在执行 JAXB 解组时处理无效的枚举值 [英] Handling invalid enum values while doing JAXB Unmarshalling
问题描述
我的 Jaxb 基于 XML 模式设置创建了一个 Enum 类.
My Jaxb has created a Enum class based on the XML schema set up.
**enum Fruit {
APPLE,ORANGE;
}**
我正在使用 SOAP UI 来检查我的 Web 服务.因为它是一个自由形式的条目，如果我给一个错误的水果说 "Guva" 那么它不会抛出异常，而是在执行 UnMarshalling 后将其返回为 null.
I am using a SOAP UI to check my web service. Since it is a free form entry, if i give a wrong fruit say "Guva" then instead of throwing an exception it is returning it as null after doing the UnMarshalling.
我怎样才能避免这种情况?我应该使用自定义枚举类而不是 JAXB 生成的.请举一些例子.即
How can i avoid this? Should i use custom enum class instead of JAXB generated one. Please give some example. i.e.
问候sri
推荐答案
注意:我是EclipseLink JAXB (MOXy) 领导者和 JAXB (JSR-222) 专家组.
Note: I'm the EclipseLink JAXB (MOXy) lead and a member of the JAXB (JSR-222) expert group.
默认情况下，您的 JAXB (JSR-222) 实现不会因任何转换异常而失败.如果您使用 JAXB API 进行解组，那么您可以设置一个 ValidationEventHandler 来捕获任何问题.下面是一个例子.
By default your JAXB (JSR-222) implementation will not fail on any conversion exceptions. If you are using the JAXB APIs to do the unmarshalling then you can set a ValidationEventHandler to catch any problems. Below is an example.
根
package forum12147306;
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement
public class Root {
private int number;
private Fruit fruit;
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}
public Fruit getFruit() {
return fruit;
}
public void setFruit(Fruit fruit) {
this.fruit = fruit;
}
}
水果
package forum12147306;
public enum Fruit {
APPLE,
ORANGE;
}
演示
package forum12147306;
import java.io.StringReader;
import javax.xml.bind.*;
public class Demo {
private static final String XML = "<root><number>ABC</number><fruit>Guva</fruit></root>";
public static void main(String[] args) throws Exception {
JAXBContext jc = JAXBContext.newInstance(Root.class);
Unmarshaller unmarshaller = jc.createUnmarshaller();
unmarshaller.setEventHandler(new ValidationEventHandler() {
@Override
public boolean handleEvent(ValidationEvent validationEvent) {
System.out.println(validationEvent.getMessage());
//validationEvent.getLinkedException().printStackTrace();
return true;
}
});
Root root = (Root) unmarshaller.unmarshal(new StringReader(XML));
}
}
JAXB 参考实现
不幸的是，JAXB RI 中似乎存在错误，因为无效枚举值的验证事件未通过.
Unfortunately there appears to be a bug in the JAXB RI as a validation event is not being through for the invalid enum value.
Not a number: ABC
解决方法
编写您自己的 XmlAdapter 来处理与 Fruit 枚举之间的转换:
Write your own XmlAdapter to handle to conversion to/from the Fruit enum:
水果适配器
package forum12147306;
import javax.xml.bind.JAXBException;
import javax.xml.bind.annotation.adapters.XmlAdapter;
public class FruitAdapter extends XmlAdapter<String, Fruit> {
@Override
public String marshal(Fruit fruit) throws Exception {
return fruit.name();
}
@Override
public Fruit unmarshal(String string) throws Exception {
try {
return Fruit.valueOf(string);
} catch(Exception e) {
throw new JAXBException(e);
}
}
}
水果
使用 @XmlJavaTypeAdapter 注释将 XmlAdapter 与 Fruit 枚举关联.
Use the @XmlJavaTypeAdapter annotation to associate the XmlAdapter with the Fruit enumb.
package forum12147306;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
@XmlJavaTypeAdapter(FruitAdapter.class)
public enum Fruit {
APPLE,
ORANGE;
}
新输出
Not a number: ABC
javax.xml.bind.JAXBException
- with linked exception:
[java.lang.IllegalArgumentException: No enum const class forum12147306.Fruit.Guva]
EclipseLink JAXB (MOXy)
使用 MOXy 会引发两个验证事件.要将 MOXy 指定为您的 JAXB 提供程序，请参阅:http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html.
Using MOXy both validation events are thrown. To specify MOXy as your JAXB provider see: http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html.
Exception Description: The object [ABC], of class [class java.lang.String], from mapping [org.eclipse.persistence.oxm.mappings.XMLDirectMapping[number-->number/text()]] with descriptor [XMLDescriptor(forum12147306.Root --> [DatabaseTable(root)])], could not be converted to [class java.lang.Integer].
Internal Exception: java.lang.NumberFormatException: For input string: "ABC"
Exception Description: No conversion value provided for the value [Guva] in field [fruit/text()].
Mapping: org.eclipse.persistence.oxm.mappings.XMLDirectMapping[fruit-->fruit/text()]
Descriptor: XMLDescriptor(forum12147306.Root --> [DatabaseTable(root)])
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