Using JDK's JAXB without ns2 prefix

问题:

After having read all posts about this on Oracle forums, Stackoverflow, java.net I'm finally posting here. I'm using JAXB to create XML files but the problem is that it adds the famous ns2 prefix before my elements, I have tried all the solutions no one worked for me. java -version gives "1.6.0_37"

Solution 1 : Using package-info.java

I created the file in my package containing my @Xml* annotated classes with the following content :

@XmlSchema(
    namespace = "http://mynamespace",
    elementFormDefault = XmlNsForm.QUALIFIED,
    xmlns = {
        @XmlNs(namespaceURI = "http://mynamespace", prefix = "")
    }
)
package com.mypackage;
import javax.xml.bind.annotation.XmlNs;
import javax.xml.bind.annotation.XmlNsForm;
import javax.xml.bind.annotation.XmlSchema;

Solution 2 : NamespacePrefixMapper

I created the following class and set the mapper to the marshaller :

// Change mapper to avoid ns2 prefix on generated XML
class PreferredMapper extends NamespacePrefixMapper {
    @Override
    public String getPreferredPrefix(String namespaceUri, String suggestion, boolean requirePrefix) {
        return "";
    }
}
NamespacePrefixMapper mapper = new PreferredMapper();
try {
    marshaller.setProperty("com.sun.xml.bind.namespacePrefixMapper", mapper);
}
catch (PropertyException e) {
   logger.info("No property for com.sun.xml.bind.namespacePrefixMapper found : " + e.getMessage());
}

With com.sun.xml.bind.namespacePrefixMapper nothing happens, with com.sun.xml.internal.bind.namespacePrefixMapper, it throws the exception.

I've also addded the maven dependency in my pom, but it seems that JRE version has a higher priority :

<dependency>
    <groupId>com.sun.xml.bind</groupId>
    <artifactId>jaxb-impl</artifactId>
    <version>2.2.4</version>
</dependency>

Can you help me on this ?

PS : I can't include directly the jar in my classpath for build reasons. PS2 : I can't use JDK7. Thanks in advance.

回答1:

Without the implementation of MOXy is not possible. JAXB if the preferred prefix is "", it generates a new one.

I had the same problem in the past, and I configured each prefix for each package-info.java.

NamespacePrefixMapper says in JAVADOC

null if there's no prefered prefix for the namespace URI.
In this case, the system will generate a prefix for you.

Otherwise the system will try to use the returned prefix,
but generally there's no guarantee if the prefix will be
actually used or not.

return "" to map this namespace URI to the default namespace.
Again, there's no guarantee that this preference will be
honored.

If this method returns "" when requirePrefix=true, the return
value will be ignored and the system will generate one"

else if use package-info

we know we can't bind to "", but we don't have any possible name at hand.
generate it here to avoid this namespace to be bound to "".

I hope I've given you all the answers about your question.

回答2:

I had the same problem today. The production machine has Java 6 and when I deployed my application, I was getting the ns2 prefix. This is how I resolved it. Production server has only Java 1.6 patch 21

1. I made sure that I have a package-info.java file in my package where all the classes were generated using Jaxb. I checked it and the @XmlSchema was all auto generated, so I didn't mess with any of that. Don't use namespacemapper, that just confused me.

2. In my pom.xml file, I added jaxb-impl dependency: com.sun.xml.bind jaxb-impl 2.2.5-b04

   and specified source and target as 1.6. Did a maven clean install and package and deployed into production, everything looks good. Next step is to make sure that production machine is upgraded to Java 7. Hope this helps :)