How to customize parameter names when binding Spring MVC command objects?

Question

I have a command object:

public class Job {     private String jobType;     private String location; } 

Which is bound by spring-mvc:

@RequestMapping("/foo") public String doSomethingWithJob(Job job) {    ... } 

Which works fine for http://example.com/foo?jobType=permanent&location=Stockholm. But now I need to make it work for the following url instead:

http://example.com/foo?jt=permanent&loc=Stockholm 

Obviously, I don't want to change my command object, because the field names have to remain long (as they are used in the code). How can I customize that? Is there an option to do something like this:

public class Job {     @RequestParam("jt")     private String jobType;     @RequestParam("loc")     private String location; } 

This doesn't work (@RequestParam can't be applied to fields).

The thing I'm thinking about is a custom message converter similar to FormHttpMessageConverter and read a custom annotation on the target object

Answer 1

This solution more concise but requires using RequestMappingHandlerAdapter, which Spring use when <mvc:annotation-driven /> enabled. Hope it will help somebody. The idea is to extend ServletRequestDataBinder like this:

 /**  * ServletRequestDataBinder which supports fields renaming using {@link ParamName}  *  * @author jkee  */ public class ParamNameDataBinder extends ExtendedServletRequestDataBinder {      private final Map<String, String> renameMapping;      public ParamNameDataBinder(Object target, String objectName, Map<String, String> renameMapping) {         super(target, objectName);         this.renameMapping = renameMapping;     }      @Override     protected void addBindValues(MutablePropertyValues mpvs, ServletRequest request) {         super.addBindValues(mpvs, request);         for (Map.Entry<String, String> entry : renameMapping.entrySet()) {             String from = entry.getKey();             String to = entry.getValue();             if (mpvs.contains(from)) {                 mpvs.add(to, mpvs.getPropertyValue(from).getValue());             }         }     } } 

Appropriate processor:

/**  * Method processor supports {@link ParamName} parameters renaming  *  * @author jkee  */  public class RenamingProcessor extends ServletModelAttributeMethodProcessor {      @Autowired     private RequestMappingHandlerAdapter requestMappingHandlerAdapter;      //Rename cache     private final Map<Class<?>, Map<String, String>> replaceMap = new ConcurrentHashMap<Class<?>, Map<String, String>>();      public RenamingProcessor(boolean annotationNotRequired) {         super(annotationNotRequired);     }      @Override     protected void bindRequestParameters(WebDataBinder binder, NativeWebRequest nativeWebRequest) {         Object target = binder.getTarget();         Class<?> targetClass = target.getClass();         if (!replaceMap.containsKey(targetClass)) {             Map<String, String> mapping = analyzeClass(targetClass);             replaceMap.put(targetClass, mapping);         }         Map<String, String> mapping = replaceMap.get(targetClass);         ParamNameDataBinder paramNameDataBinder = new ParamNameDataBinder(target, binder.getObjectName(), mapping);         requestMappingHandlerAdapter.getWebBindingInitializer().initBinder(paramNameDataBinder, nativeWebRequest);         super.bindRequestParameters(paramNameDataBinder, nativeWebRequest);     }      private static Map<String, String> analyzeClass(Class<?> targetClass) {         Field[] fields = targetClass.getDeclaredFields();         Map<String, String> renameMap = new HashMap<String, String>();         for (Field field : fields) {             ParamName paramNameAnnotation = field.getAnnotation(ParamName.class);             if (paramNameAnnotation != null && !paramNameAnnotation.value().isEmpty()) {                 renameMap.put(paramNameAnnotation.value(), field.getName());             }         }         if (renameMap.isEmpty()) return Collections.emptyMap();         return renameMap;     } } 

Annotation:

/**  * Overrides parameter name  * @author jkee  */  @Target(ElementType.FIELD) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface ParamName {      /**      * The name of the request parameter to bind to.      */     String value();  } 

Spring config:

<mvc:annotation-driven>     <mvc:argument-resolvers>         <bean class="ru.yandex.metrika.util.params.RenamingProcessor">             <constructor-arg name="annotationNotRequired" value="true"/>         </bean>     </mvc:argument-resolvers> </mvc:annotation-driven>  

And finally, usage (like Bozho solution):

public class Job {     @ParamName("job-type")     private String jobType;     @ParamName("loc")     private String location; }