Java 检查 StringBuffer 是否为空
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Check if StringBuffer is empty
提问by Aman Shukla
Can anyone please tell me how I can use if-else condition with StringBuffer to check if it is empty?
谁能告诉我如何使用带有 StringBuffer 的 if-else 条件来检查它是否为空？
I am expecting something like this
我期待这样的事情
if (Stringbuffer is empty){
// some condition
}
else {
// some other condition
}
回答by Andy Turner
[returns] the length of the sequence of characters currently represented by this object
[返回] 此对象当前表示的字符序列的长度
so you can use the fact that StringBuffer.length()returns zero (or not) to check if the buffer is empty (or not).
因此您可以使用StringBuffer.length()返回零（或不返回）的事实来检查缓冲区是否为空（或不为空）。
Note that you should probably be using StringBuilderinstead of StringBuffer. From the Javadoc of StringBuffer:
请注意，您可能应该使用StringBuilder而不是StringBuffer. 来自Javadoc 的StringBuffer：
As of release JDK 5, this class has been supplemented with an equivalent class designed for use by a single thread,
StringBuilder. TheStringBuilderclass should generally be used in preference to this one, as it supports all of the same operations but it is faster, as it performs no synchronization.
从 JDK 5 版本开始，这个类已经补充了一个设计用于单线程的等效类，
StringBuilder. 所述StringBuilder类通常应优先使用这一个，因为它支持所有相同的操作，但它是快的，因为它不执行同步。
