データをCSVファイルに保存し、同じファイルの読み取りと書き込みを行うことができるいくつかのメソッドを取得するゲームアプレットをプログラミングしてい.csvます。そして、どういうわけか、各メソッドがファイルへのライターストリームを開いている間にファイルをロックする必要があります。これにより、書き込みストリームを閉じるまでファイルの内容を変更できなくなりますが、読み取りアクセスのみを許可したいと思います。
出来ますか？
または、ファイルにまったくアクセスせずに実行できる場合は、それでも問題ありません。
編集：私のコンピューターはオンラインゲームアプレットを提供するサーバーになり、csvファイルは私のコンピューターにのみ存在します。与えられたものを再生するには、私のWebサイトにログインする必要があり、すべてのアカウント情報（ユーザー名、パスワード、勝ち合計、負け合計など）が私のコンピューター（サーバー）のcsvファイルに保存されます。だから私はファイルを変更するいくつかの方法があります。したがって、ファイルへの書き込み中にすべてのメソッドでロックする必要があります。理論的には、同時に数人のプレーヤーがプレイすることになります。
情報をcsvファイルに保存する理由は、javadeveloperに教育を提供し、プログラムされたのは4か月だけであるため、データベースについては2、3か月で最初に学習します。
これは学業であるため、アプレットを作成しています。私のコンピューターに接続する（単純なサーブレットとWebページを介してアプレットを提供する）唯一のユーザーは私の先生です。したがって、セキュリティ上の脅威はありません。
プレーヤーオブジェクトのコードは次のとおりです。
public class Player {
private String userName;
private String passWord;
private int currentWins;
private int currentLosses;
private int totalWins;
private int totalLosses;
private boolean isLoggedIn = false;
private String playerId;
public Player(String playerId, String userName, String passWord, int totalWins, int totalLosses) {
this.playerId = playerId;
this.userName = userName;
this.passWord = passWord;
this.totalWins = totalWins;
this.totalLosses = totalLosses;
this.currentWins = 0;
this.currentLosses = 0;
}
public Player(String userName, String passWord, int totalWins, int totalLosses) {
this.userName = userName;
this.passWord = passWord;
this.totalWins = totalWins;
this.totalLosses = totalLosses;
this.currentWins = 0;
this.currentLosses = 0;
this.playerId = UUID.randomUUID().toString();
}
public void incrementWins()
{
currentWins++;
totalWins++;
}
public void incrementLosses()
{
currentLosses++;
totalLosses++;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassword() {
return passWord;
}
public void setPassword(String passWord) {
this.passWord = passWord;
}
public boolean isLoggedIn() {
return isLoggedIn;
}
public void setLoggedIn(boolean isLoggedIn) {
this.isLoggedIn = isLoggedIn;
}
public int getTotalWins()
{
return this.totalWins;
}
public void setTotalWins(int totalWins)
{
this.totalWins = totalWins;
}
public int getTotalLoss()
{
return this.totalLosses;
}
public void setTotalLoss(int totalLoss)
{
this.totalLosses = totalLoss;
}
public int getCurrentWins()
{
return this.currentWins;
}
public void setCurrentWins(int currentWins)
{
this.currentWins = currentWins;
}
public int getCurrentLoss()
{
return this.currentLosses;
}
public void setCurrentLoss(int currentLosses)
{
this.currentLosses = currentLosses;
}
public String getPlayerId() {
return playerId;
}
public void setPlayerId(UUID playerId) {
this.playerId = playerId.toString();
}
}
ここにplayermanagerコードがあります：
public class PlayerManager {
private final File file = new File("Players.csv");
public PlayerManager() throws IOException
{
if (!file.exists())
file.createNewFile();
}
public Player getPlayer(String playerId) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(file), "UTF-8"));
String line;
while((line = reader.readLine()) != null) {
if(line.equalsIgnoreCase("PlayerID;Username;Password;Total Wins;Total Losses"))
continue;
String[] playerInfo = line.split(";");
String existingPlayerID = playerInfo[0];
String userName = playerInfo[1];
String password = playerInfo[2];
int totalWins = Integer.parseInt(playerInfo[3]);
int totalLoss = Integer.parseInt(playerInfo[4]);
if(existingPlayerID.equals(playerId)) {
reader.close();
return new Player(existingPlayerID,userName, password, totalWins, totalLoss);
}
}
reader.close();
return null;
}
public ArrayList<Player> getAllPlayers() throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(file), "utf-8"));
ArrayList<Player> players = new ArrayList<Player>();
String line;
while((line = reader.readLine()) != null)
{
if(line.equalsIgnoreCase("PlayerID;Username;Password;Total Wins;Total Losses"))
