StringBuffer中delete(x, y) 删除左闭右开区间的元素，append() 函数用于连接字符串。

package com.czie.iot1913.lps.genericityDemo.Demo03;

/**
 * @author 1944900433@qq.com
 * @date 2022-03-19 21:50
 */
public class Test {

    public static void main(String[] args) {
        StringBuffer a = new StringBuffer("JavaYYDS");
        StringBuffer b = new StringBuffer("Google");
        a.delete(1, 3);
        a.append(b);
        System.out.println(a);
    }
}