`@ XmlRootElement`和`nillable` [英] `@XmlRootElement` and `nillable`
问题描述
有什么方法可以让JAXB在可操作的@XmlRootElement
上正确打印xmlns:xsi
和xsi:nill
吗?
Is there any way to let JAXB properly prints xmlns:xsi
and xsi:nill
on nillable @XmlRootElement
?
public class XmlValueTest {
public static void main(final String[] args) throws JAXBException {
final JAXBContext context =
JAXBContext.newInstance(Wrapper.class, Value.class);
final Marshaller marshaller = context.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
marshaller.marshal(Value.newInstance(null), System.out);
marshaller.marshal(Value.newInstance("null"), System.out);
marshaller.marshal(Wrapper.newInstance(null), System.out);
marshaller.marshal(Wrapper.newInstance("null"), System.out);
}
}
@XmlAccessorType(XmlAccessType.NONE)
@XmlRootElement
class Value {
public static Value newInstance(final String raw) {
final Value instance = new Value();
instance.raw = raw;
return instance;
}
@XmlValue
private String raw;
}
@XmlAccessorType(XmlAccessType.NONE)
@XmlRootElement
class Wrapper {
public static Wrapper newInstance(final String raw) {
final Wrapper wrapper = new Wrapper();
wrapper.raw = raw;
return wrapper;
}
@XmlElement(nillable = true, required = true)
private String raw;
}
打印
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<value/> <!-- is this normal? -->
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<value>null</value>
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<wrapper>
<raw xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
</wrapper>
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<wrapper>
<raw>null</raw>
</wrapper>
我只是想知道有什么办法让第一个<value/>
装备有xmlns:xsi
和xsi:nill
.
I just want to know is there any way to let the first <value/>
armed with xmlns:xsi
and xsi:nill
.
推荐答案
注意:我是 EclipseLink JAXB(MOXy) 的负责人,以及
Note: I'm the EclipseLink JAXB (MOXy) lead, and a member of the JAXB (JSR-222) expert group.
我不认为有一种使用标准JAXB API来实现此目的的方法.下面是一个示例,可以通过将@XmlElement(nillable=true)
与@XmlPath("text()")
结合使用来获得所需的行为.
I do not believe that there is a way to do this using the standard JAXB APIs. Below is an example where it can be done by leveraging @XmlElement(nillable=true)
with @XmlPath("text()")
to get the desired behaviour.
值
package forum11796699;
import javax.xml.bind.annotation.*;
import org.eclipse.persistence.oxm.annotations.XmlPath;
@XmlRootElement
public class Value {
private String value;
@XmlElement(nillable=true)
@XmlPath("text()")
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
}
jaxb.properties
要将MOXy指定为JAXB提供程序,您需要在与域模型相同的软件包中包含一个名为jaxb.properties
的文件,并带有以下条目(请参阅:
To specify MOXy as your JAXB provider you need to have a file called jaxb.properties
in the same package as your domain model with the following entry (see: http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html):
javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory
演示
package forum11796699;
import javax.xml.bind.*;
public class Demo {
public static void main(String[] args) throws Exception {
JAXBContext jc = JAXBContext.newInstance(Value.class);
Value value = new Value();
value.setValue(null);
Marshaller marshaller = jc.createMarshaller();
marshaller.marshal(value, System.out);
}
}
输出
<?xml version="1.0" encoding="UTF-8"?>
<value xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>
这篇关于`@ XmlRootElement`和`nillable`的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!