continue;
String[] playerInfo = line.split(";");
String playerID = playerInfo[0];
String userName = playerInfo[1];
String password = playerInfo[2];
int totalWins = Integer.parseInt(playerInfo[3]);
int totalLoss = Integer.parseInt(playerInfo[4]);
players.add(new Player(playerID,userName, password, totalWins, totalLoss));
}
reader.close();
return players;
}
public void savePlayer(Player player) throws IOException {
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file, true), "utf-8"));
if(file.length() == 0) {
writer.write("PlayerID;Username;Password;Total Wins;Total Losses");
writer.newLine();
writer.flush();
}
if(playerExists(player)) {
writer.close();
updatePlayer(player);
return;
}
writer.write(player.getPlayerId() + ";" + player.getUserName() + ";" + player.getPassword() + ";" +
player.getTotalWins() + ";" + player.getTotalLoss());
writer.newLine();
writer.flush();
writer.close();
}
public Player loginPlayer(String userName, String passWord) throws IOException {
for(Player p : getAllPlayers()) {
if(p.isLoggedIn())
return p;
if(p.getUserName().equals(userName) && p.getPassword().equals(passWord)) {
p.setLoggedIn(true);
return p;
}
}
return null;
}
private void updatePlayer(Player player) {
try
{
ArrayList<Player> players = getAllPlayers();
for(Player p : players) {
if(p.getPlayerId().equals(player.getPlayerId())) {
p.setUserName(player.getUserName());
p.setPassword(player.getPassword());
p.setCurrentWins(player.getCurrentWins());
p.setCurrentLoss(player.getCurrentLoss());
p.setLoggedIn(player.isLoggedIn());
p.setTotalWins(player.getTotalWins());
p.setTotalLoss(player.getTotalLoss());
break;
}
}
File tempFile = new File("Players.csv.bak");
if (!tempFile.exists())
tempFile.createNewFile();
else
{
tempFile.delete();
tempFile.createNewFile();
}
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(tempFile), "utf-8"));
if(tempFile.length() == 0) {
writer.write("PlayerID;Username;Password;Total Wins;Total Losses");
writer.newLine();
writer.flush();
}
for(Player p : players) {
writer.write(p.getPlayerId() + ";" + p.getUserName() + ";" + p.getPassword() + ";" +
p.getTotalWins() + ";" + p.getTotalLoss());
writer.newLine();
}
writer.flush();
writer.close();
this.file.delete();
tempFile.renameTo(this.file);
}
catch(Exception ex)
{
}
}
private boolean playerExists(Player player) throws IOException {
Player p = getPlayer(player.getPlayerId());
if(p != null && p.getPlayerId().equals(player.getPlayerId()))
return true;
return false;
}
}
これがサーブレットです（まだ完了していません）：
public class TickTackToeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private boolean newUser = true;
public String getLoginForm() throws IOException {
File loginForm = new File("login.html");
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(loginForm)));
StringBuilder str = new StringBuilder();
String line;
while((line = reader.readLine()) != null) {
str.append(line);
}
reader.close();
return str.toString();
}
public String displayGamePage() {
return null;
}
@Override
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html; charset=utf-8");
response.setStatus(HttpServletResponse.SC_OK);
Writer writer = response.getWriter();
String loginForm = getLoginForm();
writer.write(loginForm);
}
@Override
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html; charset=utf-8");
Writer writer = response.getWriter();
String userName = request.getParameter("username");
String passWord = request.getParameter("password");
if(userName == null || passWord == null) {
response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
writer.write("<h1>You forgot to enter username/password. Please refresh to try again.</h1>");
writer.write(getLoginForm());
return;
}
PlayerManager playerManager = new PlayerManager();
playerManager.loginPlayer(userName, passWord);
