java - 如何获得所有具有相同模式的字符串

Question

我有一个具有此结构的 xml 文件

<expression>[Customer ].[Sales ].[L_MOIS]</expression><expression>cast_varchar([Customer ].[Sales ].[L_MOIS_ANNEE])
+ ' ' + 
cast_varchar([Customer ].[Sales ].[C_ANNEE])</expression></dataItem></selection><detailFilters><detailFilter><filterExpression>[Customer ].[Sales ].[DT_JOUR] <= getdate()</filterExpression></detailFilter></detailFilters></query><query name="RSmag"><source><model /></source><selection><dataItem aggregate="none" name="Code magasin"><expression>[Customer statistics].[Stores].[C_MAGASIN]</expression></dataItem><dataItem aggregate="none" name="Libellé magasin" sort="ascending"><expression>[Customer statistics].[Stores].[L_MAGASIN]</expression></dataItem></selection><detailFilters><detailFilter><filterExpression>[Customer statistics].[Stores].[C_DEPOT] <>'500'</filterExpression></detailFilter><detailFilter><filterExpression>[Customer statistics].[Stores].[C_MAGASIN] not in ('005120';'005130';'005140')</filterExpression></detailFilter></detailFilters>
</query><query name="CAdept_avec_metier_cumul"><source><model /></source><selection><dataItem aggregate="none" name="Cod Metier" rollupAggregate="none"><expression>[Customer ].[Articles].[COD_DPTG]</expression></dataItem><dataItem name="Nombre de tickets" rollupAggregate="total">
<expression>count(distinct [Customer ].[Sales ].[ID_TICKET])</expression></dataItem><dataItem name="Nombre de tickets non affecté" rollupAggregate="total"><expression>count(distinct 
(case 
when [Customer ].[Sales ].[C_AFFECTATION] <> 1  
then [Customer ].[Sales ].[ID_TICKET]
else null 
end)
)</expression>

我想提取选项卡的所有名称，结果我应该有:[客户].[销售].[C_ANNEE][客户].[销售].[DT_JOUR]

但现在我得到的是:

客户

销售

C_ANNEE

File f = new File("");  
        BufferedReader in = new BufferedReader(
                new InputStreamReader(new FileInputStream(f), "UTF-8"));
        String str;
        while ((str = in.readLine()) != null) {

            Matcher m = Pattern.compile("\\[(.*?)\\]").matcher(str);
            while (m.find()) {
                listres.add(m.group(1));

            }
        }

Answer 1

将问题分成两个独立的部分:

1)使用合适的XML解析器解析XML数据，以提取我们想要的文本。

2)对于提取的文本字段，使用正则表达式提取所需的子字符串。

以下示例使用 SAX 解析器(顺便说一下，我使用的是 Java 13)。

假设我们有一个包含以下 XML 的文件:

<root>
<query name="RSmag">
  <source>
    <model />
  </source>
  <selection>
    <dataItem aggregate="none" name="Code magasin">
      <expression>
        [Customer ].[Sales ].[L_MOIS]
      </expression>
      <expression>
        cast_varchar([Customer ].[Sales ].[L_MOIS_ANNEE]) + ' ' + cast_varchar([Customer ].[Sales ].[C_ANNEE])
      </expression>
    </dataItem>
  </selection>
  <detailFilters>
    <detailFilter>
      <filterExpression>
        [Customer ].[Sales ].[DT_JOUR] &lt;= getdate()
      </filterExpression>
    </detailFilter>
  </detailFilters>
</query>
<query name="RSmag">
  <source>
    <model />
  </source>
  <selection>
    <dataItem aggregate="none" name="Code magasin">
      <expression>
        [Customer statistics].[Stores].[C_MAGASIN]
      </expression>
    </dataItem>
    <dataItem aggregate="none" name="Libellé magasin" sort="ascending">
      <expression>
        [Customer statistics].[Stores].[L_MAGASIN]
      </expression>
    </dataItem>
  </selection>
  <detailFilters>
    <detailFilter>
      <filterExpression>
        [Customer statistics].[Stores].[C_DEPOT] &lt;&gt; '500'
      </filterExpression>
    </detailFilter>
    <detailFilter>
      <filterExpression>
        [Customer statistics].[Stores].[C_MAGASIN] 
        not in ('005120';'005130';'005140')
      </filterExpression>
    </detailFilter>
  </detailFilters>
</query>
<query name="CAdept_avec_metier_cumul">
  <source>
    <model />
  </source>
  <selection>
    <dataItem aggregate="none" name="Cod Metier" rollupAggregate="none">
      <expression>
        [Customer ].[Articles].[COD_DPTG]
      </expression>
    </dataItem>
    <dataItem name="Nombre de tickets" rollupAggregate="total">
      <expression>
        count(distinct [Customer ].[Sales ].[ID_TICKET])
      </expression>
    </dataItem>
    <dataItem name="Nombre de tickets non affecté" rollupAggregate="total">
      <expression>count(distinct 
                  (case 
                   when [Customer ].[Sales ].[C_AFFECTATION] &lt;&gt; 1  
                   then [Customer ].[Sales ].[ID_TICKET]
                   else null 
                   end)
                  )
      </expression>
    </dataItem>
  </selection>
</query>
</root>

注意以下几点:

a) 我根据问题的示例数据做出了创建有效 XML 文档的有根据的猜测。

b) 我逃脱了 <和>文本中的符号，通过使用 <和> .

