java - StringIndexOutOfBound 异常

Question

我试图编写一个程序，它从用户那里获取一个字符串，并告诉用户该字符串中小写字母、大写字母、空格等的数量。但我收到一条错误消息:StringIndexOutOfBound。

public class CharacterCount {
    public static void main(String args[])throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Please enter you string here");
        String s = br.readLine();
        System.out.println(s);

        int upperCase = 0;
        int lowerCase = 0;
        int specialCase = 0;
        int whiteSpace = 0;
        int number = 0;

        for(int i=1;i<=s.length();i++)
        {
            char ch = s.charAt(i);
            if(Character.isAlphabetic(ch))
            {
                if(Character.isUpperCase(ch))
                {
                    upperCase++;
                }
                else
                {
                    lowerCase++;
                }
            }

            if(Character.isWhitespace(ch))
            {
                whiteSpace++;
            }
            if(Character.isDigit(ch))
            {
                number++;
            }
            else
            {
                specialCase++;
            }
        }

        System.out.println("-----------------------------------------------------------------");
        System.out.println("The following are the results:");
        System.out.println("-----------------------------------------------------------------");
        System.out.println(lowerCase+" :Lower Case Characters");
        System.out.println("-----------------------------------------------------------------");
        System.out.println(upperCase+" :Upper Case Characters");
        System.out.println("-----------------------------------------------------------------");
        System.out.println(whiteSpace+" :White Space");
        System.out.println("-----------------------------------------------------------------");
        System.out.println(specialCase+" :Special Characters");
        System.out.println("-----------------------------------------------------------------");
        System.out.println(number+" :Digits");
        System.out.println("-----------------------------------------------------------------");
        System.out.println("----------------************THE END************------------------");
        System.out.println("-----------------------------------------------------------------");

    }
}

Answer 1

您正在迭代错误的索引。 Java 索引从 0 开始，因此 length() 字符的字符串具有从 0 到 length()-1 的索引。

你的循环应该是

for(int i=0;i<s.length();i++)