有两个文件,一个是userData.txt,另一个是gameData.txt。在我的程序中,我为用户提供了两个选项。登录并注册。如果用户单击“注册”选项,那么我会询问他们想要保留的 ID 和密码并将其存储在 userData.txt 中。然后,我运行一个命令,生成一个随机字符串,该字符串将与用户的凭据一起存储在 userData.txt 和 gameData.txt 中。在gameData.txt中写入唯一 token 后,我将默认分配0个硬币。它将如下所示:
Akshit,乔希,687fd7d1-b2a9-4e4a-bc35-a64ae8a25f5b(在 userData.txt 中)
687fd7d1-b2a9-4e4a-bc35-a64ae8a25f5b,0(在gameData.txt中)
现在,如果用户单击登录选项,程序就会验证 userData.txt 中的数据。它还读取凭据后的唯一 token ,然后将其存储到名为 uniUserID 的变量中。
现在是我陷入困境的部分了。我将此 uniUserID 与 gameData.txt 文件中的数据进行比较。 Scanner 逐行读取 gameData.txt 并将 uniUserID 与其进行比较。我想要的是,如果它找到ID,那么它应该读取它后面的硬币(即0)并将其存储到名为硬币的变量中。但它向我抛出了一个类似“NoSuchElementException”的错误
这是代码:
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.util.Scanner;
import java.util.UUID;
public class Verification
{
static File credentials = new File ("C:\\Users\\user\\IdeaProjects\\Economic Bot\\out\\userData.txt"); //Clarifying filepath
static String uniUserID = " ";
static File gameData = new File ("C:\\Users\\user\\IdeaProjects\\Economic Bot\\out\\gameData.txt");
public boolean Verify (String ID,String Pass)
{
String tempName = " "; //the data read from the .txt file would be stored in these temporary variables
String tempPass = " ";
boolean found = false;//declaring some boolean variables so that the do while and if else statements work smoothly
boolean verified = false;
try //Try and catch block is initialized in case the file is not found
{
do
{
Scanner s2 = new Scanner(credentials); //Reading the .txt file
s2.useDelimiter("[,\n]");// The file reader will stop once it encounters any of the following delimiters
while (s2.hasNext() && !found)
{
tempName = s2.next(); //assigning the data read from the file to these variables
tempPass = s2.next();
uniUserID= s2.next();
if (tempName.trim().equals(ID) && tempPass.trim().equals(Pass))//comparing the data read from the file and the data entered by the user
{
verified = true;
found = true;
}
}
}
while (found = false);
}
catch (Exception ex)
{
System.out.println("Error");
}
return verified;
}
public void Write (String newUser, String newPass) {
String uniID = " ";
try {// try catch is used in case the file is not found
uniID = UUID.randomUUID().toString();
FileWriter writer = new FileWriter(credentials, true);// initializing the FileWriter, to make sure that it doesn't overwrite true is used so that it appends
BufferedWriter buffwrite = new BufferedWriter(writer); // creating buffered writer object
buffwrite.write("\n"); // Writing the new user's credentials into the .txt file
buffwrite.write(newUser);
buffwrite.write(",");
buffwrite.write(newPass);
buffwrite.write(",");
buffwrite.write(uniID);
buffwrite.close();
} catch (Exception ex) {
System.out.println("Error");
}
try
{
FileWriter writer2 = new FileWriter(gameData, true);
BufferedWriter buffwrite2 = new BufferedWriter(writer2);
buffwrite2.write("\n");
buffwrite2.write(uniID);
buffwrite2.write(",");
buffwrite2.write("0");
buffwrite2.close();
}
catch(Exception ex)
{
System.out.println("Error");
}
}
public static void Game(String uniqueID) throws FileNotFoundException
{
Scanner s3 = new Scanner (gameData);
String waste = " ";
String coins = " ";
while (s3.hasNextLine())
{
String fileLine = s3.nextLine();
if(fileLine.contains(uniUserID))
{
s3.useDelimiter(("[\n]"));
s3.skip(uniUserID);
coins = s3.next();
}
}
System.out.println(coins);
}
public static void main(String[] args) throws FileNotFoundException {
Verification obj = new Verification();
Scanner s1 = new Scanner(System.in); //Creating scanner object
boolean end = false; //declaring the variable that will end the do while loop
do //do while loop is used so that the user gets taken to the main menu again and again
{
System.out.println("Welcome to the economic bot!");
System.out.println("Select one option to proceed");
System.out.println("1. Login");
System.out.println("2. Register");
int choice = s1.nextInt(); //accepting user's choice
switch (choice) {
case 1:
System.out.println("Enter your username:");
String userID = s1.next(); //taking user credentials
System.out.println("Enter your password");
String userPass = s1.next();
boolean validated = obj.Verify(userID,userPass);
if (validated == true) { //if the login details are correct
System.out.println("Login Successful!");
System.out.println("Redirecting...");
System.out.println();
end = true;
Game(uniUserID);
}
else { //if the details entered are wrong
System.out.println("Login failed! Possibly due to wrong user credentials.");
System.out.println("Please try again!");
}
break;
case 2:
System.out.println("Enter the username you'd like to keep:");
String regUserID = s1.next(); //accepting user details
System.out.println("Enter the password:");
String regUserPass = s1.next();
