在Java中一起计算大写和小写字母

Question

好的！我有这个程序用于计算字符串中的单个字符。不管是大写还是小写。如果假设您输入一个字符串，然后询问字符'a'，则该程序可以工作，如果只有一个“A”，则计数将读取为零。如果我在 char 搜索中键入“A”，它将计为 1。我的问题是我需要 char 搜索来计算一个字符的所有实例，无论它是大写还是小写，并将它们一起计为一个字符数。

代码如下：

package index;

import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.LayoutManager;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.*;

public class Index extends JFrame
{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    protected JFrame mainFrame;
    protected JTabbedPane tabbedPane = new JTabbedPane(JTabbedPane.TOP);
    protected JPanel panel;
    private JTextArea textSearch;
    private JTextField charSearch;
    private JLabel message1;
    private JLabel message2;
    private char aChar;

    public Index()
    {

        mainFrame = new JFrame("Character Finder");
        mainFrame.setBounds(100, 100, 450, 300);
        mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        tabbedPane.setBounds(0, 0, 434, 261);

        mainFrame.getContentPane().add(tabbedPane);

        panel = new JPanel();
        tabbedPane.addTab("Index", panel);
        panel.setLayout(null);

        message1 = new JLabel("Enter text to be search: ");
        message1.setBounds(79, 55, 140, 27);
        panel.add(message1);

        textSearch = new JTextArea();
        textSearch.setBounds(220, 25, 223, 94);
        panel.add(textSearch);

        message2 = new JLabel("Enter a charater: ");
        message2.setBounds(179, 159, 100, 14);
        panel.add(message2);

        charSearch = new JTextField();
        charSearch.setBounds(285, 156, 64, 20);
        panel.add(charSearch);

        mainFrame.setSize(500, 350);
        mainFrame.setVisible(true);
        textSearch.setVisible(true);
        textSearch.setEditable(true);


        addWindowListener(new WindowAdapter()
        {
            public void windowClosing(WindowEvent e)
            {
                System.exit(0);
            }
        });

        TextSearchHandler tHandler = new TextSearchHandler();
        charSearch.addActionListener(tHandler);
    }


class TextSearchHandler implements ActionListener
{
    public void actionPerformed(ActionEvent e)
    {
        int count = 0;
        int current = 0;
        String instring;
        String inChar;


        instring = textSearch.getText();
        if(instring.equals(""))
        {
            instring = ("");
            textSearch.setText("");
        }

        inChar = charSearch.getText();
        if(inChar.equals(""))
        {
            inChar = ("");
            charSearch.setText("");
        }
        current = instring.indexOf(inChar, 0);

        while(current != -1)
        {

            inChar.equalsIgnoreCase(instring);
            aChar = instring.charAt(0);
            current = instring.indexOf(inChar, current + 1);
            count++;
        }

        JOptionPane.showMessageDialog(null, "Character " + "'" + inChar + "'" + " count: "
                    + count++, "Results", JOptionPane.PLAIN_MESSAGE);
    }
}
    public static void main(String[] args) 
    {
        new Index();
    }

}

当我进行字符搜索时，我必须输入两次。我必须输入大写版本来计算那个版本，删除那个，然后输入小写版本来计算那个。任何帮助，将不胜感激。

Answer 1

您可以在输入和要搜索的字母上使用String. toUpperCase() 看看tutorialspoint

Answer 2

比较时可以使用String的equalsIgnoreCase()方法

Answer 3

我对您的代码稍作修改，以接受有关搜索忽略大小写的用户输入。如果选中忽略大小写，则使用搜索字符串的小写版本和要搜索的文本完成搜索。您可以根据实际需要对其进行修改和增强

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class Index extends JFrame
{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    protected JFrame mainFrame;
    protected JTabbedPane tabbedPane = new JTabbedPane(JTabbedPane.TOP);
    protected JPanel panel;
    private JTextArea textSearch;
    private JTextField charSearch;
    private JLabel message1;
    private JLabel message2;
    private JCheckBox ignoreCaseCheck;
    public Index()
    {

        mainFrame = new JFrame("Character Finder");
        mainFrame.setBounds(100, 100, 450, 300);
        mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        tabbedPane.setBounds(0, 0, 434, 261);

        mainFrame.getContentPane().add(tabbedPane);

        panel = new JPanel();
        tabbedPane.addTab("Index", panel);
        panel.setLayout(null);

        message1 = new JLabel("Enter text to be search: ");
        message1.setBounds(79, 55, 140, 27);
        panel.add(message1);

        textSearch = new JTextArea();
        textSearch.setBounds(220, 25, 223, 94);
        panel.add(textSearch);

        message2 = new JLabel("Enter a charater: ");
        message2.setBounds(179, 159, 100, 14);
        panel.add(message2);

        charSearch = new JTextField();
        charSearch.setBounds(285, 156, 64, 20);
        panel.add(charSearch);

        ignoreCaseCheck = new JCheckBox("Ignore case while search.");
        ignoreCaseCheck.setBounds(179, 176, 200, 20);
        panel.add(ignoreCaseCheck);

        mainFrame.setSize(500, 350);
        mainFrame.setVisible(true);
        textSearch.setVisible(true);
        textSearch.setEditable(true);

        addWindowListener(new WindowAdapter()
        {
            public void windowClosing(WindowEvent e)
            {
                System.exit(0);
            }
        });

        TextSearchHandler tHandler = new TextSearchHandler();
        charSearch.addActionListener(tHandler);
    }

    class TextSearchHandler implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            int count = 0;
            int current = 0;
            String instring;
            String inChar;

            instring = ignoreCaseCheck.isSelected() == true ? textSearch.getText().toLowerCase() : textSearch.getText();
            if (instring.equals(""))
            {
                instring = ("");
                textSearch.setText("");
            }

            inChar = ignoreCaseCheck.isSelected() == true ? charSearch.getText().toLowerCase() : charSearch.getText();
            if (inChar.equals(""))
            {
                inChar = ("");
                charSearch.setText("");
            }
            current = instring.indexOf(inChar, 0);

            while (current != -1)
            {

                inChar.equalsIgnoreCase(instring);
                instring.charAt(0);
                current = instring.indexOf(inChar, current + 1);
                count++;
            }

            JOptionPane.showMessageDialog(null, "Character " + "'" + charSearch.getText() + "'" + " count: " + count++, "Results", JOptionPane.PLAIN_MESSAGE);
        }
    }

    public static void main(String[] args)
    {
        new Index();
    }

}`

Answer 4

谢谢大家，我从你们每个人那里得到了一些见解，我做了以下更改。

instring = textSearch.getText().toLowerCase();
        if(instring.equals(""))
        {
            instring = ("");
            textSearch.setText("");
        }

        inChar = charSearch.getText().toLowerCase();
        if(inChar.equals(""))
        {
            inChar = ("");
            charSearch.setText("");
        }
        current = instring.indexOf(inChar, 0);

        while(current != -1)
        {

            inChar.equalsIgnoreCase(instring);
            aChar = instring.charAt(0);
            current = instring.indexOf(inChar, current + 1);
            count++;
        }

        JOptionPane.showMessageDialog(null, "Character " + "'" + charSearch.getText() + "'" + " count: "
                    + count++, "Results", JOptionPane.PLAIN_MESSAGE);

现在完美运行！！！我很感激！