我無法理解的StringBuilder的以下行爲時,NULL對象被附加到一個實例:爲NULL StringBuffer的行爲對象
public class StringBufferTest {
/**
* @param args
*/
public static void main(String[] args) {
String nullOb = null;
StringBuilder lsb = new StringBuilder();
lsb.append("Hello World");
System.out.println("Length is: " + lsb.length());// Prints 11. Correct
lsb.setLength(0);
System.out.println("Before assigning null" + lsb.length());
lsb.append(nullOb);
System.out.println("Length now is:" + lsb.length()); // Prints 4. ???
}
}
最後一個print語句不打印0誰能請幫助我理解行爲?
D *** shoud已閱讀append(String)的文檔。謝謝 !! –