java中stringbuilder和stringbuffer,Java stringbuilder

StringBuilder我们可以把其看成一个容器，是一个可变的字符串类，其StringBuilder对象中的内容是可变的

StringStringBuilderString中的内容不可变StringBuilder:内容是可变的StringBuilder通过append方法不断添加字符串到该容器中package Socket_Thread.StringBuilderDemo;/** * @Author: 从南到北 * @Date: 2021/12/31/10:34 */public class StringBuilderDemo01 { public static void main(String[] args) { StringBuilder sb = new StringBuilder(); System.out.println("sb:"+sb); System.out.println("sb.length:"+sb.length()); StringBuilder sb2 = new StringBuilder("hello"); System.out.println("sb2:"+sb2); System.out.println("sb2的长度："+sb2.length()); }}

StringBuilder中有两个常用的方法

append
任意类型要圈住，很重要

package Socket_Thread.StringBuilderDemo;/** * @Author: 从南到北 * @Date: 2021/12/31/10:34 */public class StringBuilderDemo01 { public static void main(String[] args) { StringBuilder sb = new StringBuilder(); sb.append("hello"); sb.append("world"); sb.append("100"); System.out.println("sb:"+sb); }}

package Socket_Thread.StringBuilderDemo;/** * @Author: 从南到北 * @Date: 2021/12/31/10:34 */public class StringBuilderDemo01 { public static void main(String[] args) { //创建对象 StringBuilder sb = new StringBuilder(); //因为append方法返回的是对象本身，对象就可以调方法，所以，可以一直调用方法，即链式编程 //链式编程 sb.append("hello").append("world").append("java").append(100); System.out.println("sb:" + sb); //public StringBuilder reverse()：返回相反的字符序列，直接把内容反转 sb.reverse(); System.out.println("sb:" + sb); }}