer.list.get(i)!=st){
sendMsg(list_ous,value+"\r\n");
}
}
}
}