親愛的同學的java程序員一個抽象類的工作， 我用從http://www.vogella.com/articles/JAXB/article.html如何使與JAXB
爲JAXB XML使用一個例子我的3個班，UserStorage，用戶和UserTest
它工作正常，但它只是在線程「主要」 javax.xml.bind.UnmarshalException
JAXBContext context = JAXBContext.newInstance(UserStorage.class);
Marshaller m = context.createMarshaller();
m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
the User class is ABSTRACT!, so it throws an
異常的unmarchialing：無法 創建instan用戶 - 帶有鏈接的異常：[com.un.InstantiationException] at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.handleEvent（UnmarshallingContext.java:648） at com。 sun.xml.internal.bind.v2.runtime.unmarshaller.Loader.reportError（Loader.java:236） at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.createInstance（UnmarshallingContext.java ：615） at com.sun.xml.internal.bind.v2.runtime.unmarshaller.StructureLoader.startElement（StructureLoader.java:170） at com.sun.xml.internal.bind.v2.runtime.unmarshaller .UnmarshallingContext._startElement（UnmarshallingContext.java:487） at com.sun .xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.startElement（UnmarshallingContext.java:465） at com.sun.xml.internal.bind.v2.runtime.unmarshaller.SAXConnector.startElement（SAXConnector.java： 135） 在 com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement（AbstractSAXParser.java:501） 在 com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement（ XMLNSDocumentScannerImpl.java:400） 在 com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl $ FragmentContentDriver.next（XMLDocumentFragmentScannerImpl.java:2756） 在 com.sun.org.apache.xerces.internal。 impl.XMLDocumentScannerImpl.next（XMLDocumentScannerImpl.jav一：648） 在 com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next（XMLNSDocumentScannerImpl.java:140） 在 com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl。 scanDocument（XMLDocumentFragmentScannerImpl.java:511） 在 com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse（XML11Configuration.java:808） 在 com.sun.org.apache.xerces.internal。 parsers.XML11Configuration.parse在 com.sun.org.apache.xerces.internal.parsers.XMLParser.parse（XMLParser.java:119）（XML11Configuration.java:737） 在 com.sun.org.apache。 xerces.internal.parsers.AbstractSAXParser.parse（AbstractSAXPars er.java:1205） at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl $ JAXPSAXParser.parse（SAXParserImpl.java:522） at com.sun.xml.internal.bind.v2。 runtime.unmarshaller.UnmarshallerImpl.unmarshal0（UnmarshallerImpl.java:200） 在 com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal（UnmarshallerImpl.java:173） 在 javax.xml。 bind.helpers.AbstractUnmarshallerImpl.unmarshal（AbstractUnmarshallerImpl.java:137） 在 javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal（AbstractUnmarshallerImpl.java:194） 在platform.UserTest.main（UserTest.java:77）引起通過： java.lang。InstantiationException在 sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance（InstantiationExceptionConstructorAccessorImpl.java:30） 在java.lang.reflect.Constructor.newInstance（Constructor.java:513） 在 com.sun.xml.internal.bind.v2。 ClassFactory.create0（ClassFactory.java:112） at com.sun.xml.internal.bind.v2.runtime.ClassBeanInfoImpl.createInstance（ClassBeanInfoImpl.java:231）at com.sun.xml.internal.bind.v2 .runtime.unmarshaller.UnmarshallingContext.createInstance（UnmarshallingContext.java:609） ...... 20多個
對此有任何解決方案，所以我可以將用戶類綁定到XML，因爲我可以用用戶詳細信息保存XML文件，但是當我想要檢索它時，它會認爲用戶類是抽象的，我有管理員，經紀人，股東子類，但到目前爲止，在我的用戶測試課上，我只創建了4個管理員進行測試，感謝並希望您能提供幫助。
import platform.UserStorage;
import platform.User;
public class UserTest {
private static final String USER_XML = "user2.xml";
public static void main(String[] args) throws JAXBException, IOException {
ArrayList<User> userList = new ArrayList<User>();
// create test users
User user1 = new Admin();
user1.setName("Dave");
user1.setPass("1234");
user1.setDeleted(true);
user1.setBan(false);
userList.add(user1);
User user2 = new Admin();
user2.setName("James");
user2.setPass("1234");
user2.setDeleted(true);
user2.setBan(false);
userList.add(user2);
User user3 = new Admin();
user3.setName("Mike");
user3.setPass("1234");
user3.setDeleted(true);
user3.setBan(false);
userList.add(user3);
// create bookstore, assigning book
UserStorage userstore = new UserStorage();
userstore.setListName("Test List");
userstore.setUserList(userList);
// create JAXB context and instantiate marshaller
JAXBContext context = JAXBContext.newInstance(UserStorage.class);
Marshaller m = context.createMarshaller();
m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
m.marshal(userstore, System.out);
Writer w = null;
try {
w = new FileWriter(USER_XML);
m.marshal(userstore, w);
} finally {
try {
w.close();
} catch (Exception e) {
}
}
// get variables from our xml file, created before
System.out.println();
System.out.println("Output from our XML File: ");
Unmarshaller um = context.createUnmarshaller();
UserStorage userstore2 = (UserStorage) um.unmarshal(new FileReader(
USER_XML));
for (int i = 0; i < userstore2.getUsersList().toArray().length; i++) {
System.out.println("User " + (i + 1) + ": "
+ userstore2.getUsersList().get(i).getName() + " Pass "
+ userstore2.getUsersList().get(i).getPass());
}} }
package platform;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;
//If you want you can define the order in which the fields are written
//Optional
/**
* @author dinesh.kaushish, james.wyche //updated XML properties.