Player player = new Player(userName, passWord, 0 , 0);
if(!player.isLoggedIn()) {
response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
writer.write("<h1>Bad username or password. Please refresh to try again.</h1>");
return;
}
HttpSession session = request.getSession(true);
if(session.getAttribute(userName) == null || session.getAttribute(passWord) == null) {
session.setAttribute("username", userName);
session.setAttribute("password", passWord);
}
response.setStatus(HttpServletResponse.SC_OK);
response.sendRedirect(request.getParameter("url"));
}
public static void main(String... args) throws Exception {
ServletContextHandler context = new ServletContextHandler(ServletContextHandler.SESSIONS);
context.addServlet(TickTackToeServlet.class, "/");
Server server = new Server(8080);
server.setHandler(context);
server.start();
server.join();
}
}
これがアプレットです（まだ完了していません）：
public class TickTackToeApplet extends JApplet implements ActionListener {
private static final long serialVersionUID = 1L;
private ArrayList<JButton> buttons = new ArrayList<JButton>();
private JPanel panel = new JPanel();
private Game game;
private Player player1;
private Player player2;
private int numberOfPlacedOutChars = 0;
public TickTackToeApplet() {}
public TickTackToeApplet(int gameBoardSize, Player player1, Player player2) {
createGUI(gameBoardSize);
game = new Game(gameBoardSize);
this.player1 = player1;
this.player2 = player2;
if(!player1.isLoggedIn() && !player2.isLoggedIn()) {
try {
PlayerManager playerManager = new PlayerManager();
playerManager.loginPlayer(player1.getUserName(), player1.getPassword());
playerManager.loginPlayer(player2.getUserName(), player1.getPassword());
} catch (IllegalArgumentException e) {
JOptionPane.showMessageDialog(this, "Couldn't login player, please enter correct username & password!");
} catch (IOException e) {
JOptionPane.showMessageDialog(this, "Server error...");
e.printStackTrace();
}
}
}
// public void init() {
// new TickTackToeApplet(4, "Henrik", "temp123");
// }
public void CreateButtons(int gameBoardSize)
{
for(int x=0; x<gameBoardSize; x++)
{
for(int y=0; y<gameBoardSize; y++)
{
JButton btn = new JButton("");
btn.setFont(new Font("Tahoma", Font.PLAIN, 32));
btn.setName(x + ";" + y);
btn.addActionListener(this);
buttons.add(btn);
}
}
}
public void PlaceOutButtons()
{
for(JButton btn : buttons)
panel.add(btn);
}
public void createGUI(int gameBoardSize) {
panel.setSize(gameBoardSize*25, gameBoardSize*25);
panel.setBackground(Color.BLACK);
getContentPane().add(panel, BorderLayout.CENTER);
panel.setLayout(new GridLayout(gameBoardSize, gameBoardSize));
CreateButtons(gameBoardSize);
PlaceOutButtons();
}
@Override
public void actionPerformed(ActionEvent e) {
JButton buttonClicked = (JButton)e.getSource();
String coordinates = buttonClicked.getName();
String[] strArr = coordinates.split(";");
int x = Integer.parseInt(strArr[0]);
int y = Integer.parseInt(strArr[1]);
if (numberOfPlacedOutChars % 2 == 0) {
game.placeChar('X', x, y);
buttonClicked.setText("X");
buttonClicked.setEnabled(false);
}
else {
game.placeChar('O', x, y);
buttonClicked.setText("O");
buttonClicked.setEnabled(false);
}
numberOfPlacedOutChars++;
boolean win = game.checkWin();
if(win == true) {
player1.incrementWins();
try {
PlayerManager playerManager = new PlayerManager();
playerManager.savePlayer(player1);
} catch (IllegalArgumentException | IOException e1) {
JOptionPane.showMessageDialog(this, "Couldn't update player info!");
}
for(JButton btn : buttons) {
btn.setEnabled(false);
}
int choice = JOptionPane.showConfirmDialog(this, "Winner is: " + player1.getUserName() + ", play again?", "WE GOT A WINNER", JOptionPane.YES_NO_OPTION);
if(choice == 0) {
for(JButton btn : buttons) {
btn.setEnabled(true);
btn.setText("");
}
}
}
}
}