为什么我收到错误“线程中的异常”AWT-EventQueue-0“java.lang.ArithmeticException：/ by zero”？

Question

 Exception in thread "AWT-EventQueue-0" java.lang.ArithmeticException: / by zero at factoroperations.compute(factoroperations.java:21) at factorframe$buttonhandler.actionPerformed(factorframe.java:71) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:20 18) at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.jav a:2341) at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel .java:402) at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259 ) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonL istener.java:252) at java.awt.Component.processMouseEvent(Component.java:6504) at javax.swing.JComponent.processMouseEvent(JComponent.java:3321) at java.awt.Component.processEvent(Component.java:6269) at java.awt.Container.processEvent(Container.java:2229) at java.awt.Component.dispatchEventImpl(Component.java:4860) at java.awt.Container.dispatchEventImpl(Container.java:2287) at java.awt.Component.dispatchEvent(Component.java:4686) at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832 ) at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492) at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422) at java.awt.Container.dispatchEventImpl(Container.java:2273) at java.awt.Window.dispatchEventImpl(Window.java:2713) at java.awt.Component.dispatchEvent(Component.java:4686) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707) at java.awt.EventQueue.access$000(EventQueue.java:101) at java.awt.EventQueue$3.run(EventQueue.java:666) at java.awt.EventQueue$3.run(EventQueue.java:664) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDo main.java:76) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDo main.java:87) at java.awt.EventQueue$4.run(EventQueue.java:680) at java.awt.EventQueue$4.run(EventQueue.java:678) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDo main.java:76) at java.awt.EventQueue.dispatchEvent(EventQueue.java:677) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThre ad.java:211) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread. java:128) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThre ad.java:117) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105) at java.awt.EventDispatchThread.run(EventDispatchThread.java:90) 

//Project: A program that factors numbers

//This defines the properties of the user interface

import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.Font;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JTextField;
import javax.swing.JLabel;

public class factorframe extends JFrame
{//declare all the variables
    private JLabel integerlabel;
    private JTextField integerfield;
    private JLabel factorslabel;
    private JTextField factorsfield;
    private JLabel namelabel;
    private JButton computebutton;
    private JButton clearbutton;
    private JButton exitbutton;
    private String integerstring;
    private long integer;
    private String factorsstring;
    private int factors;
    private factoroperations factormachine;

 public factorframe() //This is the constructor
 {  //add all buttons and fields
    super("Factor Frame");
    setLayout(new FlowLayout());
    namelabel = new JLabel("Integer Factorization  By Michael Daigh");
    add(namelabel);
    integerlabel = new JLabel("Enter an integer:");
    add(integerlabel);
    integerfield = new JTextField(20);
    add(integerfield);
    factorslabel = new JLabel("The factors are:");
    add(factorslabel);
    factorsfield = new JTextField(20);
    add(factorsfield);
    computebutton = new JButton("Compute Factors");
    add(computebutton);
    clearbutton = new JButton("Clear");
    add(clearbutton);
    exitbutton = new JButton("Exit");
    add(exitbutton);
    buttonhandler myhandler = new buttonhandler();
    computebutton.addActionListener(myhandler);
    clearbutton.addActionListener(myhandler);
    exitbutton.addActionListener(myhandler);
    factormachine = new factoroperations();
 }//End of constructor method
 private class buttonhandler implements ActionListener
   {public void actionPerformed(ActionEvent event)
        {
            if(event.getSource() == computebutton)//if user clicks compute factors
            {//computes the factors of the number
                integerstring = integerfield.getText();//get the number
                integer = Long.parseLong(integerstring);
                factorsstring = factoroperations.compute(integer);
                factorsfield.setText(factorsstring);//display the factors
            }
            else if(event.getSource() == clearbutton)//if user clicks clear
            {//clears all data in integer field and factor field
                integer=0;
                integerfield.setText("");
                factors=0;
                factorsfield.setText("");
            }
            else if(event.getSource() == exitbutton)//if user clicks exit
            {//exits the program
                System.exit(0);
            }
            else
                System.out.println("Unknown error");
        }//End of actionPerformed
    }//End of buttonhandler class
}//End of factorframe class


//Project: A program that factors numbers

//This contains the algorithm used by this project.

public class factoroperations
{
 public static String compute(long integer)
 {
    String factor="";//initialize the factor string
    int check = 1;//initialize the prime check
    for(int i=2; i<=integer/2; i++)
    {
        if(integer%i==0)//i is a factor of the number
        {
            for(int k=2; k<i; k++)//check if it is prime
            {
                if(i%k ==0)
                {
                    check = 1;
                    break;
                }
                else
                    check = 0;
            }
            if(check == 0 || i == 2)//display the prime factors only
            {
                factor = factor + " " + i + "P";
            }
            else if(check == 1)//display all other factors
                factor = factor + " " + i;
        }
    }
    if(factor == "")//if number does not factor, it is already prime
    {
        factor = "No factors. It is a prime number";
    }
    return factor;
 }
}//End factoroperations class


//Project: A program that factors numbers

//This activates the user interface.
import javax.swing.JFrame;
public class testfactor
{public static void main(String[] args)
    {factorframe myframe = new factorframe();
     myframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     myframe.setSize(325,225);
     myframe.setVisible(true);
    }//End of main
}//End of class testfactor

Answer 1

你得到int溢出并除以0.虽然integer参数是一个long，你的i是一个int，如果它试图增加以匹配大long参数的大小，它会溢出，当它溢出时，它值可以是0，负数，或者领主知道什么。

一种可能的解决方案：你的for循环索引应该都是long，而不是int。

而且，对于它的价值而言，给一个长参数或变量名称integer是非常困惑的！

Answer 2

你永远不会除以0，所以它不应该产生这个错误，这里搞砸了。 但是，我想指出一些问题需要解决：

• 不要调用你的long整数; 这简直太愚蠢了。 给它一个更有意义的名称，例如numberToFactor或只是number 。
• “ if(factor == "") ”：使用if(factor.equals(""))代替，你必须在字符串上使用.equals而不是==
• 阅读StringBuilder ; 您可以使用它来使代码更有效，并在for循环中使用所有字符串连接。

编辑：通过评论中的这一新信息，Hovercraft是对的。 将您的循环计数器更改为类型为long ，就像您要考虑的数字一样。 如果它们是int，当它们达到2 ^ 31-1（最大int值）时，它们将导致错误。 然而，使用long可以为数字提供更多内存，从而使其更大。