obj.Write(regUserID,regUserPass);
break;
default:
System.out.println("Invalid Option chosen."); // In case the user enters a wrong choice
}
}
while (!end); // condition for the initial do loop
}
}
最佳答案
尝试下面的代码:
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.util.Scanner;
import java.util.UUID;
public class Verification {
static File credentials = new File("C:\\Users\\user\\IdeaProjects\\Economic Bot\\out\\userData.txt"); //Clarifying filepath
static String uniUserID = " ";
static File gameData = new File("C:\\Users\\user\\IdeaProjects\\Economic Bot\\out\\gameData.txt");
public boolean Verify(String ID, String Pass) {
String tempName = " "; //the data read from the .txt file would be stored in these temporary variables
String tempPass = " ";
boolean found = false;//declaring some boolean variables so that the do while and if else statements work smoothly
boolean verified = false;
try //Try and catch block is initialized in case the file is not found
{
do {
Scanner s2 = new Scanner(credentials); //Reading the .txt file
s2.useDelimiter("[,\n]");// The file reader will stop once it encounters any of the following delimiters
while (s2.hasNext() && !found) {
tempName = s2.next(); //assigning the data read from the file to these variables
tempPass = s2.next();
uniUserID = s2.next();
if (tempName.trim().equals(ID) && tempPass.trim().equals(Pass))//comparing the data read from the file and the data entered by the user
{
verified = true;
found = true;
}
}
}
while (found = false);
} catch (Exception ex) {
System.out.println("Error");
}
return verified;
}
public void Write(String newUser, String newPass) {
String uniID = " ";
try {// try catch is used in case the file is not found
uniID = UUID.randomUUID().toString();
FileWriter writer = new FileWriter(credentials, true);// initializing the FileWriter, to make sure that it doesn't overwrite true is used so that it appends
BufferedWriter buffwrite = new BufferedWriter(writer); // creating buffered writer object
buffwrite.write("\n"); // Writing the new user's credentials into the .txt file
buffwrite.write(newUser);
buffwrite.write(",");
buffwrite.write(newPass);
buffwrite.write(",");
buffwrite.write(uniID);
buffwrite.close();
} catch (Exception ex) {
System.out.println("Error");
}
try {
FileWriter writer2 = new FileWriter(gameData, true);
BufferedWriter buffwrite2 = new BufferedWriter(writer2);
buffwrite2.write("\n");
buffwrite2.write(uniID);
buffwrite2.write(",");
buffwrite2.write("0");
buffwrite2.close();
} catch (Exception ex) {
System.out.println("Error");
}
}
public static void Game(String uniqueID) throws FileNotFoundException {
Scanner s3 = new Scanner(gameData);
String waste = " ";
String coins = " ";
while (s3.hasNextLine()) {
String fileLine = s3.nextLine();
if (fileLine.contains(uniUserID)) {
/*s3.useDelimiter(("[\n]"));
s3.skip(uniUserID);
coins = s3.next();*/
coins = fileLine.split(",")[1];
break;
}
}
System.out.println(coins);
}
public static void main(String[] args) throws FileNotFoundException {
Verification obj = new Verification();
Scanner s1 = new Scanner(System.in); //Creating scanner object
boolean end = false; //declaring the variable that will end the do while loop
do //do while loop is used so that the user gets taken to the main menu again and again
{
System.out.println("Welcome to the economic bot!");
System.out.println("Select one option to proceed");
System.out.println("1. Login");
System.out.println("2. Register");
int choice = s1.nextInt(); //accepting user's choice
switch (choice) {
case 1:
System.out.println("Enter your username:");
String userID = s1.next(); //taking user credentials
System.out.println("Enter your password");
String userPass = s1.next();
boolean validated = obj.Verify(userID, userPass);
if (validated == true) { //if the login details are correct
System.out.println("Login Successful!");
System.out.println("Redirecting...");
System.out.println();
end = true;
Game(uniUserID);
} else { //if the details entered are wrong
System.out.println("Login failed! Possibly due to wrong user credentials.");
System.out.println("Please try again!");
}
break;
case 2:
System.out.println("Enter the username you'd like to keep:");
String regUserID = s1.next(); //accepting user details
System.out.println("Enter the password:");
String regUserPass = s1.next();
obj.Write(regUserID, regUserPass);
break;
default:
System.out.println("Invalid Option chosen."); // In case the user enters a wrong choice
}
}
while (!end); // condition for the initial do loop
}
}
建议:
- 尝试在每行末尾而不是开头添加一个新行 (
\n
) 字符,因为它会在文件开头添加一个空行。 - 如果找到 ID 匹配,则中断循环。
关于java - 如何在 .txt 文件中查找字符串,然后读取其后面的数据,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/70605738/