如何使用JAXB读取XML文件？ [英] How to read an XML file with JAXB?

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问题描述

我使用JAXB从XML模式生成Java类。现在我想用这些类读取XML文件，但不能。我试试这个

I use JAXB to generate Java classes from XML schema. Now I want to read an XML file with these classes, but can't. I try this 

    JAXBContext jaxbContext = JAXBContext.newInstance(STDMP.class);
    Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
    STDMP ts = (STDMP)jaxbUnmarshaller.unmarshal(xml_gkuzu);
    System.out.println(ts.getEDocument().getSender().getName());

并获得此异常

Exception in thread "main" java.lang.NullPointerException
at java.util.EnumMap.<init>(EnumMap.java:113)
at com.sun.xml.bind.v2.model.impl.RuntimeEnumLeafInfoImpl.<init>(RuntimeEnumLeafInfoImpl.java:87)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.createEnumLeafInfo(RuntimeModelBuilder.java:109)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.createEnumLeafInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:229)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:104)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:214)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:99)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:320)
at com.sun.xml.bind.v2.model.impl.SingleTypePropertyInfoImpl.getTarget(SingleTypePropertyInfoImpl.java:94)
at com.sun.xml.bind.v2.model.impl.RuntimeAttributePropertyInfoImpl.getTarget(RuntimeAttributePropertyInfoImpl.java:66)
at com.sun.xml.bind.v2.model.impl.RuntimeAttributePropertyInfoImpl.getTarget(RuntimeAttributePropertyInfoImpl.java:54)
at com.sun.xml.bind.v2.model.impl.SingleTypePropertyInfoImpl.ref(SingleTypePropertyInfoImpl.java:88)
at com.sun.xml.bind.v2.model.impl.RuntimeAttributePropertyInfoImpl.ref(RuntimeAttributePropertyInfoImpl.java:70)
at com.sun.xml.bind.v2.model.impl.RuntimeAttributePropertyInfoImpl.ref(RuntimeAttributePropertyInfoImpl.java:54)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:260)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:104)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:214)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:99)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:320)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.calcRef(TypeRefImpl.java:96)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.getTarget(TypeRefImpl.java:73)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:62)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:55)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:78)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:76)
at java.util.AbstractList$Itr.next(AbstractList.java:345)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:260)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:104)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:214)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:99)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:320)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.calcRef(TypeRefImpl.java:96)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.getTarget(TypeRefImpl.java:73)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:62)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:55)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:78)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:76)
at java.util.AbstractList$Itr.next(AbstractList.java:345)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:260)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:104)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:214)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:99)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:320)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.calcRef(TypeRefImpl.java:96)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.getTarget(TypeRefImpl.java:73)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:62)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:55)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:78)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:76)
at java.util.AbstractList$Itr.next(AbstractList.java:345)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:260)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:104)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:214)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:99)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:320)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.calcRef(TypeRefImpl.java:96)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.getTarget(TypeRefImpl.java:73)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:62)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:55)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:78)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:76)
at java.util.AbstractList$Itr.next(AbstractList.java:345)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:260)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:104)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:214)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:99)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:320)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.calcRef(TypeRefImpl.java:96)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.getTarget(TypeRefImpl.java:73)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:62)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:55)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:78)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:76)
at java.util.AbstractList$Itr.next(AbstractList.java:345)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:260)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:104)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:214)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:99)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:320)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.calcRef(TypeRefImpl.java:96)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.getTarget(TypeRefImpl.java:73)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:62)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:55)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:78)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:76)
at java.util.AbstractList$Itr.next(AbstractList.java:345)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:260)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:104)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:214)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:99)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:320)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.calcRef(TypeRefImpl.java:96)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.getTarget(TypeRefImpl.java:73)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:62)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:55)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:78)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:76)
at java.util.AbstractList$Itr.next(AbstractList.java:345)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:260)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:104)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:214)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:99)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:320)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.calcRef(TypeRefImpl.java:96)
at com.sun.xml.bind.v2.model.impl.TypeRefImpl.getTarget(TypeRefImpl.java:73)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:62)
at com.sun.xml.bind.v2.model.impl.RuntimeTypeRefImpl.getTarget(RuntimeTypeRefImpl.java:55)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:78)
at com.sun.xml.bind.v2.model.impl.ElementPropertyInfoImpl$1.get(ElementPropertyInfoImpl.java:76)
at java.util.AbstractList$Itr.next(AbstractList.java:345)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:260)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:104)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getClassInfo(ModelBuilder.java:214)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:99)
at com.sun.xml.bind.v2.model.impl.RuntimeModelBuilder.getClassInfo(RuntimeModelBuilder.java:85)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:320)
at com.sun.xml.bind.v2.model.impl.ModelBuilder.getTypeInfo(ModelBuilder.java:335)
at com.sun.xml.bind.v2.runtime.JAXBContextImpl.getTypeInfoSet(JAXBContextImpl.java:465)
at com.sun.xml.bind.v2.runtime.JAXBContextImpl.<init>(JAXBContextImpl.java:303)
at com.sun.xml.bind.v2.runtime.JAXBContextImpl.<init>(JAXBContextImpl.java:142)
at com.sun.xml.bind.v2.runtime.JAXBContextImpl$JAXBContextBuilder.build(JAXBContextImpl.java:1174)
at com.sun.xml.bind.v2.ContextFactory.createContext(ContextFactory.java:162)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javax.xml.bind.ContextFinder.newInstance(ContextFinder.java:202)
at javax.xml.bind.ContextFinder.find(ContextFinder.java:363)
at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:574)
at javax.xml.bind.JAXBContext.newInstance(JAXBContext.java:522)
at net.sf.hibernate.examples.quickstart.hib_main.main(hib_main.java:83)

