java - 如何从文件中检索数据

Question

我应该如何检索 text1 文件以用作登录信息..因为我已经在注册部分输入了详细信息..我想使用名字和员工 ID 作为登录部分的用户名和密码..p/s:我在编码方面很弱..所以请原谅我凌乱的编码:)这是我的代码。

import java.util.Scanner;
import java.io.*;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.FileReader;


public class TestMyException12 {

static void clear() {
    try {
        if (System.getProperty("os.name").contains("Windows"))
            new ProcessBuilder("cmd", "/c", "cls").inheritIO().start().waitFor();
        else
            Runtime.getRuntime().exec("clear");
    } catch (IOException | InterruptedException ex) {}
}


public static void main(String[] args) {


System.out.println("1.Please register for new staff\n2.Staff login\n");
Scanner input1 = new Scanner(System.in);

FileWriter fWriter = null;
BufferedWriter writer = null;
int choice = input1.nextInt();




if (choice == 1) {
    System.out.println("======================Staff Registration==================\n");
    System.out.println("Please enter your personal details below:\n");

    System.out.println("Enter your first name:\n");
    Scanner scan = new Scanner(System.in);
    String text = scan.nextLine();

    System.out.println("Enter your last name:\n");
    Scanner scan1 = new Scanner(System.in);
    String text1 = scan.nextLine();

    System.out.println("Enter your NRIC:\n");
    Scanner scan2 = new Scanner(System.in);
    String text2 = scan.nextLine();

    System.out.println("Enter your Staff ID:\n");
    Scanner scan3 = new Scanner(System.in);
    String text3 = scan.nextLine();

    System.out.println("Enter your position:\n");
    Scanner scan4 = new Scanner(System.in);
    String text4 = scan.nextLine();

    try {
        fWriter = new FileWriter("text1.txt");
        writer = new BufferedWriter(fWriter);
        writer.write(text);
        writer.write(text1);
        writer.write(text2);
        writer.write(text3);
        writer.write(text4);
        writer.newLine();
        writer.close();
        System.err.println("Your input data " + text.length() + " was saved.");
    } catch (Exception e) {
        System.out.println("Error!");
    }
}
else {
    System.out.println("======================Staff Login===========================");

    System.out.println("\nLogin(Use your first name as username and id as password)");

    System.out.println("Enter Username : ");
    Scanner scan = new Scanner(System.in);
    String text = scan.nextLine();

    System.out.println("Enter Password : ");
    Scanner scan3 = new Scanner(System.in);
    String text3 = scan.nextLine();

    if (scan.equals(text) && scan.equals(text3)) {
        clear();
        System.out.println("Access Granted! Welcome!");
    } else if (scan.equals(text)) {
        System.out.println("Invalid Password!");
    } else if (scan.equals(text3)) {
        System.out.println("Invalid Username!");
    } else {
        System.out.println("Please register first!\n");
    }
}
}
}

Answer 1

很简单，就像这样:

package com.coder.singleton;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;

public class TestMyException12 {
    static void clear() {
    try {
        if (System.getProperty("os.name").contains("Windows"))
            new ProcessBuilder("cmd", "/c", "cls").inheritIO().start().waitFor();
        else
            Runtime.getRuntime().exec("clear");
    } catch (IOException | InterruptedException ex) {
    }
}

public static void main(String[] args) {

    System.out.println("1.Please register for new staff\n2.Staff login\n");
    Scanner input1 = new Scanner(System.in);

    FileWriter fWriter = null;
    BufferedWriter writer = null;
    int choice = input1.nextInt();
    StringBuilder sb = new StringBuilder();
    String text = "";

    if (choice == 1) {
        System.out.println("======================Staff Registration==================\n");
        System.out.println("Please enter your personal details below:\n");

        System.out.println("Enter your first name:\n");
        text = input1.next();
        sb.append(text + "  ");

        System.out.println("Enter your last name:\n");
        text = input1.next();
        sb.append(text+ "   ");

        System.out.println("Enter your NRIC:\n");
        text = input1.next();
        sb.append(text+ "   ");

        System.out.println("Enter your Staff ID:\n");
        text = input1.next();
        sb.append(text+ "   ");

        System.out.println("Enter your position:\n");
        text = input1.next();
        sb.append(text+ "   ");
        input1.close();
        try {
            fWriter = new FileWriter("text1.txt");
            writer = new BufferedWriter(fWriter);
            writer.write(sb.toString());
            writer.newLine();
            writer.close();
            System.err.println("Your input data " + sb.length() + " was saved.");
        } catch (Exception e) {
            System.out.println("Error!");
        }

    }

    else {

        String savedName = "";
        String savedPassword = "";

        try {
            FileInputStream fis = new FileInputStream(new File("text1.txt"));
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(fis, "UTF-8"));

            String word = "";
            String [] arr = null;
            while ((word = bufferedReader.readLine())!= null) {

                arr = word.split("\\s+");

            }
            savedName = arr[0];
            savedPassword = arr[2];
            bufferedReader.close();


        } catch (Exception e) {
            // TODO: handle exception
        }

        System.out.println("======================Staff Login===========================");

        System.out.println("\nLogin(Use your first name as username and id as password)");

        System.out.println("Enter Username : ");
        String userName = input1.next();

        System.out.println("Enter Password : ");
        String password = input1.next();




        if (userName.equals(savedName) && password.equals(savedPassword)) {
            clear();
            System.out.println("Access Granted! Welcome!");
        }else if (userName.equals(savedName) && !password.equals(savedPassword)) {
            System.out.println("Invalid Password!");
        } else if (!userName.equals(savedName) && password.equals(savedPassword)) {
            System.out.println("Invalid Username!");
        } else {
            System.out.println("Please register first!\n");
        }

    }
}
}