简单二进制代码转换器的异常

Question

我在Java（applet）中的简单二进制代码转换器遇到了一个问题：

import java.awt.*;
import java.awt.event.*;
import java.applet.Applet;

public class dual_convert extends Applet implements ActionListener{
  TextField dual;
  TextField decimal;
  Button dual_b;
  Button decimal_b;
  Label dual_l;
  Label decimal_l;
  int decimal_i;
  String dual_s [];
  int dual_i;
  int decimal_e;

  public void init() {
    setLayout(null);

    dual = new TextField();
    dual.setBounds(90,10,100,25);
    add(dual);

    decimal = new TextField();
    decimal.setBounds(90,40,100,25);
    add(decimal);

    decimal_l = new Label("Decimal:");
    decimal_l.setBounds(10,40,80,25);
    add(decimal_l);

    dual_l = new Label("Binary:");
    dual_l.setBounds(10,10,80,25);
    add(dual_l);

    dual_b = new Button ("Convert");
    dual_b.setBounds(200,10,80,25);
    add(dual_b);
    dual_b.addActionListener(this);

    decimal_b = new Button ("Convert");
    decimal_b.setBounds(200,40,80,25);
    add(decimal_b);
    decimal_b.addActionListener(this);

  }

  public void actionPerformed (ActionEvent e) {
    if (e.getSource()==decimal_b) {
      decimal_i = Integer.parseInt(decimal.getText());  
      int ih = 0;
      dual.setText("");
      while (decimal_i>0) {
        dual.setText((decimal_i % 2)+dual.getText());
        decimal_i = decimal_i / 2; 
        ih++;
      }    
    }

    if (e.getSource()==dual_b) {
      dual_s = dual.getText().split("");
      dual_i = dual_s.length;
      decimal.setText("");
      for (int i=0;dual_i>0;dual_i--) {
        decimal_e = decimal_e + (Integer.parseInt(dual_s[dual_i]) * 2^i); 
        i++;
      } 
      decimal.setText(decimal_e+"");       
    } 
  }
}

线程“AWT-EventQueue-1”中的异常java.lang.ArrayIndexOutoFBoundsException：8在Dual.ActionPerformed(dual.java:65)在java.awt.Button.ProcessActionEvent（Button.java:409)在java.awt.Button.ProcessEvent（Button.java:377)在java.awt.Component.DispatchEventImpl（Component.java:4861)在java.awt.Component.DispatchEvent（ectionPrivilege(ProtectionDomain.java:76)在java.awt.EventQueue.DispatchEvent（EventQueue.java:699)在java.awt.EventDispatchThread.PumponeEventForFilters（EventDispatchThread.java:242)在java.awt.EventDispatchThread.PumpEventSforFilter（EventDispatchThread.java:161)在

对于二进制-->十进制转换，我使用这个系统（还有其他系统吗？）：

100101=[(1)×25]+[(0)×24]+[(0)×23]+[(1)×22]+[(0)×21]+[(1)×20]

100101=[1×32]+[0×16]+[0×8]+[1×4]+[0×2]+[1×1]

100101=3710

线程“AWT-EventQueue-1”java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)在java.lang.Integer.ParseInt(Integer.java:504)在java.lang.Integer.ParseInt(Integer.java:527)在DUAL_CONVER.ActionPerforded(DUAL_CONVER.JAVA:64)在java.awt.Button.ProcessActionEvent（Button.java:409)在java.awt.Button.ProcessEvent（java.awt.EventQueue$4。在java.awt.EventQueue$4处运行(EventQueue.java:700)在java.security.AccessController.DoPrivileed（本机方法）在java.security.ProtectionDomain$1处运行(EventQueue.java:76)在java.awt.EventQueue.DispatchEventEventForFilters（EventDispatchThread.PumpEventSforFilters（EventDispatchThread.java:699)在

Answer 1

问题就在这里：

 for (int i=0;dual_i>0;dual_i--) {
    decimal_e = decimal_e + (Integer.parseInt(dual_s[dual_i - 1]) * 2^i); 
    i++;
  } 

您应该使用dual_s[dual_i-1]而不是dual_s[dual_i]，因为dual_i=dual_s.length；和数组索引以0开头