我不明白什么是错的。

我试图通过Dangling Piyush生成的代码和类来获取CoordSystem Name。

I tried to get CoordSystem Name with code and classes generated by Dangling Piyush.

代码

        File xml_gkuzu = new File("D:/liferay-develop/workspace/cat_test/XML/GKUZU_53ce0a8e-13e1-4e4e-99d9-2f45ae786d33!chz.xml");
    JAXBContext jaxbContext = JAXBContext.newInstance(CoordSystem.class);
SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
Schema schema = factory.newSchema(new StreamSource(new File("D:/liferay-develop/workspace/cat_test/v2/STD_MP.xsd")));
Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
jaxbUnmarshaller.setSchema(schema);
CoordSystem cs = (CoordSystem)jaxbUnmarshaller.unmarshal(xml_gkuzu);
System.out.println(cs.getName());

但在行中获取异常CoordSystem cs =（CoordSystem）jaxbUnmarshaller.unmarshal （xml_gkuzu）; 

Exception in thread "main" javax.xml.bind.UnmarshalException: unexpected element (uri:"", local:"STD_MP"). Expected elements are <{}Coord_System>


推荐答案

我想建议

 jaxbUnmarshaller.setSchema(schemaLocation);

通过执行此操作，您可以检查xml是否针对xsd进行验证，您还可以查看通过读取SAXException或JAXBException的堆栈跟踪来解决xml中的问题。

By doing this you can check whether your xml is validating against xsd or not and you can also find out where is the problem in xml by reading the stacktrace of SAXException or JAXBException.

更新：

这是生成的java类的链接

This is the link for generated java classses

生成的Java类

以下是xml的解组代码，对xsd进行了验证。

And follwing is the unmarshalling code for xml with validation against xsd.

import java.io.File;
import javax.xml.XMLConstants;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;

import org.xml.sax.SAXException;

import com.piyush.STDMP;


public class Test {

    /**
     * @param args
     * @throws JAXBException 
     * @throws SAXException 
     */
    public static void main(String[] args) throws JAXBException, SAXException {
        JAXBContext jaxbContext = JAXBContext.newInstance(STDMP.class);
        SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
        Schema schema = factory.newSchema(new StreamSource(new File("C:/Users/CDAC/workspace/Testing/src/STD_MP.xsd")));
        Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
        jaxbUnmarshaller.setSchema(schema);
        STDMP ts = (STDMP)jaxbUnmarshaller.unmarshal(new File("E:/Testing.xml"));

        System.out.println(ts.getCoordSystems());
        System.out.println(ts.getEDocument());

    }

     }

请更改根据您的机器的xsd和xml位置。

Please change the xsd and xml location according to your machine.

这篇关于如何使用JAXB读取XML文件？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

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