java - 读取文本文件，然后将大写转换为小写并写入文本文件

Question

我试图读入一个文件，然后写入一个新文件，从而将输入文本文件中的大写字符在新的输出文件中更改为小写。 该文件将在没有 if 循环的情况下正常读取和写入，然后当我尝试实现 if 循环来更改大小写时，输出文件将打印空白。任何帮助将不胜感激。

import java.io.*;

public class TextFile {
    public static void main (String[] args) throws IOException {
                File file1 = new File("intext.txt");
                File file2 = new File("outtext.txt"); 
                char CharCounter = 0;       
                BufferedReader in = (new BufferedReader(newFileReader(file1)));
                PrintWriter out = (new PrintWriter(new FileWriter(file2)));

                int ch;
                while ((ch = in.read()) != -1)

                    if (Character.isUpperCase(CharCounter)){
                        Character.toLowerCase(CharCounter);
                        out.write(ch);
                    }

                in.close();
                out.close();
    }       
}

Answer 1

您的 CharCounter 始终为 0，并且您的比较不正确，请尝试如下操作:

import java.io.*;

public class TextFile {
    public static void main (String[] args) throws IOException {
        File file1 = new File("intext.txt");
        File file2 = new File("outtext.txt"); 
        char CharCounter = 0;       
        BufferedReader in = (new BufferedReader(newFileReader(file1)));
        PrintWriter out = (new PrintWriter(new FileWriter(file2)));
        int ch;
        while ((ch = in.read()) != -1){
            if (Character.isUpperCase(ch)){
                Character.toLowerCase(ch);

            }
            out.write(ch);
        }
        in.close();
        out.close();
    }       
}