我正在嘗試找到使用不同塊用法的最佳性能方式/方法。我正在運(yùn)行下面的回文程序，用 3 種不同的方式測(cè)量每個(gè)程序的執(zhí)行時(shí)間。但我總是得到'0'作為輸出。我的代碼有什么問(wèn)題。請(qǐng)幫我。主要的    long startTime, endTime, duration;    startTime = Instant.now().toEpochMilli();    System.out.println(palindromeUsingStringBuilderReverse(str));    endTime = Instant.now().toEpochMilli();    duration = (endTime - startTime);    System.out.println("Duration for using string builder : " + duration);    startTime = Instant.now().toEpochMilli();    System.out.println(palindromeUsingForLoop(str));    endTime = Instant.now().toEpochMilli();    duration = (endTime - startTime);    System.out.println("Duration for using for loop : " + duration);    startTime = Instant.now().toEpochMilli();    System.out.println(palindromeUsingWhile(str));    endTime = Instant.now().toEpochMilli();    duration = (endTime - startTime);    System.out.println("Duration for using while loop : " + duration);回文使用 StringBuilderReverseStringBuilder bdr = new StringBuilder(str);        if (str.equalsIgnoreCase(bdr.reverse().toString())) {            return "The given string is a Palindrome.";        } else {            return "This is not a Palindrome string.";        }回文使用ForLoopString revStr = "";for (int i=str.length()-1; i>=0; i--) {                revStr = revStr + str.charAt(i);                }    if (str.equalsIgnoreCase(revStr)) {                return "The given string is a Palindrome.";            } else {                return "This is not a Palindrome string.";            }回文UsingWhile    int i = 0, j = str.length() - 1;    while (i < str.length()) {        if (str.charAt(i) != str.charAt(j)) {            return "This is not a Palindrome string.";        } else {            i++;            j--;        }    }    return "The given string is a Palindrome.";