使用\ Z vs \ z作为扫描仪分隔符的行为 [英] Behavior of using \Z vs \z as Scanner delimiter
问题描述
我找到了答案,但由于新用户的限制,我无法回答这个问题。无论哪种方式,这都是Java中的已知错误。
http://bugs.java.com/bugdatabase/view_bug.do?bug_id=8028387
我正在尝试在64位ubuntu上将文件读入Java 6中的字符串。 Java给了我一个非常奇怪的结果,用\\Z
它读取整个文件,但是用\\z
它会读取最多1024个字符的整个字符串。我已经阅读了所有类的Java 6 API,但我很茫然。
\ Z和\z的说明可以在以下位置找到:
http://docs.oracle.com/javase/6/docs/api/java/util/regex/Pattern.html#lt
<什么可能导致这种奇怪的行为?
String fileString = new Scanner(new File(fileName))。useDelimiter(\\\\)。next( );
String fileString2 = new Scanner(new File(fileName))。useDelimiter(\\Z)。next();
System.out.println(使用Z:+ fileString2.length());
System.out.println(Using z+ fileString.length());
输出:
使用Z:9720
使用z:1024
谢谢!
有关文件/ java版本的详细信息:
使用java-6-openjdk-amd64运行Ubuntu(也使用oracle java6测试)
文件是简单的文本文件UTF-8编码。
模式文档状态
-
\ z
输入结束 -
\ Z
输入结束但最终终止符(如果有)
我怀疑是因为扫描仪缓冲区大小设置为 1024 ,
354 私人 静态 最终 int BUFFER_SIZE = 1024; //更改为1024;
扫描程序读取此数量的字符并将其用作当前输入,因此 \ z
可以在这里用来表示它的结束,而 \Z
不能,因为它不是最终终结者(还有更多的元素)在整个输入中阅读)。
[Edit] I found the answer, but I can't answer the question due to restrictions on new users. Either way, this is a known bug in Java.
http://bugs.java.com/bugdatabase/view_bug.do?bug_id=8028387
I'm trying to read a file into a string in Java 6 on 64 bit ubuntu. Java is giving me the very strange result that with "\\Z"
it reads the entire file, but with "\\z"
it reads the entire string up to 1024 characters. I've read the Java 6 API for all the classes and I am at a loss.
Description of \Z and \z can be found at:
http://docs.oracle.com/javase/6/docs/api/java/util/regex/Pattern.html#lt
What could be causing this strange behavior?
String fileString = new Scanner(new File(fileName)).useDelimiter("\\z").next();
String fileString2 = new Scanner(new File(fileName)).useDelimiter("\\Z").next();
System.out.println("using Z : " + fileString2.length());
System.out.println("Using z "+ fileString.length());
Output: using Z : 9720 Using z : 1024
Thanks!
Details about the file/java-version:
Running Ubuntu with java-6-openjdk-amd64 (tested also with oracle java6) File is simple text file UTF-8 encoded.
As Pattern documentation states
\z
The end of the input\Z
The end of the input but for the final terminator, if any
I suspect that since Scanners buffer size is set to 1024,
354 private static final int BUFFER_SIZE = 1024; // change to 1024;
Scanner reads this amount of characters and uses it as current input, so \z
can be used here to represent its end, while \Z
can't because it is not "final terminator" (there are more elements in entire input to read).
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