java - 如何仅将具有 xml 标签的文本文件中的某些元素打印到新文本文件中？

Question

我需要帮助来解决一些听起来很简单但给我带来了一些麻烦的事情。

我有一个文本文件 (record.txt)，其中包含根元素“PatientRecord”和一遍又一遍重复的子标签(“名字”、“年龄”、血型、地址等...)但具有不同的值，因为它是每个人的记录。我只感兴趣将标签之间的值打印到每个人的新文本文件中，但仅限于我想要的元素。例如，对于我上面提到的标签，我只需要姓名和年龄，而不需要该患者的其余信息。如何只打印那些用逗号分隔的值，然后转到下一个患者？这是我到目前为止的代码

    package patient.records;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.OutputStreamWriter;
import java.io.Writer;
public class ProcessRecords {
private static final String FILE = "C:\\Users\\Desktop\\records.txt";
private static final String RECORD_START_TAG = "<PatientRecord>";
private static final String RECORD_END_TAG = "</PatientRecord>"; 
private static final String newFileName = "C:\\Users\\Desktop\\DataFolder\\";    
public static void main(String[] args) throws Exception {
    String scan;    
    FileReader file = new FileReader(FILE);
    BufferedReader br = new BufferedReader(file);
    Writer writer = null;

    while ((scan = br.readLine()) != null)        
    {            
        if (scan.contains(RECORD_START_TAG)) { 


            //This is the logic I am missing that will only grab the element values
            //between the tags inside of the file

            writer = new BufferedWriter(new OutputStreamWriter(
            new FileOutputStream(newFileName + "Record Data" + ".txt"), "utf-8"));             
            }      
        else if (scan.contains(RECORD_END_TAG)) {
            writer.close();
            writer=null;
        }
        else {
            // only write if writer is not null
           if (writer!=null) {
            writer.write(scan);
           }
        }            
    }       
    br.close();
    }   
}   //This is the end of my code             

<小时/>

我正在读取的文本文件(record.txt)如下所示:

<PatientRecord> <---first patient record--->
<---XML Schema goes here--->
            <Info>
                <age>66</age>
                <first_name>john</first_name>
                <last_name>smith</last_name>
                <mailing_address>200 main street</mailing_address>
                <blood_type>AB</blood_type>
                <phone_number>000-000-0000</phone_number>
</PatientRecord>
<PatientRecord> <---second patient record--->
<---XML Schema goes here--->
            <Info>
                <age>27</age>
                <first_name>micheal</first_name>
                <last_name>thompson</last_name>
                <mailing_address>123 baker street</mailing_address>
                <blood_type>O</blood_type>
                <phone_number>111-222-3333</phone_number>
</PatientRecord>

因此，理论上，如果我只想打印此文本文件中所有患者的名字、邮寄地址和血型标签的值，它应该如下所示:

john, 200 main street, AB
//this line is blank
michael, 123 baker street, O

感谢您的所有帮助。如果您觉得我的代码应该修改，那么我完全赞成。谢谢。

Answer 1

我的第一个直觉是将整个文本内容包裹在某个外部标记周围，并将文本处理为 XML，类似于...

<Patients>
    <PatientRecord> <---first patient record--->
        <Info>
            <age>66</age>
            <first_name>john</first_name>
            <last_name>smith</last_name>
            <mailing_address>200 main street</mailing_address>
            <blood_type>AB</blood_type>
            <phone_number>000-000-0000</phone_number>
    </PatientRecord>
    ...
</Patients>

但是这有两个问题......

一个<---first patient record--->不是有效的 XML 注释或文本，两个，没有结束 </Info>标签...[叹气]

所以，我的下一个想法是，阅读每个<PatientRecord>个人，作为文本，然后将其处理为 XML ....

问题来了...我们需要删除 <--- ... ---> 包围的任何内容包括小箭头...对此有很多假设，但希望我们可以忽略它...

下一个问题是，我们需要插入结束语 </Info>标签...

之后，一切都变得非常简单......

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.SAXException;

public class Test {

    private static final String RECORD_START_TAG = "<PatientRecord>";
    private static final String RECORD_END_TAG = "</PatientRecord>";

    public static void main(String[] args) {
        File records = new File("Records.txt");
        try (BufferedReader br = new BufferedReader(new FileReader(records))) {
            StringBuilder record = null;
            String text = null;
            while ((text = br.readLine()) != null) {

                if (text.contains("<---") && text.contains("--->")) {
                    String start = text.substring(0, text.indexOf("<---"));
                    String end = text.substring(text.indexOf("--->") + 4);
                    text = start + end;
                }

                if (text.trim().length() > 0) {
                    if (text.startsWith(RECORD_START_TAG)) {

                        record = new StringBuilder(128);
                        record.append(text);

                    } else if (text.startsWith(RECORD_END_TAG)) {

                        record.append("</Info>");
                        record.append(text);

                        try (ByteArrayInputStream bais = new ByteArrayInputStream(record.toString().getBytes())) {

                            Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(bais);
                            XPath xPath = XPathFactory.newInstance().newXPath();
                            XPathExpression exp = xPath.compile("PatientRecord/Info/first_name");
                            Node firstName = (Node) exp.evaluate(doc, XPathConstants.NODE);

                            exp = xPath.compile("PatientRecord/Info/mailing_address");
                            Node address = (Node) exp.evaluate(doc, XPathConstants.NODE);

                            exp = xPath.compile("PatientRecord/Info/blood_type");
                            Node bloodType = (Node) exp.evaluate(doc, XPathConstants.NODE);

                            System.out.println(
                                    firstName.getTextContent() + ", "
                                    + address.getTextContent() + ", "
                                    + bloodType.getTextContent());

                        } catch (ParserConfigurationException | XPathExpressionException | SAXException ex) {
                            ex.printStackTrace();
                        }

                    } else {

                        record.append(text);

                    }

                }

            }
        } catch (IOException exp) {
            exp.printStackTrace();
        }
    }

}

打印出...

john, 200 main street, AB
micheal, 123 baker street, O

总而言之，回到给你这个文件的人，打他们一巴掌，然后告诉他们将其转换为有效的 XML 格式...