回文判断，可判断一句话

package homeWork;

import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JApplet;
import javax.swing.JLabel;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class Palindrome extends JApplet implements ActionListener{//判断是否为回文
 private static final long serialVersionUID = 1L;

 JTextField inpuTextField;
 JLabel inputLabel;
 JTextArea outputArea;
 boolean judge;
 String outputString;
 String input;
 char chars[];
 String changeString="";

 public void init() {
  Container container=getContentPane();
  container.setLayout(new FlowLayout());

  inputLabel=new JLabel("Please input:");
  container.add(inputLabel);

  inpuTextField=new JTextField(10);
  inpuTextField.addActionListener(this);
  container.add(inpuTextField);

  outputArea=new JTextArea();
  container.add(outputArea);
 }

 public void actionPerformed(ActionEvent event) {
  input=inpuTextField.getText();

  char array[]=input.toCharArray();

  change(array);//将数组转换为不含空格和标点符号

  judge=testPalindrome(changeString);
  display(judge);
 }

 public void change(char array[]) {
  int i=0;
  changeString="";

  for(;i<array.length;i++)
   if((array[i]>=65 && array[i]<=90)||(array[i]>=97 && array[i]<=122)) {
    changeString+=array[i];
   }
 }

 public boolean testPalindrome(String test) {
  char array[]=test.toCharArray();
  int n=array.length-1;

   for(int i=0;i<array.length/2;i++) {
    if(array[i]!=array[n])
     return false;
    else
     n--;
   }
   
  return true;
 }

 public void display(boolean judge) {
  outputString=input+" is ";

  if(judge)
   outputString+="a Palindrome.";
  else
   outputString+="not a Palindrome.";

  outputArea.setText(outputString);
 }
}