字符串方法通过带计数的参数进行整数运算

Question

我需要编写一个静态方法，它接受一个String并返回一个整数。然后，返回字母"e"出现在传入的String类型的方法参数中的次数。

import java.util.Scanner;
public class Main{
public static void main(String []args){
Scanner scan = new Scanner(System.in)
System.out.println("Input text for how many 'e's are inside")
String e = scan.nextLine();
}
}

所以我有输入，但我不知道如何将其作为一个参数，并返回在字符串中找到字母"e"的次数。

Answer 1

有一个很好的愿望，就是用Java流来实现这一点，

public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.println("Input text for how many 'e's are inside");
String e = scan.nextLine();
long count = countCharacter(e);
System.out.println(count);
}
private static long countCharacter(String string) {
char[] chars = string.toCharArray();
return IntStream.range(0, chars.length)
.mapToObj(i -> chars[i])
.filter(c -> c == 'e')
.count();
}

Answer 2

public class Sample {
public static void main(String[] args) {
java.util.Scanner input = new java.util.Scanner(System.in);
String entry = input.nextLine();
System.out.println(countE(entry)); // Call to function
}
// Occurrence of E counter function
public static int countE (String input) {
int occurence = 0;
for (int index = 0; index < input.length(); index++) {
if (input.charAt(index) == 'e')
occurence++;
}
return occurence;
}
}