我正在尝试制作客户端 - 服务器应用程序。它是关于图书馆的，每个新客户都必须看到当前的图书库存。我不知道，当新客户启动时服务器如何发送实际库存。在我的应用程序中，新客户始终可以查看最初的书籍库存。有什么建议？提前致谢。这是我的代码：
服务器
package Server;
import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.JOptionPane;
class Readers {
private ArrayList<PrintWriter> pW;
public Readers() {
pW = new ArrayList<PrintWriter>(10);
}
public synchronized void addR(PrintWriter p) {
pW.add(p);
}
public synchronized void rmvR(PrintWriter p) {
pW.remove(p);
}
public synchronized void sendR(String s) {
Iterator<PrintWriter> itr = pW.iterator();
while (itr.hasNext()) {
PrintWriter p = (PrintWriter) itr.next();
p.println(s);
}
}
}
class ServeOneReader extends Thread {
private Socket socket;
private BufferedReader in;
private PrintWriter out;
public static int available1=3;//initial stock of book 1
public static int available2=3;//initial stock of book 2
String book1 = "The cat in the had";
String book2 = "Harry Potter";
Readers rd;
public ServeOneReader(Socket s, Readers rd) throws IOException {
socket = s;
this.rd = rd;
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
// Enable auto-flush:
out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
socket.getOutputStream())), true);
// If any of the above calls throw an
// exception, the caller is responsible for
// closing the socket. Otherwise the thread
// will close it.
rd.addR(out);
start(); // Calls run()
}
public void run() {
try {
while (true) {
String str = in.readLine();//client sends suffix "borrowed" or "returned" after book's name
if (str.equals(book1 + "borrow")) {//check if the book was borrowed
available1--;
System.out.println("Book " + str + " Stock: " + available1);
String answer = book1 + " Stock: " + available1;
rd.sendR(answer);
out.println(book1);//Server sends back the book's name to the client to identify which stock decreases
out.println(available1);//stock of book 1
}
if (str.equals(book2 + "borrow")) {//check if the book was borrowed
available2--;
System.out.println("Book " + str + " Stock: " + available2);
String answer = book2 + " Stock: " + available2;
rd.sendR(answer);
out.println(book2);
out.println(available2);
}
if (str.equals(book1 + "returned")) {//check if the book was returned
available1++;
System.out.println("Book " + str + " Stock: " + available1);
String answer = book1 + " Stock: " + available1;
rd.sendR(answer);
out.println(book1);
out.println(available1);
}
if (str.equals(book2 + "returned")) {//check if the book was returned
available2++;
System.out.println("Book " + str + " Stock: " + available2);
String answer = book2 + " Stock: " + available2;
rd.sendR(answer);
out.println(book2);
out.println(available2);
}
}
} catch (IOException e) {
} finally {
try {
socket.close();
} catch (IOException e) {
}
}
}
}
enter code here
public class LibrarySrv {
static final int PORT = 9090;
public static void main(String[] args) throws IOException {
ServerSocket s = new ServerSocket(PORT);
System.out.println("Server Started");
Readers rd = new Readers();
try {
while (true) {
// Blocks until a connection occurs:
Socket socket = s.accept();
try {
new ServeOneReader(socket, rd);
} catch (IOException e) {
// If it fails, close the socket,
// otherwise the thread will close it:
socket.close();
}
}
} finally {
s.close();
}
}
}
客户端
package Server;
import java.net.*;
import java.awt.*;
import java.io.*;
import java.awt.event.*;
import javax.swing.*;
import MyPackige.Books;
public class Reader {
BufferedReader in;
PrintWriter out;
InetAddress addr;
Socket socket;
Gui g;
Reader(JFrame frame) {
g = new Gui(frame);
}
class Gui {
JPanel panelChB, panelText, panelStock;
private JLabel title, bookTitle, bookTitle1, stock1, stock2;
private JButton getBook, returnBook;
private JCheckBox ch1, ch2;
boolean haveBook1 = false;
boolean haveBook2 = false;
String book1 = "The cat in the had";
String book2 = "Harry Potter";
String stockFB=Integer.toString(ServeOneReader.available1);//Stock first book and Stock second book must be equal to the current variable availabel1/2 in Server but it is always 3
String stockSB =Integer.toString(ServeOneReader.available2);
private void updateStockDisplay() { // update the frame after every stock changes
stock1.setText("Stock: " + stockFB);
stock2.setText("Stock: " + stockSB);
}
Gui(JFrame frame) {
frame.setSize(400, 150);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setTitle("Books");
frame.setResizable(false);
frame.setLayout(new BorderLayout());
frame.setVisible(true);
panelChB = new JPanel();
panelChB.setLayout(new BoxLayout(panelChB, BoxLayout.Y_AXIS));
ch1 = new JCheckBox();
ch2 = new JCheckBox();
getBook = new JButton("Borrow");
getBook.addActionListener(new SrvL());
(new Rcv()).start();
returnBook = new JButton("Return");
