Java中StringBuilder用法

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

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);
    }
}