我有一个字符串构建器来加载一些字符串列表，我的问题是当我添加到textarea时我想替换那里的内容而不仅仅是添加它...我发布的所有代码都是很多，所以我会进一步解释是否有人需要其他信息。我认为问题是当我在附加时使用.toString（）方法转换stringbuilder时，可能每次都会添加到列表中，如果是这种情况，我不知道如何解决这个问题...
import java.awt.GridLayout;
import javax.swing.JFrame;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import java.io.*;
import java.util.Scanner;
import java.util.Arrays;
import javax.swing.JComboBox;
public class Lab10 extends JPanel
{
private StringBuilder string, string2, string3, string4; //loads SuperStrings faster by appending all at once
private JRadioButton occurrence, alphabetical;
private JPanel text;
private JComboBox<Integer> input;
private JLabel label, file1,file2, unique, unique2;
private JButton load, go,go2;
private CountLinkedList<SuperString> words, words3; //Change impliments CountList to extends BinaryCountTree
private OrderedLinkedList<SuperString> words2, words4;//Change impliments CountList to extends BinaryCountTree
private String filename,filename2;
private int width = 450;
private int height = 550;
private TextArea textarea,textarea2;
Scanner scan;
public Lab10()
{
string = new StringBuilder();
string2 = new StringBuilder();
string3 = new StringBuilder();
string4 = new StringBuilder();
ButtonListener listener = new ButtonListener();
Button2Listener listener2 = new Button2Listener();
Integer [] select = {1,2,3,4};
input = new JComboBox<Integer>(select);
text = new JPanel(new GridLayout(1,2));
go = new JButton("Select Text File 1: ");
go2 = new JButton("Select Text File 2: ");
label = new JLabel("N: " );
unique = new JLabel("");
unique2 = new JLabel("");
file1 = new JLabel("");
file1.setFont(new Font("Helvetica",Font.PLAIN,24));
unique.setFont(new Font("Helvetica",Font.PLAIN,24));
file2 = new JLabel("");
file2.setFont(new Font("Helvetica",Font.PLAIN,24));
unique2.setFont(new Font("Helvetica",Font.PLAIN,24));
occurrence= new JRadioButton("Occurrence");
occurrence.setMnemonic(KeyEvent.VK_O);
occurrence.addActionListener(listener);
occurrence.addActionListener(listener2);
occurrence.setSelected(true);
alphabetical = new JRadioButton("Alphabetical");
alphabetical.setMnemonic(KeyEvent.VK_A);
alphabetical.addActionListener(listener);
alphabetical.addActionListener(listener2);
ButtonGroup group = new ButtonGroup();
group.add(occurrence);
group.add(alphabetical);
go.addActionListener(listener);
go2.addActionListener(listener2);
input.addActionListener(listener);
input.addActionListener(listener2);
textarea = new TextArea("",0,0,TextArea.SCROLLBARS_VERTICAL_ONLY);
textarea2 = new TextArea("",0,0,TextArea.SCROLLBARS_VERTICAL_ONLY);
textarea.setFont(new Font("Helvetica",Font.PLAIN,24));
textarea2.setFont(new Font("Helvetica",Font.PLAIN,24));
textarea.setPreferredSize(new Dimension(width,height));
textarea2.setPreferredSize(new Dimension(width,height));
setPreferredSize(new Dimension(1000,700));
text.add(textarea);
text.add(textarea2);
add(occurrence);
add(alphabetical);
add(label);
add(input);
add(go);
add(file1);
add(unique);
add(go2);
add(file2);
add(unique2);
add(text);
textarea.setText("No File Selected");
textarea2.setText("No File Selected");
}
public class ButtonListener implements ActionListener //makes buttons do things
{
JFileChooser chooser = new JFileChooser("../Text");
public void actionPerformed(ActionEvent event)
{
Integer N = input.getSelectedIndex()+1;
if(event.getSource() == go)
{
int returnvalue = chooser.showOpenDialog(null);
if(returnvalue == JFileChooser.APPROVE_OPTION)
{
try
{
File file = chooser.getSelectedFile();
String text1= file.getName();
file1.setText(text1);
filename = file.getName();
System.err.println(filename);
scan = new Scanner(file);
}
catch (IOException e)
{
System.err.println("IO EXCEPTION");
return;
}
}
else
{
return;
}
String[] storage = new String[N];
words = new CountLinkedList<SuperString>();
words2 = new OrderedLinkedList<SuperString>();
for(int i=1;i<N;i++)
storage[i] = scan.next().toLowerCase().replaceAll("[^A-Za-z0-9]", "")
.replaceAll("[.,':]","");
while(scan.hasNext())
{
for(int i=0;i<=N-2;i++)
storage[i] = storage[i+1];
storage[N-1] = scan.next().toLowerCase();
storage[N-1] = storage[N-1].replace(",","").replace(".","").replaceAll("[^A-Za-z0-9]", "")
