寫入或從文件讀取

Question

我想寫一個程序，用戶可以選擇將數據寫入文件或讀取文件。

我不知道爲什麼我的if-else if結構無法正常工作。當我嘗試查看數據時，程序將顯示數據，然後在不應該時請求更多輸入。

我會發布我希望有人可以幫助什麼似乎是一個愚蠢和簡單的問題。

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

public class Candy 
{ 
    public static void main(String[] args) 
    throws IOException 
    { 
     String candyname; 
     String input=""; 

     //create scanner object 
     Scanner keyboard=new Scanner(System.in); 

     System.out.print("[V]iew or [A]ppend Database (V or A)?===>"); 
     String choice=keyboard.nextLine(); 

     if (choice.equalsIgnoreCase("V")) 
     { 
      //open the file 
      File file=new File("candy"); 
      Scanner inputFile=new Scanner(file); 

      //display the lines 
      while (inputFile.hasNext()) 
      { 
       //read a line 
       candyname=inputFile.nextLine(); 

       //display a line 
       System.out.println(candyname); 
      } 

      //close the file 
      inputFile.close(); 

      System.out.println("\nComplete!"); 
     } 

     else if (choice.equalsIgnoreCase("A")); 
     { 
      //open the file 
      FileWriter fwriter=new FileWriter("candy", true); 

      System.out.println("Type 'end' to STOP entering names\n"); 
      do 
      { 
       //get the name of the candy 
       System.out.print("Enter the name of the candy===>"); 
       candyname=keyboard.nextLine(); 

       if (candyname.equalsIgnoreCase("end")) 
       { 
        //break; //breaks out of loop 
        //or use a null if clause (empty) 
       } 
       else if (!(candyname.equalsIgnoreCase("end"))) 
       { 
        //append to file 
        PrintWriter outputFile=new PrintWriter(fwriter); 
        outputFile.println(candyname); 
       }     

      }while (!(candyname.equalsIgnoreCase("end")));// || candyname !="END"); 

      //close the file 
      fwriter.close(); 

      System.out.println("\nComplete!"); 

     } 
    } 
} 

Answer 1

因爲您否則，如果被關閉

else if (choice.equalsIgnoreCase("A")); 

刪除分號;

else if (choice.equalsIgnoreCase("A"))