java获取两个字符串中最大相同字串

import static java.lang.System.*;

/**
 * @Date:CreatedIn 2020/6/29 19:56
 * @Description:获取两个字符串中最大相同字串。
 */
public class Test {
    public static void main(String[] args) {
        String str1 = "abcwerthelloyuiodef";
        String str2 = "cvhellobnm";
        Test t = new Test();
        String str = t.sameStr(str1,str2);
        out.println(str);
    }

    public String sameStr(String str1,String str2) {
        if (str1.isEmpty() || str2.isEmpty()) {
            return null;
        }
        String maxStr = str1.length() >= str2.length() ? str1 : str2;
        String minStr = str1.length() < str2.length() ? str1 : str2;
        int length = minStr.length();
        for (int i = 0; i < length; i++) {
            for (int x = 0, y = length - i; y <= length; x++, y++) {
                String subStr = minStr.substring(x, y);
                if (maxStr.contains(subStr)) {
                    return subStr;
                }
            }
        }
        return null;
    }
}