Java object-oriented - common classes - String&StringBuilder&StringBuffer class

Programming requirements
Please read the code on the right carefully and follow the prompts in the method to supplement the code in the Begin-End area. The specific tasks are as follows:

Write a test class, input a standard URL, and output the subject of its domain name;

Convert the body to uppercase and print the output;

Please see the test instructions for specific output requirements.

package case3;

import java.util.Scanner;

public class StringTest {
    
    
	public static void main(String[] args) {
    
    
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
		// String substring(int start,int end)
        // 截取字符串，传入的两个参数分别为要截取边界的下标
        // 在java api 中,通常使用两个数字表示范围时,都是含头不含尾,即包含起始下标对应的内容,但不包含结束下标的处对应的内容
        // String toUpperCase() 将当前字符串中的英文部分转换为全大写
		/********* Begin *********/
        String str1 = str.substring(12,str.lastIndexOf('.'));
        if(str1.indexOf('.')>0){
    
    
            str1 = str1.substring(0,str1.indexOf('.'));
        }
        System.out.println(str1);
        str1 = str1.toUpperCase();
        System.out.println(str1);

		/********* End *********/
	}
}