Java 如何在JAXB中设置无名称空间的nil和数据类型属性
我将JAXB与Scala一起使用,我的编组代码如下所示:Java 如何在JAXB中设置无名称空间的nil和数据类型属性,java,scala,jaxb,Java,Scala,Jaxb,我将JAXB与Scala一起使用,我的编组代码如下所示: def marshalToXml(): String = { val context = JAXBContext.newInstance(this.getClass()) val writer = new StringWriter context.createMarshaller.marshal(this, writer) writer.toString() } 然后,对于我的可空元素,我使用注释@xmlement(ni
def marshalToXml(): String = {
val context = JAXBContext.newInstance(this.getClass())
val writer = new StringWriter
context.createMarshaller.marshal(this, writer)
writer.toString()
}
然后,对于我的可空元素,我使用注释@xmlement(nillable=true)
,如所示。这将为我提供如下XML输出:
<name>Alex Dean</name>
<customerReference xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
<quantity>1</quantity>
<createdAt>2011-05-14T00:00:00+03:00</createdAt>
亚历克斯·迪恩
1.
2011-05-14T00:00:00+03:00
这是一个良好的开端,但我真正想为这些字段封送的是:
<name>Alex Dean</name>
<customerReference nil="true"/>
<quantity type="integer">1</quantity>
<createdAt type="datetime">2011-05-14T00:00:00+03:00</createdAt>
亚历克斯·迪恩
1.
2011-05-14T00:00:00+03:00
换句话说,我希望删除名称空间属性和前缀,并为除字符串以外的所有对象添加显式XML数据类型属性。这可能非常简单,但我似乎无法在JAXB文档中找到如何实现
感谢您的帮助 您可以将JAXB与StAX解析器一起使用,并执行以下操作: 客户 域模型中的每个属性都将映射为
@xmlement(nillable=true,type=Object.class)
。设置type=Object.class
将强制写出xsi:type
属性
package forum8198945;
import java.util.Date;
import javax.xml.bind.annotation.*;
@XmlRootElement
public class Customer {
private String name;
private Customer customerReference;
private Integer quantity;
private Date createdAt;
@XmlElement(nillable=true, type=Object.class)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@XmlElement(nillable=true, type=Object.class)
public Customer getCustomerReference() {
return customerReference;
}
public void setCustomerReference(Customer customerReference) {
this.customerReference = customerReference;
}
@XmlElement(nillable=true, type=Object.class)
public Integer getQuantity() {
return quantity;
}
public void setQuantity(Integer quantity) {
this.quantity = quantity;
}
@XmlElement(nillable=true, type=Object.class)
public Date getCreatedAt() {
return createdAt;
}
public void setCreatedAt(Date createdAt) {
this.createdAt = createdAt;
}
}
xmlStreamWriterRapper
我们将为XMLStreamWriter
编写一个创建包装器的程序,该程序将删除我们不希望写入XML的所有信息
package forum8198945;
import javax.xml.namespace.NamespaceContext;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;
public class XMLStreamWriterWrapper implements XMLStreamWriter {
private XMLStreamWriter xmlStreamWriter;
public XMLStreamWriterWrapper(XMLStreamWriter xmlStreamWriter) {
this.xmlStreamWriter = xmlStreamWriter;
}
public void writeStartElement(String localName) throws XMLStreamException {
xmlStreamWriter.writeStartElement(localName);
}
public void writeStartElement(String namespaceURI, String localName) throws XMLStreamException {
xmlStreamWriter.writeStartElement(namespaceURI, localName);
}
public void writeStartElement(String prefix, String localName, String namespaceURI) throws XMLStreamException {
xmlStreamWriter.writeStartElement(prefix, localName, namespaceURI);
}
public void writeEmptyElement(String namespaceURI, String localName) throws XMLStreamException {
xmlStreamWriter.writeEmptyElement(namespaceURI, localName);
}
public void writeEmptyElement(String prefix, String localName, String namespaceURI) throws XMLStreamException {
xmlStreamWriter.writeEmptyElement(prefix, localName, namespaceURI);
}
public void writeEmptyElement(String localName) throws XMLStreamException {
xmlStreamWriter.writeEmptyElement(localName);
}
public void writeEndElement() throws XMLStreamException {
xmlStreamWriter.writeEndElement();
}
public void writeEndDocument() throws XMLStreamException {
xmlStreamWriter.writeEndDocument();
}
public void close() throws XMLStreamException {
xmlStreamWriter.close();
}
public void flush() throws XMLStreamException {
xmlStreamWriter.flush();
}
public void writeAttribute(String localName, String value) throws XMLStreamException {
xmlStreamWriter.writeAttribute(localName, value);
}
public void writeAttribute(String prefix, String namespaceURI, String localName, String value) throws XMLStreamException {
if("http://www.w3.org/2001/XMLSchema-instance".equals(namespaceURI)) {
int colonIndex = value.indexOf(':');
if(colonIndex > -1) {
value = value.substring(colonIndex + 1);
}
xmlStreamWriter.writeAttribute(localName, value);
} else {
xmlStreamWriter.writeAttribute(prefix, namespaceURI, localName, value);
}
}
public void writeAttribute(String namespaceURI, String localName, String value) throws XMLStreamException {
if("http://www.w3.org/2001/XMLSchema-instance".equals(namespaceURI)) {
int colonIndex = value.indexOf(':');
if(colonIndex > -1) {
value = value.substring(colonIndex + 1);
}
xmlStreamWriter.writeAttribute(localName, value);
} else {
xmlStreamWriter.writeAttribute(namespaceURI, localName, value);
}
}
public void writeNamespace(String prefix, String namespaceURI) throws XMLStreamException {
