java - 如何将这个程序中的第一个字母大写

Question

我已经写了大部分内容。我只是不知道如何将每行的第一个字母大写。问题是:

编写一个程序来检查文本文件中的几种格式和标点符号问题。该程序要求输入文件和输出文件的名称。然后它将所有文本从输入文件复制到输出文件，但有以下两个更改 (1) 任何包含两个或多个空白字符的字符串都被一个空白字符替换； (2) 所有句子都以大写字母开头。第一个句子之后的所有句子都以句号、问号或感叹号开头，后跟一个或多个空白字符。

我已经编写了大部分代码。我只需要帮助每个句子的第一个字母大写。这是我的代码:

import java.io.*;
import java.util.Scanner;


public class TextFileProcessor
{
public static void textFile()
{
    Scanner keyboard = new Scanner(System.in);

    String inputSent;
    String oldText;
    String newText;


    System.out.print("Enter the name of the file that you want to test: ");
    oldText = keyboard.next();

    System.out.print("Enter the name of your output file:");
    newText = keyboard.next();
    System.out.println("\n");

    try
    {
        BufferedReader inputStream = new BufferedReader(new FileReader(oldText));
        PrintWriter outputStream = new PrintWriter(new FileOutputStream(newText));
        inputSent = inputStream.readLine();

        inputSent = inputSent.replaceAll("\\s+", " ").trim();
        inputSent = inputSent.substring(0,1).toUpperCase() + inputSent.substring(1);

        inputSent = inputSent.replace("?", "?\n").replace("!", "!\n").replace(".", ".\n");
        //Find a way to make the first letter capitalized

        while(inputSent != null)
        {
            outputStream.println(inputSent);
            System.out.println(inputSent);
            inputSent = inputStream.readLine();
        }

        inputStream.close();
        outputStream.close();
    }

    catch(FileNotFoundException e)
    {
        System.out.println("File" + oldText + " could not be located.");
    }

    catch(IOException e)
    {
        System.out.println("There was an error in file" + oldText);
    }
}
}

---

import java.util.Scanner;
import java.io.*;


public class TextFileProcessorDemo
{
public static void main(String[] args)
{
    String inputName;
    String result;
    String sentence;


    Scanner keyboard = new Scanner(System.in);


    System.out.print("Enter the name of your input file: ");
    inputName = keyboard.nextLine();
    File input = new File(inputName);

    PrintWriter outputStream = null;

    try
    {
        outputStream = new PrintWriter(input);
    }

    catch(FileNotFoundException e)
    {
        System.out.println("There was an error opening the file. Goodbye!" + input);
        System.exit(0);
    }

    System.out.println("Enter a line of text:");
    sentence = keyboard.nextLine();

    outputStream.println(sentence);
    outputStream.close();

    System.out.println("This line was written to:" + " " + input);
    System.out.println("\n");

}
}

Answer 1

由于您的代码已经包含 inputSent = inputSent.substring(0,1).toUpperCase() + inputSent.substring(1); 我假设 inputSent 可以包含不止一个句子，或者可能只代表文件的一行和部分句子。

因此，我建议您首先将整个文件读入一个字符串(如果它不是太大)，然后对该字符串使用 split() 将其分解成单独的句子，将第一个大写角色并再次加入他们。

例子:

String[] sentences = fileContent.split("(?<=[?!.])\\s*");
StringBuilder result = new StringBuilder();
for( String sentence : sentences) {
  //append the first character as upper case
  result.append( Character.toUpperCase( sentence.charAt(0) ) );
  //add the rest of the sentence
  result.append( sentence.substring(1) );
  //add a newline
  result.append("\n");
}

//I'd not replace the input, but to be consistent with your code
fileContent = result.toString();