returnBook.addActionListener(new SrvL1());
panelChB.add(ch1);
panelChB.add(ch2);
panelChB.add(getBook);
panelChB.add(returnBook);
panelText = new JPanel();
panelText.setLayout(new BoxLayout(panelText, BoxLayout.Y_AXIS));
bookTitle = new JLabel("The cat in the had");
bookTitle1 = new JLabel("Harry Potter");
panelText.add(bookTitle);
panelText.add(bookTitle1);
panelStock = new JPanel();
panelStock.setLayout(new BoxLayout(panelStock, BoxLayout.Y_AXIS));
stock1 = new JLabel();
stock2 = new JLabel();
updateStockDisplay();
panelStock.add(stock1);
panelStock.add(stock2);
frame.add(panelChB, BorderLayout.WEST);
frame.add(panelText, BorderLayout.CENTER);
frame.add(panelStock, BorderLayout.EAST);
}
class SrvL implements ActionListener {
public void actionPerformed(ActionEvent e) {
if (ch1.isSelected() || ch2.isSelected()) { //check if a book is selected
if (ch1.isSelected() && haveBook1==false) {// check if book 1 is selected
String infoMessage = "Book \"" + book1 + "\" borrowed";
JOptionPane.showMessageDialog(null, infoMessage,
"Message: ", JOptionPane.INFORMATION_MESSAGE);
out.println(book1 + "borrow");//send to the server suffix "borrow" after book's name to indicate the stock has to be decrease
haveBook1 = true;//the client can't borrow the same book anymore
}
if (ch2.isSelected() && haveBook2==false) {
String infoMessage = "Book \"" + book2 + " \" borrowed";
JOptionPane.showMessageDialog(null, infoMessage,
"Message: ", JOptionPane.INFORMATION_MESSAGE);
out.println(book2 + "borrow");
haveBook2 = true;
}
} else {
String infoMessage = "No book selected";
JOptionPane.showMessageDialog(null, infoMessage,
"Message: ", JOptionPane.INFORMATION_MESSAGE);
}
}
}
class SrvL1 implements ActionListener {
public void actionPerformed(ActionEvent e) {
if (ch1.isSelected() || ch2.isSelected()) {
if (ch1.isSelected() && haveBook1==true) {
String infoMessage = "Book \"" + book1
+ " \" returned";
JOptionPane.showMessageDialog(null, infoMessage,
"Message: ", JOptionPane.INFORMATION_MESSAGE);
out.println(book1 + "returned");
haveBook1 = false;
}
if (ch2.isSelected() && haveBook2==true) {
String infoMessage = "Book \"" + book2
+ " \" returned";
JOptionPane.showMessageDialog(null, infoMessage,
"Message: ", JOptionPane.INFORMATION_MESSAGE);
out.println(book2 + "returned");
haveBook2 = false;
}
} else {
String infoMessage = "No book selected";
JOptionPane.showMessageDialog(null, infoMessage,
"Message: ", JOptionPane.INFORMATION_MESSAGE);
}
}
}
//Receive data from the server
class Rcv extends Thread {
public void run() {
for (;;) {
try {
sleep(400);
} catch (InterruptedException e) {
}
try {
String infoMessage = in.readLine();
JOptionPane.showMessageDialog(null, infoMessage,
"Message: ", JOptionPane.INFORMATION_MESSAGE);
String stock=in.readLine();//Server sends book's name and current stock
if(stock.contains(book1)){//check which book it comes
stockFB = in.readLine();//Server sends only current stock
updateStockDisplay();
}
if(stock.contains(book2)){
stockSB = in.readLine();
updateStockDisplay();
}
} catch (IOException e1) {
break;
}
}
System.out.println(" closing reading thread...");
try {
socket.close();
} catch (Exception expt) {
System.out.println(expt);
}
System.exit(0);
}
}
}
public void init() throws IOException {
try {
String server = "192.0.0.0";
InetAddress addr = InetAddress.getByName(server);
System.out.println("addr = " + addr);
socket = new Socket(addr, LibrarySrv.PORT);
System.out.println("socket = " + socket);
// BufferedReader sin = new BufferedReader(
// new InputStreamReader(System.in));
in = new BufferedReader(new InputStreamReader(
socket.getInputStream()));
// Output is automatically flushed
// by PrintWriter:
out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
socket.getOutputStream())), true);
} catch (Exception e) {
System.out.println("exception: " + e);
System.out.println("closing...");
socket.close();
}
}
public static void main(String[] args) throws IOException {
JFrame frame = new JFrame();
frame.setVisible(true);
Reader rd = new Reader(frame);
rd.init();
}
}
答案 0 :(得分：0)
当您启动客户端时，向服务器发送消息以获取Book Stock上的当前信息。
在服务器中，您已经在侦听不同类型的消息，让它再处理一条消息 - GetStockInfo。然后，您可以将存储在服务器上的书籍名称发送给客户端。
这可以解决您的问题。
答案 1 :(得分：0)
使用需要在客户端和服务器之间发送的操作代码，然后再传回任何数据。类推。
例如：
等...
在客户端和服务器之间设置通信协议。
检查新添加的客户的库存数据需要遵循的步骤：
CLIENT_ADDED。每种类型的操作代码都遵循相同的步骤。
根据您的要求，您可以在代码中进行修改：
<强> ServerOneReader：
public void run() {
try {
while (true) {
String str = in.readLine();// client sends suffix "borrowed" or "returned" after
// book's name
if(str.equals("client_added")){
String answer1 = book1 + " Stock: " + available1;
rd.sendR(answer);
String answer2 = book2 + " Stock: " + available2;
rd.sendR(answer2);
}
if (str.equals(book1 + "borrow")) {// check if the book was borrowed
available1--;
...