如何取string字符中有几个相同的字符&&如何把两个字符串中相同的字符赛选出来

如何取string字符中有几个相同的字符串&&如何把两个字符串中相同的字符串赛选出来

package springboot02configautoconfig;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class cs {
        public static void main(String[] args){
            String s1 = "AABBC";
            String s2 = "ABBCC";
            String s3 =  "AABCC";
            Integer A = 0;
            List<String> sub1 = new ArrayList<String>();//保存s1的子串
            List<String> sub2 = new ArrayList<String>();//保存s2的子串
            List<String> sub3 = new ArrayList<String>();//保存s3的子串
            Set<String> result = new HashSet<String>();//保存相同的子串
//求s1的子串
            for(int i = 1;i<s1.length();i++){
                for(int j = 0;j<=s1.length()-i;j++){
                    sub1.add(s1.substring(j,j+i));
                }
            }
//求s2的子串
            for(int i = 1;i<s2.length();i++){
                for(int j = 0;j<=s2.length()-i;j++){
                    sub2.add(s2.substring(j,j+i));
                }
            }
            for(int i = 1;i<s3.length();i++){
                for(int j = 0;j<=s3.length()-i;j++){
                    sub3.add(s3.substring(j,j+i));
                }
            }
            System.out.println("\"AABBC\"的子串 ： " + sub1);
            System.out.println("\"ABBCC\"的子串 ： " + sub2);
            System.out.println("\"ABBCC\"的子串 ： " + sub3);
            for(int o = 0; o<s1.length();o++) {
                if(s1.charAt(o)=='A'){
                    A++;
                }
            }
            System.out.println(A);
            for(String s: sub1)
                if(sub2.contains(s)&&sub3.contains(s))
                    result.add(s);
            for(String s: sub2)
                if(sub1.contains(s)&&sub3.contains(s))
                    result.add(s);
            for(String s: sub3)
                if(sub2.contains(s)&&sub1.contains(s))
                    result.add(s);
            System.out.println("相同的子串 ： " + result);
        }
    }