Comments require reader.markSupported() to return true beanio

huangapple
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英文:

Comments require reader.markSupported() to return true beanio

问题

以下是翻译好的内容：

  1. Xml文件
  3. <beanio xmlns="http://www.beanio.org/2012/03"
  4.                 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  5.                 xsi:schemaLocation="http://www.beanio.org/2012/03 http://www.beanio.org/2012/03/mapping.xsd">
  6.     
  7.             <stream name="stream" format="delimited" ignoreUnidentifiedRecords="true">
  8.                 <parser>
  9.                     <property name="delimiter" value="|"/>
  10.                     <property name="comments" value="Response Codes:,|File Trailer|,File Header|"/>
  11.                 </parser>
  12.     
  13.     			<group name="HeaderRecord">
  14.     				<record>
  15.     				.
  16.     				.
  17.     				.
  18.     				</record>
  19.     			</group>
  20.     			<group name="GroupHeader">
  21.     			    <record>
  22.     				.
  23.     				.
  24.     				.
  25.     				.
  26.     				</record>
  27.     			</group>
  28.     		</stream>
  29.     </beanio>
  31. 包含记录的文件如下所示
  33.     1   File Header|
  34.     .   HeaderRecord文本.....
  35.     .   GroupHeader文本......
  36.     19  Response Codes:
  37.     20                 |A - StackOverflow           |                
  38.     21                 |B - Facebook                |               
  39.     22                 |C - Google                  |                
  40.     23  |File Trailer|
  43. 错误
  44. java.lang.IllegalArgumentException: 评论需要reader.markSupported()返回true
  45.     	at org.beanio.stream.util.CommentReader.<init>(CommentReader.java:61)
  46.     	at org.beanio.stream.delimited.DelimitedReader.<init>(DelimitedReader.java:149)
  47.     	at org.beanio.stream.delimited.DelimitedRecordParserFactory.createReader(DelimitedRecordParserFactory.java:56)
  48.     	at org.beanio.internal.parser.StreamFormatSupport.createRecordReader(StreamFormatSupport.java:61)
  49.     	at org.beanio.internal.parser.Stream.createBeanReader(Stream.java:88)
  51. 我想忽略文件头，尾部和响应代码。响应代码从下一行开始。各种博客建议在属性中使用评论。有人能解释为什么不起作用吗？
英文:

Xml File

  1. <beanio xmlns="http://www.beanio.org/2012/03"
  2.             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  3.             xsi:schemaLocation="http://www.beanio.org/2012/03 http://www.beanio.org/2012/03/mapping.xsd">
  5.         <stream name="stream" format="delimited" ignoreUnidentifiedRecords="true">
  6.             <parser>
  7.                 <property name="delimiter" value="|"/>
  8.                 <property name="comments" value="Response Codes:,|File Trailer|,File Header|"/>
  9.             </parser>
  11. 			<group name="HeaderRecord">
  12. 				<record>
  13. 				.
  14. 				.
  15. 				.
  16. 				</record>
  17. 			</group>
  18. 			<group name="GroupHeader">
  19. 			    <record>
  20. 				.
  21. 				.
  22. 				.
  23. 				.
  24. 				</record>
  25. 			</group>
  26. 		</stream>
  27. </beanio>

File that contains records looks like this

  1. 1   File Header|
  2. .   HeaderRecord text.....
  3. .   GroupHeader text......
  4. 19  Response Codes:
  5. 20                 |A - StackOverflow           |                
  6. 21                 |B - Facebook                |               
  7. 22                 |C - Google                  |                
  8. 23  |File Trailer|
  12. Error 
  13. java.lang.IllegalArgumentException: Comments require reader.markSupported() to return true
  14. 	at org.beanio.stream.util.CommentReader.<init>(CommentReader.java:61)
  15. 	at org.beanio.stream.delimited.DelimitedReader.<init>(DelimitedReader.java:149)
  16. 	at org.beanio.stream.delimited.DelimitedRecordParserFactory.createReader(DelimitedRecordParserFactory.java:56)
  17. 	at org.beanio.internal.parser.StreamFormatSupport.createRecordReader(StreamFormatSupport.java:61)
  18. 	at org.beanio.internal.parser.Stream.createBeanReader(Stream.java:88)

I want to ignore File Header, Trailer & Response Codes. Response codes starts in next line. Various blogs suggested for comments in property. Can anyone explain why it is not working?

答案1

得分: 2

问题出在你使用的Reader实现上，用于从中读取数据，正如错误消息所指示的：

> java.lang.IllegalArgumentException: Comments require
> reader.markSupported() to return true

你需要使用支持缓冲的Reader，也就是实现了mark()和reset()方法的Reader。请参考文档的4.1.2节以及关于comments属性名称的描述和解释，其中指出：

> 用于识别注释行的一组以逗号分隔的值。如果从输入流中读取的行以配置的任何值开头，那么该行将被忽略。反斜杠可以用于转义逗号和它本身。所有的空白字符都会被保留。
>
> 要启用注释，需要确保传递给StreamFactory的输入读取器支持标记(mark)。Java的BufferedReader和StringReader等读取器支持标记。

为了使注释正常工作，你需要使用BufferedReader或StringReader来读取数据：

  1. InputStream inputStream = ... // 获取到数据源的某个输入流 
  2. Reader reader = new BufferedReader(new InputStreamReader(inputStream));
  3. BeanReader beanReader = factory.createReader("streamName", reader);
英文:

The problem is with the Reader implementation that you used to read the data from as indicated by the error message:

> java.lang.IllegalArgumentException: Comments require
> reader.markSupported() to return true

You need to use a Reader that supports buffering, i.e. a Reader that implements the mark() and reset() methods. See section 4.1.2 of the documentation and the description and explanation for the comments property name, which states:

> A comma separated list of values for identifying commented lines. If a
> line read from an input stream begins with any of the configured
> values, the line is ignored. A backslash may be used to escape a comma
> and itself. All whitespace is preserved.
>
> Enabling comments require the input reader passed to StreamFactory to
> support marking. Among others, Java's BufferedReader and StringReader
> support marking.

For comments to work you need to read the data with either a BufferedReader or a StringReader

  1. InputStream inputStream = ... // obtain some input stream to the source of your data 
  2. Reader reader = new BufferedReader(new InputStreamReader(inputStream));
  3. BeanReader beanReader = factory.createReader("streamName", reader);

huangapple
  • 本文由 发表于 2020年8月10日 19:08:32
  • 转载请务必保留本文链接：https://go.coder-hub.com/63338987.html
  • bean-io
  • java
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