java - 数字格式异常 : For input string: "[memorylocation" java

Question

我正在做一项作业，其目标之一是添加两个大整数。这是我的代码，分为四个文件。

我们无法更改的主要内容:

import java.util.*;
import MyUtils.MyUtil;

public class CSCD210HW7
{
   public static void main(String [] args)throws Exception
   {
      int choice;
      String num;
      LargeInt one, two, three = null;
      Scanner kb = new Scanner(System.in);

      num = HW7Methods.readNum(kb);
      one = new LargeInt(num);

      num = HW7Methods.readNum(kb);
      two = new LargeInt(num);

      do
      {
         choice = MyUtil.menu(kb);

         switch(choice)
         {
            case 1:  System.out.println(one + "\n");
                     break;

            case 2:  System.out.println("The value of the LargeInt is: " + two.getValue() + "\n");
                     break;

            case 3:  num = HW7Methods.readNum(kb);
                     one.setValue(num);
                     break;

            case 4:  if(one.equals(two))
                        System.out.println("The LargeInts are equal");
                     else
                        System.out.println("The LargeInts are NOT equal");        
                     break;

            case 5:  three = two.add(one);
                     System.out.printf("The results of %s added to %s is %s\n", one.getValue(), two.getValue(), three.getValue());
                     break;  

            case 6:  HW7Methods.displayAscendingOrder(one, two, three);
                     break;

            default:  if(two.compareTo(one) < 0)
                        System.out.printf("LargeInt %s is less than LargeInt %s\n", two.getValue(), one.getValue());   
                     else if(two.compareTo(one) > 0)
                        System.out.printf("LargeInt %s is greater than LargeInt %s\n", two.getValue(), one.getValue());
                     else
                        System.out.printf("LargeInt %s is equal to LargeInt %s\n", two.getValue(), one.getValue());      
                     break;
         }// end switch

      }while(choice != 8);

   }// end main

}// end class

LargeInt 类(我们创建的自定义类)

public class LargeInt implements Comparable<LargeInt>
{
   private int[]myArray;

   private LargeInt()
   {
      this("0");
   }

   public LargeInt(final String str)
   {
      this.myArray = new int[str.length()];
      for(int x = 0; x < this.myArray.length; x++)
      {
         this.myArray[x] = Integer.parseInt(str.charAt(x)+ "");
      }
   }

   public LargeInt add(final LargeInt passedIn)
   {
      String stringOne = myArray.toString();
      String stringTwo = passedIn.myArray.toString();

      int r = Integer.parseInt(stringOne);
      int e = Integer.parseInt(stringTwo);
      int s = r + e;
      return new LargeInt(""+s);
   }

   public void setValue(final String arrayString)
   {
      this.myArray = new int[arrayString.length()];
      for(int x = 0; x < myArray.length; x++)
      {
        this.myArray[x]=arrayString.charAt(x);
      }
   }

   @Override
   public int compareTo(LargeInt passedIn)
   {
      if(passedIn == null)
      {   
         throw new RuntimeException("NullExceptionError");
      }   
      int ewu = 0;
      int avs = 0;

      if(this.myArray.length != passedIn.myArray.length)
      {   
         return this.myArray.length - passedIn.myArray.length;
      }
      for(int i = 0; i < this.myArray.length -1; i++)
      {
         if(this.myArray[i] != passedIn.myArray[i])
         {
            return this.myArray[i]-passedIn.myArray[i];
         }
      }
      return ewu-avs;
   }
   public int hashCode()
   {
      String p = "";
      for(int f = 0; f < this.myArray.length; f++)
      {
         p += myArray[f]; 
      }

      return p.hashCode();
   }

   public String getValue()
   {
      String h = "";
      for(int t = 0; t < this.myArray.length; t++)
      {
         h += myArray[t]; 
      }
   return h;
   }   

