differ比较两个字符串的差异

"abcde","abdefk"  ---->-c,+f,+k

"aba","aababb"    ----->+a,+b,+b

 import java.util.ArrayList;

 public class differ {

     public static void main(String[] args) {
         System.out.println(differ("abcde","abdefk"));
         System.out.println(differ("aba","aababb"));
     }
     public static String differ(String a,String b)
     {
         String plus="";
         String neg="";
         ArrayList arr=new ArrayList();
         for(int i=0;i<a.length();i++)
         {
             arr.add(a.charAt(i));
         }
         for(int j=0;j<b.length();j++)
         {
             if(arr.indexOf(b.charAt(j))!=-1)
                 arr.remove(arr.indexOf(b.charAt(j)));//说明有
             else
                 plus+=",+"+b.charAt(j);
         }
         for(int i=0;i<arr.size();i++)
             neg+="-"+arr.get(i);
         if(neg=="")
             plus=plus.substring(1);//去掉逗号
         return neg+plus;
     }

 }

结果: