如何在 Java 中为分隔符指定多种模式
所以我有一种方法可以使用删除“null(U)”引用的分隔符将一个文件复制到另一个文件，并且输入文件看起来像...
C:\Documents and Settings\workspace\Extracted Items\image2.jpeg;image0;null(U) keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image3.jpeg;image1;null(U) keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image4.jpeg;image2;null(U) keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image5.jpeg;image3;null keyword1, keyword2, keyword3, keyword4,
...输出文件看起来像...
C:\Documents and Settings\workspace\Extracted Items\image2.jpeg;image0;keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image3.jpeg;image1;keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image4.jpeg;image2;keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image5.jpeg;image3;null keyword1, keyword2, keyword3, keyword4,
并且对于关于我的分隔符的一小块代码，我有......
Scanner reader = new Scanner(inputFile);
reader.useDelimiter("null\\(U\\) ");
但是，我想知道，如果我想指定分隔符应该查找的多个模式（即除了“null（U）”之外，我想添加“null”），我该怎么做呢？我在网上看到了一些例子，但我仍然不确定分隔符如何区分各种模式。非常感谢任何建议！
so I have a method that copies one file to another with the use of a delimiter that removes the "null(U)" references, and the input file looks like...
C:\Documents and Settings\workspace\Extracted Items\image2.jpeg;image0;null(U) keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image3.jpeg;image1;null(U) keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image4.jpeg;image2;null(U) keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image5.jpeg;image3;null keyword1, keyword2, keyword3, keyword4,
...and the output file looks like...
C:\Documents and Settings\workspace\Extracted Items\image2.jpeg;image0;keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image3.jpeg;image1;keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image4.jpeg;image2;keyword1, keyword2, keyword3, keyword4,
C:\Documents and Settings\workspace\Extracted Items\image5.jpeg;image3;null keyword1, keyword2, keyword3, keyword4,
And for the small chunk of code regarding my delimiter, I have...
Scanner reader = new Scanner(inputFile);
reader.useDelimiter("null\\(U\\) ");
However, I was wondering, if I wanted to specify multiple patterns which the delimiter should look for (i.e. in addition to "null (U)", I wanted to add "null"), how would I go about doing that? I've seen a few examples online, but I'm still not sure how the delimiter is able to distinguish between the various patterns. Any advice is greatly appreciated!
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您可以使用正则表达式并创建一个类似于 : 的模式
，然后将该模式提供给
useDelimiter(p)方法。正则表达式可能类似于
(null\\s)|(null\\(U\\)\\s)You could use a regex and create a pattern with something like :
and then give that pattern to the
useDelimiter(p)method.The regex could be something like
(null\\s)|(null\\(U\\)\\s)