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如何從文件中檢索數據

2017-05-21 186 views
0

我應該如何檢索text1的文件以用作登錄信息。 因爲我已經在註冊部分中輸入了詳細信息..我想使用名字和職員ID作爲登錄部分的用戶名和密碼.. p/s：即時通訊如此薄弱的編碼..所以請原諒我的凌亂編碼:) 這裏是我的代碼。如何從文件中檢索數據

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"); 
    } 
} 
} 
}

來源

2017-05-21 MZ SYHD

回答

0

第一，你應該插入分離器（如換行）時保存寄存器信息到文件的text1，如果不是，則不能fields.for例如區分信息：

fWriter = new FileWriter("d:\\tmp\\pass.txt"); 
       writer = new BufferedWriter(fWriter); 
       writer.write(text); 
       writer.newLine(); //separator string 
       writer.write(text1); 
       writer.newLine(); 
       writer.write(text2); 
       writer.newLine(); 
       writer.write(text3); 
       writer.newLine(); 
       writer.write(text4); 
       writer.newLine(); 
       writer.close();

，然後，你應該獲取註冊信息（只是名字和工作人員）形式的文件text1.txt

BufferedReader reader=new BufferedReader(new FileReader("text1.txt")); 
      String firstName = reader.readLine(); 
      reader.readLine(); 
      reader.readLine(); 
      String passWord=reader.readLine();

決賽中，讀出的信息比較輸入信息。

if (firstName.equals(text) && passWord.equals(text3)) { 
       System.out.println("Access Granted! Welcome!"); 
      }

來源

2017-05-21 16:44:53 dabaicai

1

這很容易，做這樣的：

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"); 
     } 

    } 
} 
}

來源

2017-05-21 17:45:54

0

在登記時 你要插入一些分隔符（ ' ' '：''。'， '_'，「 - '等...）在註冊時。

現在聽到我正在使用「＃」分隔符。

插入數據和分隔符後。

現在讀取時您必須使用該分隔符分割才能訪問該數據。在陣列

見婁代碼...

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


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("#"); 
           writer.write(text1); 
           writer.write("#"); 
           writer.write(text2); 
           writer.write("#"); 
           writer.write(text3); 
           writer.write("#"); 
           writer.write(text4); 

           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(); 

     String datafile = ""; 

     try 
     { 
      FileReader fr = new FileReader("text1.txt"); 
      int i; 

      while((i = fr.read()) != -1) 
      { 
       datafile = datafile+(char)i; // store all data into String obj from File 
      } 
     } 
     catch(Exception e) 
     { 
      System.out.println("Error In Login : "+e); 
     } 


     String[] userval = datafile.split("#"); // split that data and create part of that data 

     for(int i = 0 ; i < userval.length ; i++) 
     { 
      System.out.println(i+">>>>>"+userval[i]); 
     } 
     // userval[] is array that is store all data from that file into part 

     // after you can put any condition 

     //System.out.println(text+">>>>>"+userval[0]); 
     //System.out.println(text3+">>>>>"+userval[3]); 

     if(text.equals(userval[0]) && text3.equals(userval[3])) 
     { 
      clear(); 
      System.out.println("Access Granted! Welcome!"); 
     } 
     else 
     { 
      System.out.println("Please register first!\n"); 
     } 
    } 
} 
}

來源

2017-05-21 18:08:08 Bhola

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