stringbuffer类的构造方法

public class demo_stringbuffer {
public static void main(String[] args) {
StringBuffer sb = new StringBuffer();//空参构造
System.out.println(sb.length());// 容器中的字符个数，实际值
System.out.println(sb.capacity());// 容器的初始容量，理论值
StringBuffer sb1 = new StringBuffer(10);//有参构造
System.out.println(sb1.length());
System.out.println(sb1.capacity());
StringBuffer sb2 = new StringBuffer("wf");//有参构造
System.out.println(sb2.length());// 实际字符的个数
System.out.println(sb2.capacity());// 字符串的lengh+初始容量
}

}