javax.xml.bind.UnmarshalException - 带有链接异常：[org.xml.sax.SAXParseException：prolog 中不允许内容。]

Question

Customer.java

@Entity
@Table(name = "CUSTOMER", uniqueConstraints =
{
 @UniqueConstraint(columnNames =
{
    "CUSTNO"
})
})
@XmlRootElement
public class Customer
    implements Serializable
{
/**
 * 
 */
private static final long serialVersionUID = 1L;

@Id @Column(name = "CUSTNO", length = 10, nullable = false) private String            custNo;

@Column(name = "TITLE", length = 20, nullable = false) private String                 title;

@Column(name = "FIRSTNAME", length = 20, nullable = false) private String             
firstName;

@Column(name = "MIDINIT", length = 1, nullable = true) private String                 
midInit;

@Column(name = "LASTNAME", length = 1, nullable = false) private String               
lastName;

@Column(name = "EMAIL", length = 50, nullable = false) private String                 
email;

@Column(name = "PHONE", length = 16, nullable = true) private String                  
phone;

@Column(name = "GENDER", length = 1, nullable = true) private String                  
gender;

@Column(name = "STREETADDRESS", length = 50, nullable = true) private String          
streetAddress;

@Column(name = "CITY", length = 20, nullable = true) private String                   
city;

@Column(name = "STATE", length = 2, nullable = true) private String                    
state;

@Column(name = "ZIPCODE", length = 10, nullable = true) private String                
zipCode;

@Column(name = "COMPANYNAME", length = 25, nullable = true) private String            
companyName;

@OneToMany(fetch = FetchType.LAZY, mappedBy = "customer") private Set<ServiceRequest> 
requests;

public Customer()
{

}
...... getters/setters....

客户端代码：

byte[] getCustomerResponse = (byte[])    
RestClientUtil.sendGetMethod(urlGetCustomer + URLEncoder.encode(custNo, "UTF-8"));
Unmarshaller unmarshaller = RestClientUtil.getUnmarshaller(Customer.class);
StringReader reader = new StringReader(new String(getCustomerResponse));

Customer customer = (Customer) unmarshaller.unmarshal(reader);

我看到输出为：

found customer :{"customer":{"city":"city1         ","companyName":"companyName1            ","custNo":"RCN1","email":"email1@ge.com","firstName":"first1                   ","gender":"F","lastName":"last1                    ","midInit":"K","phone":"4082229871      ","state":"CA","streetAddress":"streetAddress1","title":"S   ","zipCode":"zipCode   "}}

javax.xml.bind.UnmarshalException - 有关联的例外： [org.xml.sax.SAXParseException：序言中不允许内容。] 在 javax.xml.bind.helpers.AbstractUnmarshallerImpl.createUnmarshalException（AbstractUnmarshallerImpl.java:315） 在 com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.createUnmarshalException（UnmarshallerImpl.java:526） 在 com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:223) 在 com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:189) 在 javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal（AbstractUnmarshallerImpl.java:137） 在 javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal（AbstractUnmarshallerImpl.java:194） 在 com.ge.dsp.iworkRemote.remoteAgents.CustomerRemoteAgent.getCustomerByCustNo(CustomerRemoteAgent.java:151) 在 com.ge.dsp.iworkRemote.remoteAgents.CustomerRemoteAgent.execute(CustomerRemoteAgent.java:311) 在 com.ge.dsp.iworkRemote.remoteAgents.CustomerRemoteAgent.main(CustomerRemoteAgent.java:368) 原因：org.xml.sax.SAXParseException：prolog 中不允许内容。 在 org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException（未知来源） 在 org.apache.xerces.util.ErrorHandlerWrapper.fatalError（未知来源） 在 org.apache.xerces.impl.XMLErrorReporter.reportError（未知来源） 在 org.apache.xerces.impl.XMLErrorReporter.reportError（未知来源） 在 org.apache.xerces.impl.XMLScanner.reportFatalError（未知来源） 在 org.apache.xerces.impl.XMLDocumentScannerImpl$PrologDispatcher.dispatch（未知来源） 在 org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument（未知来源） 在 org.apache.xerces.parsers.XML11Configuration.parse（未知来源） 在 org.apache.xerces.parsers.XML11Configuration.parse（未知来源） 在 org.apache.xerces.parsers.XMLParser.parse（未知来源） 在 org.apache.xerces.parsers.AbstractSAXParser.parse（未知来源） 在 org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse（未知来源） 在 com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:217) ... 6 更多 java.lang.NullPointerException 在 com.ge.dsp.iworkRemote.remoteAgents.CustomerRemoteAgent.submitRequest(CustomerRemoteAgent.java:167) 在 com.ge.dsp.iworkRemote.remoteAgents.CustomerRemoteAgent.execute(CustomerRemoteAgent.java:313) 在 com.ge.dsp.iworkRemote.remoteAgents.CustomerRemoteAgent.main(CustomerRemoteAgent.java:368)

Answer 1

注意：我是EclipseLink JAXB (MOXy) 领导，也是JAXB (JSR-222) 专家组的成员。

JAXB (JSR-222) 规范不包括 JSON 绑定。当 JAXB 注释模型与 JAX-RS 实现一起使用时，会出现超出 JAXB 规范的处理。这就是为什么当您尝试使用标准 JAXB API 来处理 JSON 消息时会收到 XML 解析器异常。

演示

EclipseLink MOXy 是一个 JAXB 实现，它提供对 JSON 绑定的本机支持（请参阅：http://blog.bdoughan.com/2011/08/json-binding-with-eclipselink-moxy.html）。以下是使用您的问题中发布的域模型的示例（添加了访问器）

package forum13652303;

import java.io.File;
import java.util.*;
import javax.xml.bind.*;
import org.eclipse.persistence.jaxb.JAXBContextProperties;

public class Demo {

    public static void main(String[] args) throws Exception {
        Map<String, Object> properties = new HashMap<String, Object>(1);
        properties.put(JAXBContextProperties.MEDIA_TYPE, "application/json");
        JAXBContext jc = JAXBContext.newInstance(new Class[] {Customer.class}, properties);

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File json = new File("src/forum13652303/input.json");
        Customer customer = (Customer) unmarshaller.unmarshal(json);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(customer, System.out);
    }

}

jaxb.properties

要将 MOXy 用作您的 JAXB 提供程序，您需要在与域模型相同的包中添加一个名为 jaxb.properties 的文件，并使用以下条目（请参阅：http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html）：

javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory

input.json/Output

{
   "customer" : {
      "city" : "city1 ",
      "companyName" : "companyName1 ",
      "custNo" : "RCN1",
      "email" : "email1@ge.com",
      "firstName" : "first1 ",
      "gender" : "F",
      "lastName" : "last1 ",
      "midInit" : "K",
      "phone" : "4082229871 ",
      "state" : "CA",
      "streetAddress" : "streetAddress1",
      "title" : "S ",
      "zipCode" : "zipCode "
   }
}