我如何操作这个字符串，以便在Java中查找和更改原始字符串的一部分？

public class StringReplaceExample {
    public static void main(String[] args) {
        // 原始字符串
        String originalString = "Hello, World!";

        // 要查找的部分
        String searchString = "World";

        // 替换后的部分
        String replacementString = "Java";

        // 查找并替换字符串
        String newString = originalString.replace(searchString, replacementString);

        // 输出结果
        System.out.println("Original String: " + originalString);
        System.out.println("New String: " + newString);
    }
}

Original String: Hello, World!
New String: Hello, Java!

// 只替换第一次出现的子字符串
String newStringFirstOnly = originalString.replaceFirst(searchString, replacementString);

// 使用正则表达式替换所有匹配的部分
String regex = "o"; // 查找所有的'o'
String newStringRegex = originalString.replaceAll(regex, "a"); // 替换为'a'

System.out.println("Replace First Only: " + newStringFirstOnly);
System.out.println("Replace Using Regex: " + newStringRegex);

Replace First Only: Hell, World!
Replace Using Regex: Hella, Warld!

StringBuilder stringBuilder = new StringBuilder(originalString);
int index = stringBuilder.indexOf(searchString);
if (index != -1) {
    stringBuilder.replace(index, index + searchString.length(), replacementString);
}
String newStringBuilderString = stringBuilder.toString();

System.out.println("Using StringBuilder: " + newStringBuilderString);

Using StringBuilder: Hello, Java!