Custom Mappings Via Dozer XML Files

This section will cover setting up custom mappings in xml file(s). If the two different types of data objects that you are mapping contain any fields that don't share a common property name, you will need to add a class mapping entry to your custom mapping xml file. These mappings xml files are used at runtime by the Dozer mapping engine.

Dozer automatically performs any type conversion when copying the source field data to the destination field. The Dozer mapping engine is bi-directional, so if you wanted to map the destination object to the source object, you do not need to add another class mapping to the xml file.

An example of a mapping file....

         
<?xml version="1.0" encoding="UTF-8"?>
<mappings xmlns="http://dozer.sourceforge.net"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://dozer.sourceforge.net
          http://dozer.sourceforge.net/schema/beanmapping.xsd">
          
  <mapping> 
    <class-a>org.dozer.vo.TestObject</class-a>
    <class-b>org.dozer.vo.TestObjectPrime</class-b>   
    <field>
      <a>one</a>
      <b>onePrime</b>
    </field>
  </mapping>  

  <mapping wildcard="false"> 
    <class-a>org.dozer.vo.TestObjectFoo</class-a>
    <class-b>org.dozer.vo.TestObjectFooPrime</class-b>   
      <field>
        <a>oneFoo</a>
        <b>oneFooPrime</b>
      </field>
  </mapping>  

</mappings> 
      

A mappings element has multiple mapping elements, each with class mapping declarations and field level mappings. The wildcard attribute is set to true by default. This means that it will automatically try to map every property in the two objects. When the attribute is set to false it will only map explicitly defined fields.

IMPORTANT: Properties that are of the same name do not need to be specified in the mapping xml file. Dozer automatically maps all fields with the same property name from the source object into the destination object.

How Custom Mapping Files Are Loaded

Dozer will search the entire classpath looking for the specified file. The generally acceptable way of distributing your mappings is to bundle them inside your application archive.

Alternatively, you can load files from outside the classpath by prepending "file:" to the resource name. Ex) "file:c:\somedozermapping.xml"

Loading Files from Input Stream

Since version 5.4.0 it is possible to load XML mapping files from provided InputStream object. Check DozerMapper class for the corresponding API calls.