StringBuffer类讲解

package Main;

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
       System.out.println("--------1.添加--------");
       add();
       System.out.println("--------2.删除--------");
       remove();
       System.out.println("--------3.修改--------");
       alter();
          
    }
    public static void add() {
        StringBuffer sb=new StringBuffer();
        sb.append("abcdefg");   //在末尾追加子串
        System.out.println("append的添加结果"+sb);
        sb.insert(2, "123");     //在指定位置插入字符串
        System.out.println("insert的添加结果："+sb);
    }
    public static void remove() {
        StringBuffer sb=new StringBuffer("abcdefg");
        sb.delete(1, 5);       //在指定范围删除字符串
        System.out.println("delete的删除结果："+sb);
        sb.deleteCharAt(2);    //在指定位置删除字符
        System.out.println("deleteCharAt的删除结果："+sb);
        sb.delete(0, sb.length());    //将整个字符串清除
        System.out.println(sb);
    }
    public static void alter() {
        StringBuffer sb=new StringBuffer("abcdefg");
        sb.setCharAt(1, 'p');     //修改指定位置的字符
        System.out.println("setCharAt修改指定字符的结果："+sb);
        sb.replace(1, 3, "qq");   //替换指定位置的字符或者字符串
        System.out.println("replace替换字符串的结果："+sb);
        System.out.println("reverse逆序字符串的结果："+sb.reverse());
    }
}