我从在同一个项目中为我工作的相同 xml 开发了以下 xml。但是当我试图解组这些时，我得到了 NullPointerException。
我将我所有的 java 类与我正在解组的 xml 一起放置。
请帮忙
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<dbSchema>
<table tableName="table1">
<column columnName="column1">
<dataType>varchar</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
<isPrimaryKey>true</isPrimaryKey>
</column>
<column columnName="column2">
<dataType>timestamp</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column3">
<dataType>varchar</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column4">
<dataType>decimal</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column5">
<dataType>integer</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column6">
<dataType>varchar2</dataType>
<isNullAllowed>false</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column7">
<dataType>date</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column8">
<dataType>decimal</dataType>
<isNullAllowed>false</isNullAllowed>
<defaultValue></defaultValue>
</column>
</table>
<table tableName="table2">
<column columnName="column1">
<dataType>varchar</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
<isPrimaryKey>true</isPrimaryKey>
</column>
<column columnName="column2">
<dataType>timestamp</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column3">
<dataType>varchar</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column4">
<dataType>decimal</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column5">
<dataType>integer</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column6">
<dataType>varchar2</dataType>
<isNullAllowed>false</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column7">
<dataType>date</dataType>
<isNullAllowed>true</isNullAllowed>
<defaultValue></defaultValue>
</column>
<column columnName="column8">
<dataType>decimal</dataType>
<isNullAllowed>false</isNullAllowed>
<defaultValue></defaultValue>
</column>
</table>
</dbSchema>
@XmlRootElement(name="dbSchema")
public class DBSchema {
private Vector<Table> tableList;
/**
* @return the tableList
*/
public Vector<Table> getTableList() {
return tableList;
}
/**
* @param tableList the tableList to set
*/
//XmLElementWrapper generates a wrapper element around XML representation
//@XmlElementWrapper(name = "tableList")
//XmlElement sets the name of the entities
@XmlElement(name = "table")
public void setTabelList(Vector<Table> tableList) {
this.tableList = tableList;
}
}
@XmlRootElement(name = "table")
public class Table {
private String tableName;
private Vector<Column> columnList;
public Table() {
// TODO Auto-generated constructor stub
}
/**
* @return the tableName
*/
public String getTableName() {
return tableName;
}
/**
* @param pageId the pageId to set
*/
@XmlAttribute(name="tableName")
public void setTableName(String tableName) {
this.tableName = tableName;
}
/**
* @return the columnList
*/
public Vector<Column> getColumnList() {
return columnList;
}
/**
* @param columnList the columnList to set
*/
//XmLElementWrapper generates a wrapper element around XML representation
//@XmlElementWrapper(name = "columnList")
//XmlElement sets the name of the entities
@XmlElement(name = "column")
public void setColumnList(Vector<Column> columnList) {
this.columnList = columnList;
}
}
@XmlRootElement(name = "column")
public class Column {
private String columnName = "";
private String dataType = "";
private boolean isNullAllowed = false;
private boolean isPrimaryKey = false;
private String defaultValue = "";
public Column() {
// TODO Auto-generated constructor stub
}
/**
* @return the columnName
*/
public String getColumnName() {
return columnName;
}
/**
* @param columnName the columnName to set
*/
@XmlAttribute
public void setColumnName(String columnName) {
this.columnName = columnName;
}
/**
* @return the dataType
*/
public String getDataType() {
return dataType;
}
/**
* @param dataType the dataType to set
*/
@XmlElement
public void setDataType(String dataType) {
this.dataType = dataType;
}
/**
* @return the isNullAllowed
*/
public boolean isNullAllowed() {
return isNullAllowed;
}
/**
* @param isNullAllowed the isNullAllowed to set
*/
@XmlElement
public void setIsNullAllowed(boolean isNullAllowed) {