   @Override
   public boolean equals(Object jbo)
   {
      if(jbo == null) 
      {   
         return false;
      }
      if(!(jbo instanceof LargeInt))
      {   
         return false;
      }
      LargeInt k =(LargeInt)jbo;
      if(k.myArray.length != this.myArray.length)
      {   
         return false;
      }   
      for(int d = 0; d < this.myArray.length; d++)
      {
         if(k.myArray[d] != myArray[d])
         {   
            return false;          
         }     
      }

      return true;
   }

   @Override
   public String toString()
   {
      String c = "";
      for(int q = 0; q < this.myArray.length; q++)
      {
         c += myArray[q]; 
      }
   return "The LargeInt is: " + c;
   }
 }

HW7Methods 文件

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

public class HW7Methods
{
   public static String readNum(Scanner kb)
   {
      String num = "";

      System.out.print("Enter Your Large Int: ");

      num = kb.nextLine();

      return num;
   }
   public static void displayAscendingOrder(final LargeInt first, final LargeInt second, final LargeInt third)
   {
      String highestInt;
      if(first.compareTo(second) >= 0 && first.compareTo(third) >= 0)
      {   
         highestInt = first.getValue();
      }
      else if(second.compareTo(first) >= 0 && second.compareTo(third) >= 0)
      {   
         highestInt = second.getValue();
      }
      else
      {   
         highestInt = third.getValue();
      }   
      String middleInt;
      if(first.compareTo(second) >= 0 && first.compareTo(third) <= 0)
      {   
         middleInt = first.getValue();
      }
      else if(second.compareTo(first) >= 0 && second.compareTo(third) <= 0)
      {
          middleInt = second.getValue();
      }
      else
      {
         middleInt = third.getValue();
      }   
      String lowestInt;
      if(first.compareTo(second) <= 0 && first.compareTo(third) <= 0)
      {
         lowestInt = first.getValue();
      }
      else if(second.compareTo(first) <= 0 && second.compareTo(third) <= 0)
      {
         lowestInt = second.getValue();
      }
      else
      {
         lowestInt = third.getValue();
      }   
      System.out.println("The LargeInts in order are: " + lowestInt + ", " + middleInt + ", " + highestInt);

   }
}

MyUtil 文件

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

public class MyUtil
{  
   public static int menu(Scanner kb)
   {
      int userChoice;
      System.out.println("1) Print First Int");
      System.out.println("2) Print Second Int");
      System.out.println("3) Add Different Int");
      System.out.println("4) Check If Equal");
      System.out.println("5) Add Large Ints");
      System.out.println("6) Display In Ascending Order");
      System.out.println("7) Compare Ints");
      System.out.println("8) Quit");



      kb = new Scanner(System.in);

      System.out.print("Please Select Your Choice: ");
      userChoice = kb.nextInt();

      while(userChoice < 1 || userChoice > 8)
      {
         System.out.print("Invalid Menu Choice. Please Re-Enter: ");
         userChoice = kb.nextInt();
      }

      return userChoice;
   }
}

当我运行此代码时，它会像预期那样提示我输入两个大整数。但是，当我选择选项 5 添加它们时，我得到的是:

Exception in thread "main" java.lang.NumberFormatException: For input string: "[I@55f96302"
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Integer.parseInt(Integer.java:580)
    at java.lang.Integer.parseInt(Integer.java:615)
    at LargeInt.add(LargeInt.java:24)
    at CSCD210HW7.main(CSCD210HW7.java:41)

我以前从未见过这种类型的错误。谁能告诉我发生了什么事吗？

Answer 1

For input string: "[I@55f96302

这不是您要在此处解析的“正确”字符串。

这就是调用 toString() 时 int[] 的样子。

String stringOne = myArray.toString();

你为什么要这么做？那应该做什么？

int r = Integer.parseInt(stringOne);
int e = Integer.parseInt(stringTwo);
int s = r + e;

从表面上看，您尝试使用 LargeInt 类通过某种方式将“大”整数存储在整数数组中来处理它们。没关系，BigInteger 也可以这样工作(或多或少)，但是你不能仅仅通过尝试转换回 int 来进行计算(毕竟这些数字对于计算来说太大了)即使您正确地进行了字符串解析，也要处理 int 算术)。