Java反转字符串的五种方法总结

public class ReverseStringWithStringBuilder {
    public static void main(String[] args) {
        String original = "Hello, World!";
        StringBuilder sb = new StringBuilder(original);
        sb.reverse();
        String reversed = sb.toString();
        System.out.println(reversed); // 输出: "!dlroW ,olleH"
    }
}

public class ReverseStringWithCharArray {
    public static void main(String[] args) {
        String original = "Hello, World!";
        char[] charArray = original.toCharArray();
        int left = 0;
        int right = charArray.length - 1;

        while (left < right) {
            char temp = charArray[left];
            charArray[left] = charArray[right];
            charArray[right] = temp;

            left++;
            right--;
        }

        String reversed = new String(charArray);
        System.out.println(reversed); // 输出: "!dlroW ,olleH"
    }
}

public class ReverseStringWithCustomStringBuilderMethod {
    public static void reverse(StringBuilder sb, int left, int right) {
        while (left < right) {
            char tmp = sb.charAt(left);
            sb.setCharAt(left++, sb.charAt(right));
            sb.setCharAt(right--, tmp);
        }
    }

    public static void main(String[] args) {
        String original = "Hello, World!";
        StringBuilder sb = new StringBuilder(original);
        reverse(sb, 0, sb.length() - 1);
        String reversed = sb.toString();
        System.out.println(reversed); // 输出: "!dlroW ,olleH"
    }
}

public class StringReversal {  
  
    public static void reverseString(char[] s) {  
        int l = 0;  
        int r = s.length - 1;  
        while (l < r) {  
            char temp = s[l];  
            s[l] = s[r];  
            s[r] = temp;  
            l++;  
            r--;  
        }  
    }  
  
    public static void main(String[] args) {  
        char[] str = "Hello, World!".toCharArray();  
        reverseString(str);  
        System.out.println(new String(str)); // 输出: "!dlroW ,olleH"  
    }  
}

import java.util.stream.Collectors;

public class ReverseStringWithStream {
    public static void main(String[] args) {
        String original = "Hello, World!";
        String reversed = original.chars() // 将字符串转换为int流
                                .mapToObj(c -> (char) c) // 将int流转换为Character对象流
                                .collect(Collectors.toList()) // 收集到List中
                                .stream() // 再将List转换回流
                                .reduce(new StringBuilder(), StringBuilder::append, StringBuilder::append) // 使用reduce和StringBuilder来拼接字符串
                                .reverse() // 反转StringBuilder中的字符串
                                .toString(); // 将StringBuilder转换为String

        System.out.println(reversed); // 输出: "!dlroW ,olleH"
    }
}