if(!"http://www.w3.org/2001/XMLSchema-instance".equals(namespaceURI) && !"http://www.w3.org/2001/XMLSchema".equals(namespaceURI)) {
xmlStreamWriter.writeNamespace(prefix, namespaceURI);
}
}
public void writeDefaultNamespace(String namespaceURI) throws XMLStreamException {
if(!"http://www.w3.org/2001/XMLSchema-instance".equals(namespaceURI)) {
xmlStreamWriter.writeDefaultNamespace(namespaceURI);
}
}
public void writeComment(String data) throws XMLStreamException {
// TODO Auto-generated method stub
}
public void writeProcessingInstruction(String target) throws XMLStreamException {
// TODO Auto-generated method stub
}
public void writeProcessingInstruction(String target, String data) throws XMLStreamException {
// TODO Auto-generated method stub
}
public void writeCData(String data) throws XMLStreamException {
// TODO Auto-generated method stub
}
public void writeDTD(String dtd) throws XMLStreamException {
// TODO Auto-generated method stub
}
public void writeEntityRef(String name) throws XMLStreamException {
// TODO Auto-generated method stub
}
public void writeStartDocument() throws XMLStreamException {
xmlStreamWriter.writeStartDocument();
}
public void writeStartDocument(String version) throws XMLStreamException {
xmlStreamWriter.writeStartDocument(version);
}
public void writeStartDocument(String encoding, String version) throws XMLStreamException {
xmlStreamWriter.writeStartDocument(encoding, version);
}
public void writeCharacters(String text) throws XMLStreamException {
xmlStreamWriter.writeCharacters(text);
}
public void writeCharacters(char[] text, int start, int len) throws XMLStreamException {
xmlStreamWriter.writeCharacters(text, start, len);
}
public String getPrefix(String uri) throws XMLStreamException {
return xmlStreamWriter.getPrefix(uri);
}
public void setPrefix(String prefix, String uri) throws XMLStreamException {
xmlStreamWriter.setPrefix(prefix, uri);
}
public void setDefaultNamespace(String uri) throws XMLStreamException {
xmlStreamWriter.setDefaultNamespace(uri);
}
public void setNamespaceContext(NamespaceContext context) throws XMLStreamException {
xmlStreamWriter.setNamespaceContext(context);
}
public NamespaceContext getNamespaceContext() {
return xmlStreamWriter.getNamespaceContext();
}
public Object getProperty(String name) throws IllegalArgumentException {
return xmlStreamWriter.getProperty(name);
}
}
xmlStreamReaderRapper
我们需要为XMLStreamReader
创建一个包装器,它添加了我们在XMLStreamWriter
上剥离的所有内容。这对于XMLStreamReader
更容易做到,因为我们可以扩展StreamReaderDelegate
package forum8198945;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.util.StreamReaderDelegate;
public class XMLStreamReaderWrapper extends StreamReaderDelegate {
public XMLStreamReaderWrapper(XMLStreamReader xmlStreamReader) {
super(xmlStreamReader);
}
@Override
public String getAttributeNamespace(int index) {
String attributeName = getAttributeLocalName(index);
if("type".equals(attributeName) || "nil".equals(attributeName)) {
return "http://www.w3.org/2001/XMLSchema-instance";
}
return super.getAttributeNamespace(index);
}
}
演示
以下内容演示了所有内容是如何组合在一起的:
package forum8198945;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.Date;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamWriter;
public class Demo {
public static void main(String[] args) throws Exception {
JAXBContext jc = JAXBContext.newInstance(Customer.class);
Customer customer = new Customer();
customer.setName("Alex Dean");
customer.setCustomerReference(null);
customer.setQuantity(1);
customer.setCreatedAt(new Date());
StringWriter stringWriter = new StringWriter();
XMLOutputFactory xof = XMLOutputFactory.newFactory();
XMLStreamWriter xsw = xof.createXMLStreamWriter(stringWriter);
xsw = new XMLStreamWriterWrapper(xsw);
Marshaller marshaller = jc.createMarshaller();
marshaller.marshal(customer, xsw);
String xml = stringWriter.toString();
System.out.println(xml);
XMLInputFactory xif = XMLInputFactory.newFactory();
xif.createXMLStreamReader(new StringReader(xml));
printValue(customer.getName());
printValue(customer.getCustomerReference());
printValue(customer.getQuantity());
printValue(customer.getCreatedAt());
}
private static void printValue(Object value) {
System.out.print(value);
System.out.print(" ");
if(null != value) {
System.out.print(value.getClass());
}
System.out.println();
}
}
输出
<?xml version="1.0"?><customer><createdAt type="dateTime">2011-11-25T13:36:49.095</createdAt><customerReference nil="true"></customerReference><name type="string">Alex Dean</name><quantity type="int">1</quantity></customer>
Alex Dean class java.lang.String
null
1 class java.lang.Integer
Fri Nov 25 13:36:49 EST 2011 class java.util.Date
2011-11-25T13:36:49.095Alex Dean1
Alex Dean类java.lang.String
无效的
1类java.lang.Integer
2011年11月25日星期五13:36:49东部标准时间class java.util.Date
非常感谢Blaise-这非常有效。Scala用户需要注意的是,type
注释的Scala等价语法是:@XmlElement(`type`=classOf[Object])
。我还想问一下xmlStreamReaderRapper
——因为我看不出这是如何连接到演示中的解组器中的?