.replaceAll("[.,':]","");
SuperString ss = new SuperString(storage);
SuperString ss2= new SuperString(storage);
words.add(ss );
words2.add(ss2 );
}
textarea.setText("");
}
SuperString[] ss = new SuperString[words.size()];
SuperString[] ss2 = new SuperString[words2.size()];
int i=0;
int count =0, count2= 0;
for(SuperString word: words)
{
ss[i] = word;
i++;
}
int j=0;
for(SuperString word: words2)
{
ss2[j] = word;
j++;
}
Arrays.sort(ss, new SuperStringCountOrder());
for(SuperString word : ss)
{
count++;
string.append(Integer.toString(count)+ " "+ word+ "\n");
}
if(occurrence.isSelected())
{
string.replace(0,0,"");
textarea.setText("");
textarea.append(" "+filename+" has wordcount: "+words.size()+
"\n-------------------------\n\n");
textarea.append(string.toString());
}
for(SuperString word : ss2)
{
count2++;
string2.append(Integer.toString(count2)+ " "+ word.toString()+ "\n");
}
if(alphabetical.isSelected())
{
string.replace(0,0,"");
textarea.setText("");
textarea.append(" "+filename+" has wordcount: "+words.size()+
"\n-------------------------\n\n");
textarea.append(string2.toString());
}
unique.setText("Unique Count: "+ Integer.toString(words.size()));
}
}
public class Button2Listener implements ActionListener
{
JFileChooser chooser = new JFileChooser("../Text");
public void actionPerformed(ActionEvent event)
{
Integer N = input.getSelectedIndex()+1;
if(event.getSource() == go2)
{
int returnvalue = chooser.showOpenDialog(null);
if(returnvalue == JFileChooser.APPROVE_OPTION)
{
try
{
File file = chooser.getSelectedFile();
String text2= file.getName();
file2.setText(text2);
filename2 = file.getName();
System.err.println(filename);
scan = new Scanner(file);
}
catch (IOException e)
{
System.err.println("IO EXCEPTION");
return;
}
}
else
{
return;
}
String[] storage = new String[N];
words3 = new CountLinkedList<SuperString>();
words4 = new OrderedLinkedList<SuperString>();
for(int i=1;i<N;i++)
storage[i] = scan.next().toLowerCase().replace(",","").replace(".","");
while(scan.hasNext())
{
for(int i=0;i<=N-2;i++)
storage[i] = storage[i+1];
storage[N-1] = scan.next().toLowerCase();
storage[N-1] = storage[N-1].replace(",","").replace(".","").replaceAll("[^A-Za-z0-9]", "")
.replaceAll("[.,':]","");
SuperString ss = new SuperString(storage);
SuperString ss2= new SuperString(storage);
words3.add(ss );
words4.add(ss2 );
}
textarea2.setText("");
}
SuperString[] sstwo = new SuperString[words3.size()];
SuperString[] ss2two = new SuperString[words4.size()];
int i=0;
int count =0, count2= 0;
for(SuperString word2: words3)
{
sstwo[i] = word2;
i++;
}
int j=0;
for(SuperString word2: words4)
{
ss2two[j] = word2;
j++;
}
Arrays.sort(sstwo, new SuperStringCountOrder());
for(SuperString word2 : sstwo)
{
count++;
string3.append(Integer.toString(count)+ " "+ word2+ "\n");
}
if(occurrence.isSelected())
{
textarea2.setText("");
textarea2.append(" "+filename2+" has wordcount: "+words3.size()+
"\n-------------------------\n\n");
textarea2.append(string3.toString());
}
for(SuperString word2 : ss2two)
{
count2++;
string4.append(count2+" "+ " "+word2+"\n");
}
if(alphabetical.isSelected())
{
textarea2.setText("");
textarea2.append(" "+filename2+" has wordcount: "+words3.size()+
"\n-------------------------\n\n");
textarea2.append(string4.toString());
}
unique2.setText("Unique Count: "+ Integer.toString(words3.size()));
}
}
public static void main(String[] arg)
{
JFrame frame = new JFrame("Lab 10");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new Lab10());
frame.pack();
frame.setVisible(true);
}
}
答案 0 :(得分：1)
看起来像你的＆＃34;字符串＆＃34;是一个StringBuilder实例变量，您永远不会重置它。你做了
textarea.setText("");
textarea.append(string.toString());
所以你要先按照自己的意愿清除textarea。但＆＃34; string＆＃34;的价值只有在我能看到的时候才会被追加。你想用
清除它吗？string.replace(0,0,"");
public class A {
public static void main(String[] args) {
StringBuilder sb = new StringBuilder();
sb.append("abcdefg");
System.out.println("String is [" +sb + "]");
sb.replace(0,0,"");
System.out.println("String is [" +sb + "]");
sb.replace(0,1000,"");
System.out.println("String is [" +sb + "]");
}
}
输出：
字符串是[abcdefg]
字符串是[abcdefg]
字符串是[]