我正在为飞机的问题（用于学校）创建服务器和客户端。
问题是我如何使用带有Java套接字的列表，以便客户端能够选择飞机上的某个特定座位（如果有）。
通过使用案例，客户可以查看哪些座位可用，但是我不确定是否有更好的方法来解决这个问题
// It contains two classes : Server and ClientHandler
// Save file as Server.java
import java.io.*;
import java.text.*;
import java.util.*;
import java.net.*;
// Server class
public class Server
{
public static void main(String[] args) throws IOException
{
// server is listening on port 5056
ServerSocket ss = new ServerSocket(5056);
// running infinite loop for getting
// client request
while (true)
{
Socket s = null;
try
{
// socket object to receive incoming client requests
s = ss.accept();
System.out.println("A new client is connected : " + s);
// obtaining input and out streams
DataInputStream dis = new DataInputStream(s.getInputStream());
DataOutputStream dos = new DataOutputStream(s.getOutputStream());
System.out.println("Assigning new thread for this client");
// create a new thread object
Thread t = new ClientHandler(s, dis, dos);
// Invoking the start() method
t.start();
}
catch (Exception e){
s.close();
e.printStackTrace();
}
}
}
}
// ClientHandler class
class ClientHandler extends Thread
{
DateFormat fordate = new SimpleDateFormat("yyyy/MM/dd");
DateFormat fortime = new SimpleDateFormat("hh:mm:ss");
final DataInputStream dis;
final DataOutputStream dos;
final Socket s;
// Constructor
public ClientHandler(Socket s, DataInputStream dis, DataOutputStream dos)
{
this.s = s;
this.dis = dis;
this.dos = dos;
}
@Override
public void run()
{
String received;
String toreturn;
while (true)
{
try {
// Ask user what he wants
dos.writeUTF("What do you want?[Date | Time]..\n"+
"Type Exit to terminate connection.");
// receive the answer from client
received = dis.readUTF();
if(received.equals("Exit"))
{
System.out.println("Client " + this.s + " sends exit...");
System.out.println("Closing this connection.");
this.s.close();
System.out.println("Connection closed");
break;
}
// creating Date object
Date date = new Date();
// write on output stream based on the
// answer from the client
switch (received) {
case "Date" :
toreturn = fordate.format(date);
dos.writeUTF(toreturn);
break;
case "Time" :
toreturn = fortime.format(date);
dos.writeUTF(toreturn);
break;
case "Seat" :
toreturn=
default:
dos.writeUTF("Invalid input");
break;
}
} catch (IOException e) {
e.printStackTrace();
}
}
try
{
// closing resources
this.dis.close();
this.dos.close();
}catch(IOException e){
e.printStackTrace();
}
}
}
答案 0 :(得分：0)
如果要将列表从服务器发送到客户端，可以使用Java对象序列化，如下所示：
您可以使用这样的类来存储仍然可用的座位。重要的部分是该类必须实现接口Serializable。
package serializeList;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
public class Seats implements Serializable {
//recommended for serializable classes (but not needed)
private static final long serialVersionUID = -2916554242169592691L;
private List<String> availableSeats;
public Seats(List<String> availableSeats) {
this.availableSeats = availableSeats;
}
public static Seats findAvailableSeats() {
List<String> seats = new ArrayList<String>();
//TODO find the avialable seats somehow...
return new Seats(seats);
}
public List<String> getAvailableSeats() {
return availableSeats;
}
public void setAvailableSeats(List<String> availableSeats) {
this.availableSeats = availableSeats;
}
}
然后，您可以像这样更改服务器代码：
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.net.Socket;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
// ClientHandler class
class ClientHandler extends Thread {
DateFormat fordate = new SimpleDateFormat("yyyy/MM/dd");
DateFormat fortime = new SimpleDateFormat("hh:mm:ss");
final DataInputStream dis;
final DataOutputStream dos;
final Socket s;
ObjectOutputStream oos;
// Constructor
public ClientHandler(Socket s, DataInputStream dis, DataOutputStream dos) {
this.s = s;
this.dis = dis;
this.dos = dos;
try {
this.oos = new ObjectOutputStream(dos);
}
catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void run() {
String received;
String toreturn;
while (true) {
try {
// Ask user what he wants
dos.writeUTF("What do you want?[Date | Time]..\n" + "Type Exit to terminate connection.");
// receive the answer from client
received = dis.readUTF();
if (received.equals("Exit")) {
System.out.println("Client " + this.s + " sends exit...");
System.out.println("Closing this connection.");
this.s.close();
System.out.println("Connection closed");
break;
}
// creating Date object
Date date = new Date();
// write on output stream based on the
// answer from the client
switch (received) {
case "Date":
toreturn = fordate.format(date);
dos.writeUTF(toreturn);
break;
case "Time":
toreturn = fortime.format(date);
dos.writeUTF(toreturn);
break;
case "Seat":
Seats seatsToReturn = Seats.findAvailableSeats();
oos.writeObject(seatsToReturn);
default:
dos.writeUTF("Invalid input");
break;
}
}
catch (IOException e) {
e.printStackTrace();
}
}
try {
// closing resources
this.dis.close();
this.dos.close();
}
catch (IOException e) {
e.printStackTrace();
}
}
}
当然，您必须在客户端添加一些更改。也许像这样：
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
public class SeatClient {
private DataOutputStream dos;
private ObjectInputStream ois;
public SeatClient() {
//TODO create the object input stream (from your socket streams)
//TODO also create the data output stream to send to the server
}
public void getSeats() {
String toSend = "Seat";
try {
dos.writeUTF(toSend);//to let the server know you want to know the available seats
Seats seats = (Seats) ois.readObject();//assuming that the next received object is from type Seats
//TODO do something useful with the seats...
}
catch (IOException e) {
e.printStackTrace();
}
catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}
因此，现在您可以将可用席位列为客户列表。如果您不希望列表包含字符串，那么只要通用类型（替换字符串的类型）还实现了Serializable（许多诸如List，String和许多als这样的类），它也是可能的。