javax.xml.bind.UnmarshalException - 与链接除外：[org.xml.sax.SAXParseException：内容未在序言中不允许的。]

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.... 

客户机代码：

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 - 与链接的异常： ： 在javax.xml.bind.helpers.AbstractUnmarshallerImpl.createUnmarshalException（AbstractUnmarshallerImpl [org.xml.sax.SAXParseException内容不允许在序言。]。 java：315） at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.createUnmarshalException（UnmarshallerImpl.java:526） at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0（ UnmarshallerImpl.java:223） at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal（UnmarshallerImpl.java:189） at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal（AbstractUnmarshallerImpl.java： 137） at javax.xml.bi nd.helpers.AbstractUnmarshallerImpl.unmarshal（AbstractUnmarshallerImpl.java:194） 在com.ge.dsp.iworkRemote.remoteAgents.CustomerRemoteAgent.getCustomerByCustNo（CustomerRemoteAgent.java:151） 在com.ge.dsp.iworkRemote.remoteAgents.CustomerRemoteAgent。执行（CustomerRemoteAgent.java:311） at com.ge.dsp.iworkRemote.remoteAgents.CustomerRemoteAgent.main（CustomerRemoteAgent.java:368） 原因：org.xml.sax.SAXParseException：在prolog中不允许使用内容。 at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException（Unknown Source） at org.apache.xerces.util.ErrorHandlerWrapper.fatalError（Unknown Source） at org.apache.xerces.impl.XMLErrorReporter.reportError（Unknown Source ） 在org.apache.xerces.impl.XMLErrorReporter.reportError（来源不明） 在org.apache.xerces.impl.XMLScanner.reportFatalError（来源不明） 在org.apache.xerces.impl.XMLDocumentScannerImpl $ PrologDispatcher.dispatch （Unknown Source） at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument（Unknown Source） at org.apache.xerces.parsers.XML11Configuration.parse（Unknown Source） at org.apache.xerces.parsers.XML11Configuration。解析（未知来源）（未知源） at org.apache.xerces.jaxp.SAXParserImpl $ JAXPSAXParser.parse（Unknown Source） 来源不明） 在com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0（UnmarshallerImpl.java:217） ... 6个 显示java.lang.NullPointerException 在com.ge.dsp.iworkRemote .remoteAgents.CustomerRemoteAgent.submitRequest（CustomerRemoteAgent.java:167） at com.ge.dsp.iworkRemote.remoteAgents.CustomerRemoteAgent.execute（CustomerRemoteAgent.java:313） at com.ge.dsp.iworkRemote.remoteAgents.CustomerRemoteAgent.main （CustomerRemoteAgent.java:368）

Answer 1

备注：我是EclipseLink JAXB (MOXy)的领导和JAXB (JSR-222)专家组的成员。

JAXB（JSR-222）规范不包含JSON绑定。当JAXB注释模型与JAX-RS实现一起使用时，会发生超出JAXB规范的处理。这就是为什么当你尝试使用标准的JAXB API来处理JSON消息时，你会得到一个XML解析器异常。

演示

的EclipseLink MOXY是JAXB实现，它提供了JSON结合（见：http://blog.bdoughan.com/2011/08/json-binding-with-eclipselink-moxy.html）的原生支持。下面是你的问题发布（加上访问器）

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使用您的域模型的例子

要使用莫西为您的JAXB提供者，你需要添加一个名为jaxb.properties文件相同的封装与下面的条目您的域模型（见：http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html）：

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

input.json /输出

{ 
    "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 " 
    } 
}