生成随机字符的类，并统计字符个数的方法JAVA

class RandomCharacter

代码：

public class RandomCharacter {
	public static char getRandomCharacter(char ch1,char ch2){
		return (char)(ch1+Math.random()*(ch2-ch1+1));
	}
		
	public static char getRandomLowerCaseLetter(){
		return getRandomCharacter('a','z');
	}
	
	public static char getRandomUpperCaseLetter(){
		return getRandomCharacter('A','Z');	
	}
	
	public static char getRandomDigitCharacter(){
		return getRandomCharacter('0','9');
	}
	
	public static char getRandomCharacter(){
		return getRandomCharacter('\u0000','\uFFFF');
	}
}

public class RandomCharacter {

public static char getRandomCharacter(char ch1,char ch2){

return (char)(ch1+Math.random()*(ch2-ch1+1));

}

public static char getRandomLowerCaseLetter(){

return getRandomCharacter('a','z');

}

public static char getRandomUpperCaseLetter(){

return getRandomCharacter('A','Z');

}

public static char getRandomDigitCharacter(){

return getRandomCharacter('0','9');

}

public static char getRandomCharacter(){

return getRandomCharacter('\u0000','\uFFFF');

}

class CountLettersInArray

public class CountLettersInArray {
	public static void main(String[] args){
		char[] chars=createArray();
		System.out.println("The lowercase letters are:");
		displayArray(chars);
		int[] counts=countLetters(chars);
		System.out.println();
		System.out.println("The occurrences of each letter are:");
		displayCounts(counts);
	}
	
	public static char[] createArray(){
		char[] chars=new char[100];
		for(int i=0;i<chars.length;i++)
			chars[i]=RandomCharacter.getRandomLowerCaseLetter();
		return chars;
	}
	
	public static void displayArray(char[] chars){
		for(int i=0;i<chars.length;i++){
			if((i+1)%20==0)
				System.out.println(chars[i]+" ");
			else
				System.out.print(chars[i]+" ");
		}
	}
	
	public static int[] countLetters(char[] chars){
		int[] counts=new int[26];
		for(int i=0;i<chars.length;i++)
			counts[chars[i]-'a']++;
		return counts;
	}
	
	public static void displayCounts(int[] counts){
		for(int i=0;i<counts.length;i++){
			if((i+1)%10==0)
				System.out.println(counts[i]+" "+(char)(i+'a'));
			else
				System.out.println(counts[i]+" "+(char)(i+'a')+" ");
		}
	}
}