第 1 步 - 解析数据

此解决方案uses SAX对于解析 - 有很多替代方案。

以下命令将读取输入文件的每一行，并丢弃任何不属于 <expression> 的标签。或<filterExpression>标签。该设置可以根据需要进行调整( watchedElements )。

代码收集每个标签内的文本，并通过删除换行符和额外的空格来清理它。

这为我们提供了一组 10 个文本字符串，如下所示:

[Customer ].[Sales ].[L_MOIS]
cast_varchar([Customer ].[Sales ].[L_MOIS_ANNEE]) + ' ' + cast_varchar([Customer ].[Sales ].[C_ANNEE])
[Customer ].[Sales ].[DT_JOUR] <= getdate()
[Customer statistics].[Stores].[C_MAGASIN]
[Customer statistics].[Stores].[L_MAGASIN]
[Customer statistics].[Stores].[C_DEPOT] <> '500'
[Customer statistics].[Stores].[C_MAGASIN] not in ('005120';'005130';'005140')
[Customer ].[Articles].[COD_DPTG]
count(distinct [Customer ].[Sales ].[ID_TICKET])
count(distinct (case when [Customer ].[Sales ].[C_AFFECTATION] <> 1 then [Customer ].[Sales ].[ID_TICKET] else null end) )

第 2 步 - 应用正则表达式

对于每个字符串，我们使用正则表达式来查找我们想要的数据:

\[.*?\](\.\[.*?\])*

这会搜索开头的“[”，一直到下一个“]”，并重复此操作以查找零个或多个以句点分隔的后续“[”和“]”字符串。

为了处理不需要的子匹配，我们只保留组零:

Matcher m = pattern.matcher(text);
while (m.find()) {
    System.out.println("*** Matches found  : " + m.group(0));
}

这为我们提供了以下 12 个结果:

[Customer ].[Sales ].[L_MOIS]
[Customer ].[Sales ].[L_MOIS_ANNEE]
[Customer ].[Sales ].[C_ANNEE]
[Customer ].[Sales ].[DT_JOUR]
[Customer statistics].[Stores].[C_MAGASIN]
[Customer statistics].[Stores].[L_MAGASIN]
[Customer statistics].[Stores].[C_DEPOT]
[Customer statistics].[Stores].[C_MAGASIN]
[Customer ].[Articles].[COD_DPTG]
[Customer ].[Sales ].[ID_TICKET]
[Customer ].[Sales ].[C_AFFECTATION]
[Customer ].[Sales ].[ID_TICKET]

完整解决方案

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import java.util.Set;
import java.util.HashSet;
import java.util.regex.Pattern;
import java.util.regex.Matcher;

public class ParseFromFileUsingSax {

    // Looks for an opening "[" followed by a closing "]" with an 
    // optional "." to string items together into one group.
    Pattern pattern = Pattern.compile("\\[.*?\\](\\.\\[.*?\\])*");

    public void parseUsingSax() {
        try {

            SAXParserFactory factory = SAXParserFactory.newInstance();
            SAXParser saxParser = factory.newSAXParser();

            // the tags we will inspect (all others will be skipped):
            Set<String> watchedElements = new HashSet();
            watchedElements.add("expression");
            watchedElements.add("filterExpression");

            DefaultHandler handler = new DefaultHandler() {

                private boolean inElement = false;
                private StringBuilder stringBuilder;

                @Override
                public void startElement(String uri, String localName, String name,
                        Attributes attributes) throws SAXException {
                    if (watchedElements.contains(name)) {
                        inElement = true;
                        stringBuilder = new StringBuilder();
                    }
                }

                @Override
                public void characters(char[] buffer, int start, int length) throws SAXException {
                    if (inElement) {
                        stringBuilder.append(buffer, start, length);
                    }
                }

                @Override
                public void endElement(String uri, String localName,
                        String name) throws SAXException {
                    if (watchedElements.contains(name)) {
                        inElement = false;
                        String extractedText = formatString(stringBuilder.toString());
                        System.out.println();
                        System.out.println("Extracted XML text : " + extractedText);
                        printMatches(extractedText);
                    }
                }

            };

            saxParser.parse("C:/tmp/query_data.xml", handler);

        } catch (Exception e) {
            System.err.print(e);
        }

    }

    private String formatString(String text) {
        text = text.replaceAll("\\r\\n|\\r|\\n", " "); // remove newlines
        text = text.replaceAll("  *", " "); // collapse multiple spaces
        return text.trim(); // remove leading/trailing whitespace
    }

    private void printMatches(String text) {
        Matcher m = pattern.matcher(text);
        while (m.find()) {
            System.out.println("*** Matches found  : " + m.group(0));
        }
    }

}