如何在 java 中将字符插入到一行的特定位置？-解网

问：

我环顾四周，没有找到任何我真正理解或可以做的事情，我希望有一个简单的解决方案。我必须在此程序中每行之后的第 20 个字符槽中添加一个。*

这是我的代码：

package StarBorder;

import java.util.Scanner;

public class NewTry {

    public static void main(String[] args) {
        System.out.println("Please input a word: ");
        Scanner stringScanner = new Scanner(System.in);
        String input = stringScanner.nextLine();
        int numberOfCharacters = 20;
        System.out.println("**********************");
        for (int i = 0; i < input.length(); i += numberOfCharacters) {
            String part = input.substring(i, Math.min(input.length(), i + numberOfCharacters));
            System.out.println("*" + part + "*");
        }
        System.out.println("**********************");
    }
}

这是它打印出来的内容：

**********************
*Hello I am doing som*
*e code, hello ther p*
*eople on stack overf*
*low* // I need this to be over where the other *'s are.
**********************

我需要它是一个完整的星星正方形。感谢您的任何回答。

我也希望它不是在第二十个字符处切断，而是在那之前的空间处切断。然而，这是一个次要问题。

java for 循环子字符串 java.util.scanner

您正在寻找“如何在 Java 中填充字符串”，以用于您标记的情况。如果需要在第 20 位，并且您的字符串只有四个字母长，那么在写入之前，您将需要（20 - 5）个空格。值得庆幸的是，在 SO 上有几个关于如何在 Java 中填充字符串的简单答案。**

0赞 user3437460 3/8/2023

只需搜索空格填充或字符串填充即可。例如，stackoverflow.com/questions/388461/...

答：

0赞 Senuka Liyanage 3/8/2023 #1

一个简单的方法是简单地打印出一堆空格来填充空白（填充字符串）。例如，对于输入中的最后一行，您可以执行以下操作

    System.out.print("*" + part);
    for(int i=0; i < numberOfCharacters - 2 - part.length(); i++){
        System.out.print(" ");
    }
    System.out.println("*");

这段代码所做的只是找到零件长度和理想子字符串长度之间的差值，然后打印出那么多空格。

public static void main(String[] args) {

        System.out.println("Please input a word: ");
        Scanner stringScanner = new Scanner(System.in);
        String input = stringScanner.nextLine();
        int numberOfCharacters = 20;
        System.out.println("**********************");
        for (int i = 0; i < input.length(); i += numberOfCharacters) {
            String part = input.substring(i, Math.min(input.length(), i + numberOfCharacters));
            System.out.print("*" + part);
            // Quoting the comment area answer, there should not be a minus 2 here
            for (int j = 0; j < numberOfCharacters - part.length(); j++) {
                System.out.print(" ");
            }
            System.out.println("*");
        }
        System.out.println("**********************");
    }

import java.util.Scanner;

public class NewTry {

    public static void main(String[] args) {
        System.out.println("Please input a word: ");
        Scanner stringScanner = new Scanner(System.in);
        String input = stringScanner.nextLine();
        input = input.trim();
        int numberOfCharacters = 20;
        String format = "*%-" + numberOfCharacters + "s*%n";
        System.out.println("**********************");
        int total = input.length();
        int start = 0;
        String hyphen;
        String substr;
        while (start + numberOfCharacters < total) {
            if (input.charAt(start) == ' ') {
                start++;
            }
            hyphen = "";
            int index = start + numberOfCharacters;
            if (index < total) {
                while (index > start  &&  input.charAt(index) != ' ') {
                    index--;
                }
                if (index == start) {
                    index = start + numberOfCharacters - 1;
                    hyphen = "-";
                }
            }
            substr = input.substring(start, index);
            if (substr.charAt(0) == ' ') {
                substr = substr.substring(1);
                index++;
                start++;
                int temp = start + numberOfCharacters;
                if (temp < total) {
                    if (input.charAt(temp) == ' ') {
                        index = temp;
                        substr = input.substring(start, index);
                    }
                }
            }
            System.out.printf(format, substr + hyphen);
            start = index;
        }
        if (start < total) {
            substr = input.substring(start);
            if (substr.charAt(0) == ' ') {
                substr = substr.substring(1);
            }
            System.out.printf(format, substr);
        }
        System.out.println("**********************");
        stringScanner.close();
    }
}

上面的代码假定用户输入的字符串如下：

字符串不包含标点符号，即逗号、连字符等。
字符串中的单词仅由单个空格分隔，即没有 TAB 字符或多个连续空格。

请注意，上面的代码还处理长度超过 20 个字符的单词。它通过获取 19 个字符并添加连字符来实现。

以下是我的测试运行：

Please input a word: 
George Best was a professional footballer who began his professional career playing for English football club Manchester United at the age of 17
**********************
*George Best was a   *
*professional        *
*footballer who began*
*his professional    *
*career playing for  *
*English football    *
*club Manchester     *
*United at the age of*
*17                  *
**********************

Please input a word: 
antidisestablishmentarianism
**********************
*antidisestablishmen-*
*tarianism           *
**********************

Please input a word: 
can you spell antidisestablishmentarianism
**********************
*can you spell       *
*antidisestablishmen-*
*tarianism           *
**********************

Please input a word: 
antidisestablishmentarianism is a long word
**********************
*antidisestablishmen-*
*tarianism is a long *
*word                *
**********************

Please input a word: 
please find the word antidisestablishmentarianism in the dictionary
**********************
*please find the word*
*antidisestablishmen-*
*tarianism in the    *
*dictionary          *
**********************

Please input a word: 
stackoverflow
**********************
*stackoverflow       *
**********************

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如何在 java 中将字符插入到一行的特定位置？

How to insert a character into a specific spot in a line in java?

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