java - CSV 到 XML 转换 Java

Question

我正在致力于将 CSV 数据转换为 XML 数据。通过查看各种示例，我能够编写用于解析 CSV 文件并获取 XML 文件的代码。但是，我编写的代码返回带有错误标签的 XML 文件。

这是转换代码:

    package com.adarsh.parse;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.StringTokenizer;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.FactoryConfigurationError;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;



public class Converter {

    /* Protected members to avoid instantiation */
    protected DocumentBuilderFactory domFactory = null;
    protected DocumentBuilder domBuilder = null;
    /* Constant strings */
    // Input CSV file
    final String INPUT_FILE = "sample_data.csv";
    // Output XML document
    final String OUTPUT_FILE ="in.xml";
    // First element in the XML document
    final String FIRST_ELEMENT="school";
    public Converter(){
        try {
            domFactory = DocumentBuilderFactory.newInstance();
            /* Obtaining instance of class DocumentBuilder */
            domBuilder = domFactory.newDocumentBuilder();
        }
        catch(ParserConfigurationException exp) {
            System.err.println(exp.toString());

        }
        catch(FactoryConfigurationError exp){
            System.err.println(exp.toString());
        }
        catch(Exception exp){
            System.err.println(exp.toString());
        }
    }
    /**
     * This method converts the given CSV file into an XML document
     */
    public  int convert(String csvFileName, String xmlFileName) {
        int rowCount = -1;
        try {
            /* Initializing the XML document  */
            Document newDoc = domBuilder.newDocument();
            /* Creating the root element in the XML */
            Element rootElem = newDoc.createElement(FIRST_ELEMENT);
            newDoc.appendChild(rootElem);
            /* Reading the CSV file */
            BufferedReader csvFileReader;
            csvFileName = INPUT_FILE;
            csvFileReader = new BufferedReader(new FileReader(csvFileName));
            /* Initialize the number of fields to 0 */
            int fieldCount = 0;
            String[] csvFields = null;
            StringTokenizer stringTokenizer = null;

            /**
             * Map the column names in the CSV file as the elements in the XML
             * document, eliminate any other characters not eligible for XML element
             * naming
             */
            /* Initialize the current line variable */
            String currLine = csvFileReader.readLine();
            /* Loop until we reach the end of the file 
             * edge case: Empty CSV file
             * */

            if(currLine != null) {
                /* Separate fields based on commas */
                stringTokenizer = new StringTokenizer(currLine, ",");
                fieldCount = stringTokenizer.countTokens();
                /* If there is data in the CSV file */
                if(fieldCount > 0) {
                    /* Initialize a String Array of Fields */
                    csvFields = new String[fieldCount];
                    int i = 0;
                    /* Loop till all elements are found and save fields */
                    while (stringTokenizer.hasMoreElements()) {
                        csvFields[i++] = String.valueOf(stringTokenizer.nextElement());
                    }
                }

            }
            else {
                System.out.println("Nothing to parse");
            }
            /* reading rows from the CSV file */
            while((currLine = csvFileReader.readLine()) != null) {
                stringTokenizer = new StringTokenizer(currLine, ",");
                fieldCount = stringTokenizer.countTokens();
                /* if rows exist in the CSV file*/
                if(fieldCount > 0) {
                    /* Create the row element*/
                    Element rowElem = newDoc.createElement("row");
                    int i = 0;
                    /* until there are more elements*/
                    while(stringTokenizer.hasMoreElements()) {
                        try {
                            /* Append each element found to each row element*/
                            String currValue = String.valueOf(stringTokenizer.nextElement());
                            Element currElem = newDoc.createElement(csvFields[i++]);
                            currElem.appendChild(newDoc.createTextNode(currValue));
                            rowElem.appendChild(currElem);
                        }
                        catch(Exception exp) {

                        }
                    }
                    /* Append the rows to the root element*/
                    rootElem.appendChild(rowElem);
                    rowCount++;
                }
            }
            /* Finish reading the CSV file */
            csvFileReader.close();

            /* Saving the generated XML doc into required format file to disk */
            TransformerFactory tranFactory = TransformerFactory.newInstance(); 
            Transformer aTransformer = tranFactory.newTransformer(); 
            aTransformer.setOutputProperty(OutputKeys.INDENT, "yes");
            aTransformer.setOutputProperty(OutputKeys.METHOD, "xml");
            aTransformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
            Source src = new DOMSource(newDoc);
            xmlFileName = OUTPUT_FILE;
            Result dest = new StreamResult(new File(xmlFileName)); 
            aTransformer.transform(src, dest); 

            rowCount++;
        }
        catch(IOException exp) {
            System.err.println(exp.toString());
        }
        catch(Exception exp) {
            System.err.println(exp.toString());
        }
        /* Number of rows parsed into XML */
        return rowCount;

