Question

我试图从XML文件读取一些数据并遇到一些麻烦，我的XML如下：

<xml version="1.0" encoding="UTF-8"?>

<EmailSettings>
    <recipient>test@test.com</recipient>
    <sender>test2@test.com</sender>
    <subject>Sales Query</subject>
    <description>email body message</description>
</EmailSettings>

我试图将这些值作为字符串读入我的Java程序，到目前为止我编写了这段代码：

private static Document getDocument (String filename){
    try {

        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

        factory.setIgnoringComments(true);
        factory.setIgnoringElementContentWhitespace(true);
        factory.setValidating(false);

        DocumentBuilder builder = factory.newDocumentBuilder();
        return builder.parse(new InputSource(filename));        
    }
    catch (Exception e){
        System.out.println("Error reading configuration file:");
        System.out.println(e.getMessage());
    }
    return null;
}

Document doc = getDocument(configFileName);

Element config = doc.getDocumentElement();

我正在努力阅读实际的字符串值。

Answer 1

其中一种可能的实施方式：

File file = new File("userdata.xml");
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory
        .newInstance();
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
Document document = documentBuilder.parse(file);
String usr = document.getElementsByTagName("user").item(0).getTextContent();
String pwd = document.getElementsByTagName("password").item(0).getTextContent();

与XML内容一起使用时：

<credentials>
    <user>testusr</user>
    <password>testpwd</password>
</credentials>

导致"testusr"和"testpwd"被分配到上面的usr和pwd引用。

Answer 2

检查一下 - http://www.developerfusion.com/code/2064/a-simple-way-to-read-an-xml-file-in-java/ - out，你会好的。

或者，另一个类似的一步一步 - http://www.java-samples.com/showtutorial.php?tutorialid=152

Answer 3

以简单的方式阅读xml：

http://www.mkyong.com/java/jaxb-hello-world-example/

package com.mkyong.core;

import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement
public class Customer {

    String name;
    int age;
    int id;

    public String getName() {
        return name;
    }

    @XmlElement
    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    @XmlElement
    public void setAge(int age) {
        this.age = age;
    }

    public int getId() {
        return id;
    }

    @XmlAttribute
    public void setId(int id) {
        this.id = id;
    }

}

package com.mkyong.core;

import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;

public class JAXBExample {
    public static void main(String[] args) {

      Customer customer = new Customer();
      customer.setId(100);
      customer.setName("mkyong");
      customer.setAge(29);

      try {

        File file = new File("C:\\file.xml");
        JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);
        Marshaller jaxbMarshaller = jaxbContext.createMarshaller();

        // output pretty printed
        jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

        jaxbMarshaller.marshal(customer, file);
        jaxbMarshaller.marshal(customer, System.out);

          } catch (JAXBException e) {
              e.printStackTrace();
          }

    }
}

Answer 4

有一篇关于在java中使用xml文件的好博客，请看一下如果您需要更多帮助，请询问任何问题： http://javabrainhelper.blogspot.com/2012/08/read-xml-files.html

Answer 5

避免硬编码尝试使下面动态的代码是它将用于任何xml的代码我使用SAX Parser你可以使用dom，xpath它取决于你我将所有标签名称和值存储在地图中之后，很容易检索到您想要的任何值，我希望这有助于 示例XML：

<parent>
<child >
    <child1> value 1 </child1>
    <child2> value 2 </child2>
    <child3> value 3 </child3>
    </child>
    <child >
     <child4> value 4 </child4>
    <child5> value 5</child5>
    <child6> value 6 </child6>
    </child>
  </parent>

JAVA代码：

 import java.io.File;
    import java.io.IOException;
    import java.util.HashMap;
    import java.util.LinkedHashMap;
    import java.util.Map;
    import javax.xml.parsers.ParserConfigurationException;
    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;


    public class saxParser {
           static Map<String,String> tmpAtrb=null;
           static Map<String,String> xmlVal= new LinkedHashMap<String, String>();
        public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException, VerifyError {

            /**
             * We can pass the class name of the XML parser
             * to the SAXParserFactory.newInstance().
             */

