java - 如何在子字符串之前和之后打印字符串，然后将新字符串添加到旧字符串中？

Question

我正在尝试制作一个程序，可以读取子字符串之前和之后的字符串，然后要求用户添加新字符串并打印新字符串，用户喜欢的位置是一个示例:

Enter a long string: The quick brown fox jumped over the lazy dog

Enter a substring: jumped

Length of your string: 44

Length of your substring: 6

Starting position of your substring in string: 20

String before your substring: The quick brown fox

String after your substring:  over the lazy dog

Enter a position between 0 and 43: 18

The character at position 18 is x

Enter a replacement string: leaped

Your new string is: The quick brown fox leaped over the lazy dog

这是我正在执行的代码:

import java.util.Scanner;

public class Project02 {

    public static void main(String[] args) {

        Scanner name = new Scanner (System.in);

        System.out.println("Enter a long string: ");
        String username = name.nextLine();
        System.out.println("Enter a substring: ");
        String subname = name.nextLine();
        System.out.println("Length of your string: "+ username.length());
        System.out.println("Length of your substring: " + subname.length());
        System.out.println( "Starting position of your substring in string: "+ username.indexOf(subname));

        System.out.println("Enter a replacement string: ");
        String newname = name.nextLine();
        System.out.println("Your new string is: "+ );


    }

}

Answer 1

所以:

int index = text.indexOf(substring);
String left = text.substring(0, index);
String right = text.substring(index + substring.length());
String replacement = name.nextLine();
String newText = left + replacement + right;