java实现求两个字符串最长公共子串的方法

import java.util.Scanner;public class Main { public static void main(String[] args) {  Scanner sc = new Scanner(System.in);  Main mainObj = new Main();  int len = mainObj.getCommonStrLength(sc.next(),sc.next());  System.out.println(len); } int getCommonStrLength(String str1, String str2) {   str1 = str1.toLowerCase();    str2 = str2.toLowerCase();    int len1 = str1.length();    int len2 = str2.length();    String min = null;    String max = null;    String target = null;   min = len1 <= len2 ? str1 : str2;   max = len1 > len2 ? str1 : str2;   //最外层：min子串的长度，从最大长度开始   for (int i = min.length(); i >= 1; i--) {    //遍历长度为i的min子串，从0开始    for (int j = 0; j <= min.length() - i; j++) {      target = min.substring(j, j + i);      //遍历长度为i的max子串，判断是否与target子串相同，从0开始     for (int k = 0; k <= max.length() - i; k++) {       if (max.substring(k,k + i).equals(target)) {        return i;       }     }    }   }    return 0;  }}