请问stringBuffer的问题?stringBuffer.append(null)???
卡纳瓦咯 2006-07-19 05:37:17 package other;
public class A {
public static void main(String[] args) {
String str1 = "aa";
if(str1.equalsIgnoreCase("aa")) {
str1 = null;
}
StringBuffer str = new StringBuffer();
str.append("aa").append(str1);//这里str1=null,好用
System.out.println(str.toString());
}
}
输出结果是aanull
为什么str在调用append的时候参数是null,他却当成字符串处理了?
但是,
package other;
public class A {
public static void main(String[] args) {
str1 = null;
StringBuffer str = new StringBuffer();
str.append("aa").append(str1);//null,编译出错
System.out.println(str.toString());
}
}
请问这是为什么?