    }

}

这是文件中的示例 CSV 数据:

classroom_id,classroom_name,teacher_1_id,teacher_1_last_name,teacher_1_first_name,teacher_2_id,teacher_2_last_name,teacher_2_first_name,student_id,student_last_name,student_first_name,student_grade 103, Brian's Homeroom, 10300000001, O'Donnell, Brian, , , , , , , 102, Mr. Smith's PhysEd Class, 10200000001, Smith, Arthur, 10200000011, Patterson, John, 10200000011, McCrancy, Brandon, 1 102, Mr. Smith's PhysEd Class, 10200000001, Smith, Arthur, 10200000011, Patterson, John, 10200000018, Reginald, Alexis, 1 102, Mr. Smith's PhysEd Class, 10200000001, Smith, Arthur, 10200000011, Patterson, John, 10200000019, Gayle, Matthew, 1 102, Mr. Smith's PhysEd Class, 10200000001, Smith, Arthur, 10200000011, Patterson, John, 10200000010, Smith, Nathaniel, 1 102, Mr. Smith's PhysEd Class, 10200000001, Smith, Arthur, 10200000011, Patterson, John, 10200000013, Lanni, Erica, 1 102, Mr. Smith's PhysEd Class, 10200000001, Smith, Arthur, 10200000011, Patterson, John, 10200000014, Flores, Michael, 1 102, Mr. Smith's PhysEd Class, 10200000001, Smith, Arthur, 10200000011, Patterson, John, 10200000012, Marco, Elizabeth, 1 102, Mr. Smith's PhysEd Class, 10200000001, Smith, Arthur, 10200000011, Patterson, John, 10200000016, Perez, Brittany, 1 102, Mr. Smith's PhysEd Class, 10200000001, Smith, Arthur, 10200000011, Patterson, John, 10200000015, Hill, Jasmin, 1 102, Mr. Smith's PhysEd Class, 10200000001, Smith, Arthur, 10200000011, Patterson, John, 10200000017, Hiram, William, 1 101, Mrs. Jones' Math Class, 10100000001, Jones, Barbara, , , , 10100000015, Cruz, Alex, 1 101, Mrs. Jones' Math Class, 10100000001, Jones, Barbara, , , , 10100000014, Garcia, Lizzie, 1 101, Mrs. Jones' Math Class, 10100000001, Jones, Barbara, , , , 10100000013, Mercado, Toby, 1 101, Mrs. Jones' Math Class, 10100000001, Jones, Barbara, , , , 10100000011, Gutierrez, Kimberly, 2 101, Mrs. Jones' Math Class, 10100000001, Jones, Barbara, , , , 10100000010, Gil, Michael, 2

我期望在 XML 文件中获得如下输出:

<grade id="1">
    <classroom id="101" name="Mrs. Jones' Math Class">
        <teacher id="10100000001" first_name="Barbara" last_name="Jones"/>

        <student id="10100000010" first_name="Michael" last_name="Gil"/>
        <student id="10100000011" first_name="Kimberly" last_name="Gutierrez"/>
        <student id="10100000013" first_name="Toby" last_name="Mercado"/>
        <student id="10100000014" first_name="Lizzie" last_name="Garcia"/>
        <student id="10100000015" first_name="Alex" last_name="Cruz"/>
    </classroom>


    <classroom id="102" name="Mr. Smith's PhysEd Class">
        <teacher id="10200000001" first_name="Arthur" last_name="Smith"/>
        <teacher id="10200000011" first_name="John" last_name="Patterson"/>

        <student id="10200000010" first_name="Nathaniel" last_name="Smith"/>
        <student id="10200000011" first_name="Brandon" last_name="McCrancy"/>
        <student id="10200000012" first_name="Elizabeth" last_name="Marco"/>
        <student id="10200000013" first_name="Erica" last_name="Lanni"/>
        <student id="10200000014" first_name="Michael" last_name="Flores"/>
        <student id="10200000015" first_name="Jasmin" last_name="Hill"/>
        <student id="10200000016" first_name="Brittany" last_name="Perez"/>
        <student id="10200000017" first_name="William" last_name="Hiram"/>
        <student id="10200000018" first_name="Alexis" last_name="Reginald"/>
        <student id="10200000019" first_name="Matthew" last_name="Gayle"/>
    </classroom>

    <classroom id="103" name="Brian's Homeroom">
        <teacher id="10300000001" first_name="Brian" last_name="O'Donnell"/>
    </classroom>
</grade>

这就是我当前获取输出的方式:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<school>
    <row>
        <classroom_id>101</classroom_id>
    </row>
    <row>
        <classroom_id>101</classroom_id>
    </row>
    <row>
        <classroom_id>101</classroom_id>
    </row>
    <row>
        <classroom_id>101</classroom_id>
    </row>
    <row>
        <classroom_id>101</classroom_id>
    </row>
    <row>
        <classroom_id>102</classroom_id>
    </row>
    <row>
        <classroom_id>102</classroom_id>
    </row>
    <row>
        <classroom_id>102</classroom_id>
    </row>
    <row>
        <classroom_id>102</classroom_id>
    </row>
    <row>
        <classroom_id>102</classroom_id>
    </row>
    <row>
        <classroom_id>102</classroom_id>
    </row>
    <row>
        <classroom_id>102</classroom_id>
    </row>
    <row>
        <classroom_id>102</classroom_id>
    </row>
    <row>
        <classroom_id>102</classroom_id>
    </row>
    <row>
        <classroom_id>102</classroom_id>
    </row>
    <row>
        <classroom_id>103</classroom_id>
    </row>
</school>

有人可以帮我解决这个问题吗？我想知道我哪里出了问题。谢谢

附注我已经在 stackoverflow 上提到了有关 CSV 到 XML 转换的其他问题。但是，我无法找到适合我的问题的合适解决方案或解释。

附注如果不需要将此类 CSV 数据解析为 XML，请不要建议我使用 XSLT。如果没有其他选择，那么我就必须去学习 XSLT，因为我对 XSLT 的了解很少。如果您建议对我已经编写的代码进行更改，我将不胜感激。

Answer 1

您的 CSV 内容似乎没有换行符。