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• Use OGNL expressions - the framework will automatically take care of creating the actual objects for you.
• Use JavaBeans! The framework can only create objects that obey the JavaBean specification, provide no-arg constructions and include getters and setters where appropriate.
• Remember that person.name will call getPerson().setName(). If the framework creates the Person object for you, it remember that a setPerson method must also exist.
• The framework will not instantiate an object if an instance already exists. The PrepareInterceptor or action's constructor can be used to create target objects before type conversion.
• Wiki MarkupFor lists and maps, use index notation, such as _people\[0\].name_ or _friends\['patrick'\].name_. Often these HTML form elements are being rendered inside a loop. For [JSP Tags], use the iterator tag's status attribute. For [FreeMarker Tags], use the special property $\{foo_index\}\[\].
• For multiple select boxes, it isn't possible to use index notation to name each individual item. Instead, name your element people.name and the framework will understand that it should create a new Person object for each selected item and set its name accordingly.

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The framework automatically converts the type of the parameter sent in to the type of the key property using type conversion.

Wiki MarkupUnlike Map and List element properties, if {{fooCollection(22)}} does not exist, it will not be created. If you would like it created, use the notation {{fooCollection.makeNew\[index\]}} where _index_ is an integer 0, 1, and so on. Thus, parameter value pairs {{fooCollection.makeNew\[0\]=Phil}} and {{fooCollection.makeNew\[1\]=John}} would add two new Foo Objects to {{fooCollection \ -\-}} one with name property value {{Phil}} and the other with name property value {{John}}. However, in the case of a Set, the {{equals}} and {{hashCode}} methods should be defined such that they don't only include the {{id}} property. Otherwise, one element of the null {{id}} properties Foos to be removed from the Set.

An advanced example for indexed Lists and Maps

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• When submitting this via a form, the id value is used as KeyProperty for the MyBean instances in the beanList.

• Wiki MarkupNotice the () notation\! Do not use \ [\] notation, which is for Maps only\!

• The value for name will be set to the MyBean instance with this special id.

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