求两个字符串的最长公共子串

    public static String findLongestOfTheSame(String s1,String s2) {
        char[] c1=s1.toCharArray();
        char[] c2=s2.toCharArray();
        int l1=c1.length;
        int l2=c2.length;
        int count=0,maxLength=0,start=0,end=0;
        boolean hasTheSame=false;
        for(int i=0;i<l1;i++)
        {
            count=0;
            for(int j=0;j<l2;j++)
            {
                if(c1[i]==c2[j])
                {
                    hasTheSame=true;
                    do
                    {
                        count++;
                        if(count>maxLength)
                        {
                            maxLength=count;
                            start=i;
                            end=i+count;
                        }
                    }while(i+count<l1 && j+count<l2 && c1[i+count]==c2[j+count]);
                    count=0;
                }
            }
        }
        return new String(hasTheSame?Arrays.copyOfRange(c1, start, end):null);
    }