JAXB 模式驗證 · HowToDoInJava 中文系列教程

# JAXB 模式驗證 > 原文： [https://howtodoinjava.com/jaxb/xsd-schema-validation/](https://howtodoinjava.com/jaxb/xsd-schema-validation/) 了解**根據架構（xsd）**驗證 XML，然后將 XML 解組到 Java 對象。如果驗證失敗，還請學習**在 xml 模式驗證**期間檢查驗證錯誤。 > 閱讀更多：[如何從 JAXB 類生成模式](https://howtodoinjava.com/jaxb/java-class-to-xsd-eclipse/) ## 1.在 XSD 驗證后將 XML 轉換為 Java 對象我們已經看到了[將 XML 文件讀取到 Java 對象](https://howtodoinjava.com/jaxb/read-xml-to-java-object/)的示例。現在讓我們修改該示例，以在填充`Employee`對象之前針對 XSD 驗證 XML。 ```java package com.howtodoinjava.demo; 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.validation.Schema; import javax.xml.validation.SchemaFactory; import org.xml.sax.SAXException; import com.howtodoinjava.demo.model.Employee; public class JaxbExample { public static void main(String[] args) { String xmlFile = "employee.xml"; String xsdFile = "employee.xsd"; jaxbXmlFileToObject(xmlFile, xsdFile); } private static void jaxbXmlFileToObject(String xmlFile, String xsdFile) { JAXBContext jaxbContext; try { //Get JAXBContext jaxbContext = JAXBContext.newInstance(Employee.class); //Create Unmarshaller Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller(); //Setup schema validator SchemaFactory sf = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI); Schema employeeSchema = sf.newSchema(new File(xsdFile)); jaxbUnmarshaller.setSchema(employeeSchema); //Unmarshal xml file Employee employee = (Employee) jaxbUnmarshaller.unmarshal(new File(xmlFile)); System.out.println(employee); } catch (JAXBException | SAXException e) { e.printStackTrace(); } } } ``` 程序輸出。 ```java Employee [id=1, firstName=Lokesh, lastName=Gupta, department=Department [id=101, name=IT]] ``` 下面給出`employee.xml`和`employee.xsd`的含量。 ```java <employees> <employee id="101"> <name>Lokesh Gupta</name> <title>Author</title> </employee> <employee id="102"> <name>Brian Lara</name> <title>Cricketer</title> </employee> </employees> ``` ```java <?xml version="1.0" encoding="UTF-8" standalone="yes"?> <xs:schema version="1.0" xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:element name="department" type="department"/> <xs:element name="employee" type="employee"/> <xs:complexType name="employee"> <xs:sequence> <xs:element ref="department" minOccurs="0"/> <xs:element name="firstName" type="xs:string" minOccurs="0"/> <xs:element name="id" type="xs:int" minOccurs="0"/> <xs:element name="lastName" type="xs:string" minOccurs="0"/> </xs:sequence> </xs:complexType> <xs:complexType name="department"> <xs:sequence> <xs:element name="id" type="xs:int" minOccurs="0"/> <xs:element name="name" type="xs:string" minOccurs="0"/> </xs:sequence> </xs:complexType> </xs:schema> ``` ## 2.模式驗證錯誤針對 XML 的 XSD 驗證不會總是成功。很多時候，您會收到驗證錯誤。這些錯誤將作為[`SAXException`](https://docs.oracle.com/javase/10/docs/api/org/xml/sax/SAXException.html)拋出。因此捕獲此異常，它將具有驗證失敗的上下文。例如，我已通過此更改更新了架構文件。 ```java <xs:element name="firstName" type="xs:string" minOccurs="0"/> //to <xs:element name="firstName" type="xs:int" minOccurs="0"/> ``` 現在來看驗證錯誤。 ```java javax.xml.bind.UnmarshalException - with linked exception: [org.xml.sax.SAXParseException; systemId: file:/C:/Users/lokesh/workspace/App/employee.xml; lineNumber: 7; columnNumber: 34; cvc-datatype-valid.1.2.1: 'Lokesh' is not a valid value for 'integer'.] at javax.xml.bind.helpers.AbstractUnmarshallerImpl.createUnmarshalException(AbstractUnmarshallerImpl.java:335) at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.createUnmarshalException(UnmarshallerImpl.java:563) at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:249) at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:214) at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:157) at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:162) at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:171) at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:189) at com.howtodoinjava.demo.JaxbExample.jaxbXmlFileToObject(JaxbExample.java:45) at com.howtodoinjava.demo.JaxbExample.main(JaxbExample.java:23) Caused by: org.xml.sax.SAXParseException; systemId: file:/C:/Users/lokesh/workspace/App/employee.xml; lineNumber: 7; columnNumber: 34; cvc-datatype-valid.1.2.1: 'Lokesh' is not a valid value for 'integer'. at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:203) at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:134) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:437) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:368) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:325) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator$XSIErrorReporter.reportError(XMLSchemaValidator.java:458) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.reportSchemaError(XMLSchemaValidator.java:3237) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.elementLocallyValidType(XMLSchemaValidator.java:3152) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.processElementContent(XMLSchemaValidator.java:3062) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.handleEndElement(XMLSchemaValidator.java:2140) at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.endElement(XMLSchemaValidator.java:859) at com.sun.org.apache.xerces.internal.jaxp.validation.ValidatorHandlerImpl.endElement(ValidatorHandlerImpl.java:584) at com.sun.xml.internal.bind.v2.runtime.unmarshaller.ValidatingUnmarshaller.endElement(ValidatingUnmarshaller.java:91) at com.sun.xml.internal.bind.v2.runtime.unmarshaller.SAXConnector.endElement(SAXConnector.java:165) at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:609) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1782) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2973) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:606) at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:117) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:848) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:777) at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141) at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1213) at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:649) at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:243) ... 7 more ``` 將我的問題放在評論部分。學習愉快！