字符串的拼接

package hu;

public class StringBuffer1 {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
StringBuffer sb =new  StringBuffer();
sb.append("a1");
sb.append("a1");
sb.append("a1");
sb.append("a1");
System.out.println(sb.toString());
System.out.println(sb.capacity());//默认值为16
System.out.println(sb.length());

}

}