java常见面试题

经典题解：//package com.shy.bean;
1.字符排序
public class This{
static void strings(String s){
char[] s1=s.toCharArray();
String ABC="";
String abc="";
String _123="";
String others="";
for(int c=0;c<s1.length;c++){
if((int)s1[c]>=48&(int)s1[c]<=57){
_123=s1[c]+_123;
}else if((int)s1[c]>=65&(int)s1[c]<=90){
ABC=ABC+s1[c];
}else if((int)s1[c]>=97&(int)s1[c]<=122){
abc=abc+s1[c];
}else{
others=others+s1[c];
}
}
System.out.println(abc+ABC+_123+others);

}
public static void main(String[] args) {
This.strings("*&^%$#@!123A12aaaaERERR");
}}
2.判断一个数是否是质数
public class zhishu{
static int a = 2;
public static void main(String[] args) {