请问用JAVA程序 统计一个字符串中出现某个字母的次数

Question

如题所述

Answer 1

public static void main(String[] args) {String a="ajkjdjljeojkajdljcs";String b="a";int c=0;for(int i=0;i<a.length();i++)if(b.equles(a.substring(i)))c++;system.out.println(b+"的个数是"+c)}

Answer 2

http://www.cnblogs.com/pochonlee/archive/2008/01/07/949007.html#1028783
不仅仅能统计字母，还有单词。如果字母，把正则表达式改为字母就可以。

Answer 3

//看看吧。。。
import java.util.Vector;

import javax.swing.JOptionPane;

public class Test {
public static void main(String[] args) {
Vector v = new Vector();
boolean fo = true;
String string = JOptionPane.showInputDialog("输出参数");
for (int i = 0; i < string.length(); i++) {
if (v.size() == 0) {
javaBean jb = new javaBean();
jb.setCa(string.charAt(i));
jb.setA(1);
v.add(jb);
fo = false;
} else {
for (int count = 0; count < v.size(); count++) {
javaBean jb = (javaBean) v.get(count);
if (string.charAt(i) == jb.getCa()) {
jb.setA(jb.getA() + 1);
v.set(count, jb);
fo = false;
break;
}
}
}
if (fo) {
javaBean jb = new javaBean();
jb.setCa(string.charAt(i));
jb.setA(1);
v.add(jb);
}
fo = true;
}
String s = "你输入的参数是：";
for (int count = 0; count < v.size(); count++) {
if(count%4==0){
s+="\n";
}
javaBean jb = (javaBean) v.get(count);
s += jb.getCa() + "有" + jb.getA()+"个 ";
}
JOptionPane.showMessageDialog(null, s);
}

}

class javaBean {
char ca;

int a = 0;

public int getA() {
return a;
}

public void setA(int a) {
this.a = a;
}

public char getCa() {
return ca;
}

public void setCa(char ca) {
this.ca = ca;
}

}