Java 如何确定何时到达文件末尾？
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How to determine when end of file has been reached?
提问by Blackbinary
I am trying to read text from a text file. I need help figuring out when the end of file has occured. How can I determine this in Java?
我正在尝试从文本文件中读取文本。我需要帮助弄清楚文件何时结束。我如何在 Java 中确定这一点？
FileInputStream istream = new FileInputStream("\""+filename+"\"");
Scanner input = new Scanner(istream);
while(EOF != true)
{
....
}
Thanks!
谢谢！
回答by jjnguy
You can check using hasNextLine():
您可以使用hasNextLine()以下方法检查：
Scanner input = new Scanner(new File("\""+filename+"\""));
while(input.hasNextLine())
{
String data = input.nextLine();
}
回答by Thomas Langston
Line based retrieval may be what you want, but token based can also be useful.
You can see in documentation of Scanner
基于行的检索可能是您想要的，但基于令牌的检索也很有用。你可以在文档中看到Scanner
public boolean hasNext()
Returns
trueif thisScannerhas another token in its input. This method may block while waiting for input to scan. TheScannerdoes not advance past any input.Specified by:
hasNextin interfaceIterator<String>Returns:
trueif and only if thisScannerhas another tokenThrows:
IllegalStateException- if thisScanneris closedSee Also:
Iterator
返回它的输入中
true是否Scanner有另一个标记。此方法可能会在等待输入扫描时阻塞。在Scanner不执行任何输入。指定者：
hasNext在接口中Iterator<String>返回：
true当且仅当它Scanner有另一个令牌抛出：
IllegalStateException- 如果这Scanner是关闭的也可以看看：
Iterator
