How to configure JAXB so it trims whitespaces by default

Question

I would like to configure JAXB so that it trims whitespaces on all string fields

I saw the following answer : How to configure JAXB so it trims whitespaces when unma

Answer 1

1. Create a XmlAdapter.

   package com.foo.bar;
   public class StringTrimAdapter extends XmlAdapter<String, String> {
       @Override
       public String unmarshal(String v) throws Exception {
           if (v == null)
               return null;
           return v.trim();
       }
       @Override
       public String marshal(String v) throws Exception {
           if (v == null)
               return null;
           return v.trim();
       }
   }
   

2. Create a package-info.java file in com.foo.bar.

3. Add the following to the package-info.java file

   @XmlJavaTypeAdapter(value=StringTrimAdapter.class,type=String.class)
   package com.foo.bar;
   import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
   

4. This will apply StringTrimAdapter to all String fields in com.foo.bar without any extra annotations.

EDIT
Do note that if the package level annotation is too expansive for you, you could always apply a @XmlJavaTypeAdapter annotation to classes.

Answer 2

To make the example of configuring XJC (in the answer provided by Lukas Eder) complete, i would like to add the following sample configuration which we need to add in maven's pom.xml

    <build>
    .
    .
    <execution>
       <id>responseSchema</id>
       <goals>
          <goal>xjc</goal>
       </goals>
       <phase>generate-sources</phase>
       <configuration>
          <clearOutputDir>false</clearOutputDir>
          <outputDirectory>${project.basedir}/src/main/java</outputDirectory>
          <packageName>com.foo.bar.domain.response</packageName>
          <bindingFiles>../resources/bindings.xjb</bindingFiles>
          <schemaDirectory>${project.basedir}/src/main/resources/wsdl/xsd</schemaDirectory>
          <schemaFiles>response.xsd</schemaFiles>
          <extension>true</extension>
       </configuration>
    </execution>
    .
    .
 </build>

We need to have the following content to be added in bindings.xjb.

<jaxb:globalBindings>
    <xjc:javaType 
         name="java.lang.String" 
         xmlType="xs:string" 
         adapter="com.foo.bar.StringTrimAdapter"/>
</jaxb:globalBindings>

Answer 3

It might be worth mentioning, that in addition to writing an XmlAdapter, which performs the trimming, you can configure XJC to actually use this adapter in generated code. An example of how to do it:

<jaxb:globalBindings>
    <xjc:javaType 
         name="java.lang.String" 
         xmlType="xs:string" 
         adapter="com.foo.bar.StringTrimAdapter"/>
</jaxb:globalBindings>

The above example uses the XmlAdapter given in Sahil's answer