我只是尝试使用java（NetBeans），我虽然是基于快速文本的冒险游戏。我试图让它在两个文本文件中检查您的用户名和密码＆＃34; users.txt＆＃34;和＆＃34; passwords.txt＆＃34;我正在关注编程洞穴
的指南以下是导入
import java.io.*;
import javax.swing.JFrame;
这是错误的地方，
private void loginActionPerformed(java.awt.event.ActionEvent evt) {
String usernametxt = "users.txt";
String passwordtxt = "passwords.txt";
String user = null;
String pass = null;
try {
// file reader for username \\
FileReader fileReader = new FileReader(usernametxt);
// file reader for password \\
FileReader fr = new FileReader(passwordtxt);
// buffered reader for username \\
BufferedReader bufferedReader = new BufferedReader(fileReader);
// buffered reader for password \\
BufferedReader br = new BufferedReader(fr);
// check for if user doesn't equal null \\
while((user = bufferedReader.readLine()) != null){
// if username equals first line of username.txt \\
if (username.getText().equalsIgnoreCase(user)){
// check for if pass doesn't equal null \\
while((pass = br.readLine()) != null){
// if password equals first line of passwords.txt \\
if (password.getPassword().equals(pass)){
// if password = pass than it will exit \\
System.exit(1);
}
// else continue \\
else{
continue;
}
}
}
}
bufferedReader.close();
br.close();
}
catch(FileNotFoundException ex){
System.out.println("Unable to open file ");
}
catch(IOException ex){
System.out.println("Error reading file");
}
}
以下是文本文件
users.txt
matthew
passwords.txt
matt
此处提供完整代码 http://textuploader.com/57urs
最新代码 http://textuploader.com/577qk
随时在这里问我问题。
提前感谢您的帮助！
最新代码
private void loginActionPerformed(java.awt.event.ActionEvent evt) {
String usernames = username.getText();
String passwords = password.toString();
boolean signedin = false;
String usernametxt = "users.txt";
String passwordtxt = "passwords.txt";
String user = null;
String pass = null;
try {
FileReader fr1 = new FileReader(usernametxt);
FileReader fr2 = new FileReader(passwordtxt);
BufferedReader br1 = new BufferedReader(fr1);
BufferedReader br2 = new BufferedReader(fr2);
System.out.println("Username: "+br1.readLine());
System.out.println("Password: "+br2.readLine());
//循环未运行（不是if语句错误\
while ((user = br1.readLine()) != null){
// checks if username is not equal to usernames.txt \\
if (user.equalsIgnoreCase(usernames)){
System.out.println("while loop running, username (right)");
break;
}
else{
System.out.println("while loop running, username (wrong)");
}
}
br1.close();
while ((pass = br2.readLine())!= null){
if (pass.equalsIgnoreCase(passwords)){
signedin = true;
System.out.println("While loop running, password (right)");
break;
}
else{
System.out.println("While loop running, password (wrong)
}
}
br2.close();
//注释掉if语句，因为我不想在测试时关闭\
// if (signedin){
// System.out.println("SIGNEDIN = TRUE");
// new error1().setVisible(true);
// this.dispose();
// }
// if (!signedin){
// System.out.println("SIGNEDIN = FALSE");
// System.exit(1);
// }
}
catch(FileNotFoundException ex){
System.out.println("Unable to open file ");
}
catch(IOException ex){
System.out.println("Error reading file");
}
}
新问题
while循环不运行，这在未打印时确认＆＃34;循环运行时，User / Pass＆＃34;，这不是if / then语句错误，因为我添加了如果用户名是对或错，则打印else语句。请帮忙，谢谢马修。
答案 0 :(得分：0)
如果我理解正确的话：
两个文件：
我们希望：
检查代码，while((user = bufferedReader.readLine()) != null)很好地完成了第一部分。我们想继续阅读整个文件，试图找到我们的用户，对吗？
但嵌套的时候看起来有点可疑。我们只需要检查给定用户的SINGLE密码，对吧？ RIGHT？
深入研究代码，我们看到：
if (password.getPassword().equals(pass)) {
// if password = pass than it will exit
System.exit(1);
} // plus Lots of code...
喂！我不认为System.exit做你正在寻找的事情！
System.exit将退出该程序，返回DOS或这些天酷孩子正在使用的任何东西。它返回的整数称为错误代码，可用于将信息反馈给启动程序的终端/ shell。
您最有可能寻找的关键字是 break ：这将退出给定的循环播放器，不会出现任何问题。
让我们做一些休息/继续mashup！假设我们在生活中获胜＆＃34;如果密码确实正确：
boolean winAtLife = false;
while((user = bufferedReader.readLine()) != null){
String candidatePassword = br.readLine();
if (candidatePassword == null) {
// So the password file is shorter than the userfile?
// We probably want to log or alert the poor DevOp guys.
// throwing an exception seems like the right thing to do here!
break;
}
if (!user.equalsIgnoreCase(username.getText())) {
// These are not the droid we're looking for, Better luck next line!
continue;
// Also notice that, since we KNOW that user can't be null,
// we're using the force to save ourselves from dreaded NullPointerExceptions!
}
if (!candidatePassword.equals(password.getPassword())) {
// Hmmm, wrong password, I guess?
// Not sure what do do next, but we DO NOT need to keep looping
// since we've found our droid/user/whatever.
// So let's break and save some EC2 Cycles.
break;
}
// If we ever reach here, we got ourselves a winner!
pass = candidatePassword
winAtLife = true;
}
所以在这里，我们选择两个，现在作为一种方法：
public boolean checkCredentials(String username, String password) throws IOException {
// these two are begging to be constants or inlined.
final String usernametxt = "users.txt";
final String passwordtxt = "passwords.txt";
if (username == null || password == null) {
// You probably don't want this in production code.
// Exceptions are your best friends when something unexpected occurs.
return false;
}
try (final Reader fileReader = new FileReader(usernametxt);
final Reader passwordReader = new FileReader(passwordtxt)) {
Scanner userScanner = new Scanner(fileReader);
Scanner passwordScanner = new Scanner(passwordReader);
while(userScanner.hasNext()) {
final String user = userScanner.next();
if (!passwordScanner.hasNext()) {
// So the password file is shorter than the userfile?
// We probably want to log or alert the poor DevOp guys.
// throwing an exception seems like the right thing to do here!
return false;
}
final String candidatePassword = passwordScanner.next();
if (!user.equalsIgnoreCase(username)) {
// This is not the droid we're looking for
// Also notice that, since we KNOW that user can't be null,
// we're using the force to save ourselves
// from dreaded NullPointerExceptions!
continue;
}
if (!candidatePassword.equals(password)) {
// Hmmm, wrong password, I guess?
// Not sure what do do next, but we DO NOT need to keep looping
// So let's return early and save some EC2 Cycles.
return false;
}
// If we ever reach here, we got ourselves a winner!
return true;
}
} // yay for autocloseable
return false;
}