            //SAXParserFactory saxDoc = SAXParserFactory.newInstance("com.sun.org.apache.xerces.internal.jaxp.SAXParserFactoryImpl", null);

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

            DefaultHandler handler = new DefaultHandler() {
                String tmpElementName = null;
                String tmpElementValue = null;


                @Override
                public void startElement(String uri, String localName, String qName, 
                                                                    Attributes attributes) throws SAXException {
                    tmpElementValue = "";
                    tmpElementName = qName;
                    tmpAtrb=new HashMap();
                    //System.out.println("Start Element :" + qName);
                    /**
                     * Store attributes in HashMap
                     */
                    for (int i=0; i<attributes.getLength(); i++) {
                        String aname = attributes.getLocalName(i);
                        String value = attributes.getValue(i);
                        tmpAtrb.put(aname, value);
                    }

                }

                @Override
                public void endElement(String uri, String localName, String qName) 
                                                            throws SAXException { 

                    if(tmpElementName.equals(qName)){
                        System.out.println("Element Name :"+tmpElementName);
                    /**
                     * Retrive attributes from HashMap
                     */                    for (Map.Entry<String, String> entrySet : tmpAtrb.entrySet()) {
                            System.out.println("Attribute Name :"+ entrySet.getKey() + "Attribute Value :"+ entrySet.getValue());
                        }
                        System.out.println("Element Value :"+tmpElementValue);
                        xmlVal.put(tmpElementName, tmpElementValue);
                        System.out.println(xmlVal);
                      //Fetching The Values From The Map
                        String getKeyValues=xmlVal.get(tmpElementName);
                        System.out.println("XmlTag:"+tmpElementName+":::::"+"ValueFetchedFromTheMap:"+getKeyValues);   
                    }   
                }
                @Override
                public void characters(char ch[], int start, int length) throws SAXException {
                    tmpElementValue = new String(ch, start, length) ;  
                } 
            };
            /**
             * Below two line used if we use SAX 2.0
             * Then last line not needed.
             */

            //saxParser.setContentHandler(handler);
            //saxParser.parse(new InputSource("c:/file.xml"));
            saxParser.parse(new File("D:/Test _ XML/file.xml"), handler);
        }  
    }

<强>输出：

Element Name :child1
Element Value : value 1 
XmlTag:<child1>:::::ValueFetchedFromTheMap: value 1 
Element Name :child2
Element Value : value 2 
XmlTag:<child2>:::::ValueFetchedFromTheMap: value 2 
Element Name :child3
Element Value : value 3 
XmlTag:<child3>:::::ValueFetchedFromTheMap: value 3 
Element Name :child4
Element Value : value 4 
XmlTag:<child4>:::::ValueFetchedFromTheMap: value 4 
Element Name :child5
Element Value : value 5
XmlTag:<child5>:::::ValueFetchedFromTheMap: value 5
Element Name :child6
Element Value : value 6 
XmlTag:<child6>:::::ValueFetchedFromTheMap: value 6 
Values Inside The Map:{child1= value 1 , child2= value 2 , child3= value 3 , child4= value 4 , child5= value 5, child6= value 6 }

Answer 6

如果选择使用其他库，则以下内容可能更容易：

package for_so;

import java.io.File;

import rasmus_torkel.xml_basic.read.TagNode;
import rasmus_torkel.xml_basic.read.XmlReadOptions;
import rasmus_torkel.xml_basic.read.impl.XmlReader;

public class Q7704827_SimpleRead
{
    public static void
    main(String[] args)
    {
        String fileName = args[0];

        TagNode emailNode = XmlReader.xmlFileToRoot(new File(fileName), "EmailSettings", XmlReadOptions.DEFAULT);
        String recipient = emailNode.nextTextFieldE("recipient");
        String sender = emailNode.nextTextFieldE("sender");
        String subject = emailNode.nextTextFieldE("subject");
        String description = emailNode.nextTextFieldE("description");
        emailNode.verifyNoMoreChildren();

        System.out.println("recipient =  " + recipient);
        System.out.println("sender =     " + sender);
        System.out.println("subject =    " + subject);
        System.out.println("desciption = " + description);
    }
}

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Java - 读取XML文件

6 个答案: