java：stringbuffer的常用方法

public class stringbuffer的常用方法 {
    public static void main(String[] args) {
        StringBuffer s=new StringBuffer("lxl");
        //增
        s.append(" is");
        s.append(" studing");
        s.append(" java").append(" in the dorm");
        System.out.println(s);  //lxl is studing java in the dorm

        //删：删除【m,n）之间的内容
        StringBuffer s1=new StringBuffer("0123456789");
        s1.delete(0,3);
        System.out.println(s1); //3456789

        //改
        //replace(开始的索引,结束的索引，"替换内容")；
        StringBuilder s2=new StringBuilder("0123456789");
        s2.replace(1,4,"一二三");
        System.out.println(s2); //0一二三456789

        //查
        StringBuilder s3=new StringBuilder("01234567890");
        //查找指定的字符在字符串中首次出现的索引，找不到返回-1
        System.out.println(s3.indexOf("0")); //0
        System.out.println(s3.indexOf("5")); //5

        //插：注意：索引以后的字符会自动往后移
        StringBuffer s4=new StringBuffer("01234567890");
        s4.insert(0,"零").insert(5,"一");
        System.out.println(s4); ///零0123一4567890
    }
}

运行结果：