*
*/
@XmlRootElement(name = "user")
@XmlType(propOrder = { "name", "pass", "deleted", "ban" })
..
public abstract class User implements UserInterface {
private String name;
private String pass;
private boolean deleted;
private boolean ban;
/**
* @ author dinesh.kaushish
* @param String username
* return void
*/
public void setName(String name)
{
this.name = name;
}
// If you like the variable name, e.g. "name", you can easily change this
// name for your XML-Output:
/**
* @author dinesh.kaushish
* @param null
* @return String user;
*/
@XmlElement(name = "user")
public String getName()
{
return this.name;
}
/**
* @author dinesh.kaushish
* @param String pwd
* @return void
*/
public void setPass(String pass)
{
this.pass=pass;
}
/**
* @author dinesh.kaushish
* @param void
* @return String password
*/
@XmlElement(name = "pass")
public String getPass()
{
return pass;
}
/**
* @author dinesh.kaushish
* @param dFlag
* @return void
*/
public void setDeleted(boolean deleted)
{
this.deleted = deleted;
}
/**
* @author dinesh.kaushish
* @return boolean isDeleted
*/
@XmlElement(name = "deleted")
public boolean getDeleted()
{
return deleted;
}
/**
* @author dinesh.kaushish
* @param bFlag
*/
public void setBan(boolean ban)
{
this.ban = ban;
}
/**
* @author dinesh.kaushish
* @return Boolean isBanned
*/
@XmlElement(name = "ban")
public Boolean getBan()
{
return ban;
}
public abstract void addUser();
public abstract void removeUser();
public abstract void verifyUser();
public abstract void passReset();
public abstract void faultReport();
public abstract void RequestsForAccess();
public abstract void UpdateDetails();
public abstract void BanUser();
public abstract void ChangePermissions();
}
package platform;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.HashMap;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.events.XMLEvent;
import java.util.ArrayList;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementWrapper;
import javax.xml.bind.annotation.XmlRootElement;
/**
* @author michael.wambeek, james.wyche //added JAXB support.
*
*/
//This statement means that class "Bookstore.java" is the root-element of our example
@XmlRootElement(namespace = "platform")
public class UserStorage {
// XmLElementWrapper generates a wrapper element around XML representation
@XmlElementWrapper(name = "userList")
// XmlElement sets the name of the entities
@XmlElement(name = "user")
private ArrayList<User> userList;
private String listName = "";
//私有靜態UserStorage實例; //結束james.wyche JAXB代碼。
public UserStorage(){
}
/**
* @author michael.wambeek
*
* Searches for a username and returns the password.
*
* @param username The username to search for
* @return The password of the correct username or null
* @throws Exception
*/
public String findUser(String username) throws Exception{
return search(username);
}
public boolean storeUser(String username, String password, UserType type){
return true;
}
/**
* @author james.wyche
* @param userList
*/
public void setUserList(ArrayList<User> userList) {
this.userList = userList;
}
/**
*
* @return UserList
*/
public ArrayList<User> getUsersList() {
return userList;
}
的超類會清除可能不是所希望的繼承關係添加XmlTransient，請參閱：http://blog.bdoughan.com/搜索/標籤/ XmlTransient。豐滿文章可能會有所幫助：http://blog.bdoughan.com/2010/11/jaxb-and-inheritance-using-xsitype.html – 2012-04-22 12:53:06
謝謝，請看看 – Sean 2012-04-22 13:44:06