this.isNullAllowed = isNullAllowed;
}
/**
* @return the isPrimaryKey
*/
public boolean isPrimaryKey() {
return isPrimaryKey;
}
/**
* @param isPrimaryKey the isPrimaryKey to set
*/
@XmlElement
public void setIsPrimaryKey(boolean isPrimaryKey) {
this.isPrimaryKey = isPrimaryKey;
}
/**
* @return the defaultValue
*/
public String getDefaultValue() {
return defaultValue;
}
/**
* @param defaultValue the defaultValue to set
*/
@XmlElement
public void setDefaultValue(String defaultValue) {
this.defaultValue = defaultValue;
}
}
Exception in thread "main" java.lang.NullPointerException
at com.sun.xml.internal.bind.v2.runtime.reflect.Lister$CollectionLister.addToPack(Lister.java:290)
at com.sun.xml.internal.bind.v2.runtime.reflect.Lister$CollectionLister.addToPack(Lister.java:254)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.Scope.add(Scope.java:106)
at com.sun.xml.internal.bind.v2.runtime.property.ArrayERProperty$ReceiverImpl.receive(ArrayERProperty.java:195)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallingContext.endElement(UnmarshallingContext.java:524)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.SAXConnector.endElement(SAXConnector.java:143)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endElement(AbstractSAXParser.java:601)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEndElement(XMLDocumentFragmentScannerImpl.java:1782)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2939)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:648)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:140)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:511)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:808)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:119)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:200)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:173)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:137)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:142)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:151)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:169)
at com.misys.importexportdata.helpers.SQLHandler.readDBDefinition(SQLHandler.java:99)
at com.misys.importexportdata.helpers.SQLHandler.main(SQLHandler.java:29)
private void readDBDefinition() {
List<String> schemaList = FileHandler.getDirectoryContent(DefinedConstants.DB_DEFINITION_LOCATION);
for (int i = 0; i < schemaList.size(); i++ ) {
DBSchema schemaDetails = null;
String schemaName = schemaList.get(i) ;
if(schemaName.endsWith(".xml")) {
try {
JAXBContext context = JAXBContext.newInstance(DBSchema.class);
Unmarshaller unMarshaller = context.createUnmarshaller();
File dbDefinitionFile = new File(DefinedConstants.DB_DEFINITION_LOCATION + schemaName);
schemaDetails = (DBSchema) unMarshaller.unmarshal(dbDefinitionFile);
} catch (JAXBException e) {
e.printStackTrace();
}
}
tableMap.put(schemaName, schemaDetails.getTableList());
}
}
我得到的 Stacktrace 是这样结束的：
java.lang.NullPointerException
at com.sun.xml.bind.v2.runtime.reflect.Lister$CollectionLister.addToPack(Lister.java:305)
at com.sun.xml.bind.v2.runtime.reflect.Lister$CollectionLister.addToPack(Lister.java:269)
at com.sun.xml.bind.v2.runtime.unmarshaller.Scope.add(Scope.java:121)
at com.sun.xml.bind.v2.runtime.property.ArrayERProperty$ReceiverImpl.receive(ArrayERProperty.java:213)
at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallingContext.endElement(UnmarshallingContext.java:538)
at com.sun.xml.bind.v2.runtime.unmarshaller.ValidatingUnmarshaller.endElement(ValidatingUnmarshaller.java:107)
at com.sun.xml.bind.v2.runtime.unmarshaller.SAXConnector.endElement(SAXConnector.java:158)
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.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:258)
at com.sun.xml.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:229)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:140)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:123)
at org.springframework.oxm.jaxb.Jaxb2Marshaller.unmarshal(Jaxb2Marshaller.java:754)
at org.springframework.oxm.jaxb.Jaxb2Marshaller.unmarshal(Jaxb2Marshaller.java:735)
更新 1： SQLHandler 是具有 main 方法的 java 类。
更新2：伙计们，我发现了问题。这个问题非常愚蠢。我把注释拼错了。这导致了问题。