Auto data-binding Java object without Spring MVC

Question

I am developing a Java web project and not applying Spring MVC, Spring web-flow to it (because it is quite simple). I have a small problem when attaching value from HTTP request to Java object. Is there any standalone library or utility support us to bind data from client request to a server object automatically (matched by property name) without using Spring? Assume that parameters in client request had already built to a map.
When I work with Grails (a web framework for Groovy), it has a very awesome way to fill data in request parameter to object by using: object.properties=parameters , but I do not know that in Java, do we have a similar mechanism to implement it?
Thank you so much.

Answer 1

Apache Commons might help with BeanUtilsBean . It has cool methods like getProperty() and setProperty() , which might help if you wanna try to code it by hand using reflection. There's also the populate(Object bean, Map properties) method, which, i believe, is the closest to what you want.

Dozer is a java library specialized in mapping stuff from one structure to other. It might help.

This guy posted a similar question on coderanch and, after some discussion, he came up with the following:

public static <T extends Object> T setFromMap(Class<T> beanClazz, HashMap<String, String> propValues) throws Exception  
{  
    T bean = (T) beanClazz.newInstance();  
    Object obj = new Object();  
    PropertyDescriptor[] pdescriptors = null;  
    BeanInfo beanInfo = Introspector.getBeanInfo(beanClazz);  
    pdescriptors = beanInfo.getPropertyDescriptors();  
    for(int i=0; i<pdescriptors.length; i++)  
    {  
        String descriptorName = pdescriptors[i].getName();  
        if(!(descriptorName.equals("class")))  
        {  
            String propName = descriptorName;  
            String value = (String) propValues.get(propName);  
            if(value != null)  
            {  
                Object[] objArray = new Object[1];  
                objArray[0] = value;  
                Method writeMethod = pdescriptors[i].getWriteMethod();  
                writeMethod.invoke(bean, objArray);  
            }  
        }  
    }
    return bean;
}