Struts 1.x Vs Struts 2.x
srinivas
excelent features are:
1. Servlet Dependency:
Actions in Struts1 have dependencies on the servlet API since the
HttpServletRequest and HttpServletResponse objects are passed to the
execute method when an Action is invoked but in case of Struts 2,
Actions are not container dependent because they are made simple
POJOs. In struts 2, the servlet contexts are represented as simple
Maps which allows actions to be tested in isolation. Struts 2 Actions
can access the original request and response, if required. However,
other architectural elements reduce or eliminate the need to access
the HttpServetRequest or HttpServletResponse directly.
2. Action classes
Programming the abstract classes instead of interfaces is one of
design issues of struts1 framework that has been resolved in the
struts 2 framework.
Struts1 Action classes needs to extend framework dependent abstract
base class. But in case of Struts 2 Action class may or may not
implement interfaces to enable optional and custom services. In case
of Struts 2 , Actions are not container dependent because they are
made simple POJOs. Struts 2 provides a base ActionSupport class to
implement commonly used interfaces. Albeit, the Action interface is
not required. Any POJO object with an execute signature can be used as
an Struts 2 Action object.
3. Validation
Struts1 and Struts 2 both supports the manual validation via a
validate method.
Struts1 uses validate method on the ActionForm, or validates through
an extension to the Commons Validator. However, Struts 2 supports
manual validation via the validate method and the XWork Validation
framework. The Xwork Validation Framework supports chaining validation
into sub-properties using the validations defined for the properties
class type and the validation context.
4. Threading Model
In Struts1, Action resources must be thread-safe or synchronized. So
Actions are singletons and thread-safe, there should only be one
instance of a class to handle all requests for that Action. The
singleton strategy places restrictions on what can be done with
Struts1 Actions and requires extra care to develop. However in case of
Struts 2, Action objects are instantiated for each request, so there
are no thread-safety issues. (In practice, servlet containers generate
many throw-away objects per request, and one more object does not
impose a performance penalty or impact garbage collection.)
5. Testability
Testing Struts1 applications are a bit complex. A major hurdle to test
Struts1 Actions is that the execute method because it exposes the
Servlet API. A third-party extension, Struts TestCase, offers a set of
mock object for Struts1. But the Struts 2 Actions can be tested by
instantiating the Action, setting properties and invoking methods.
Dependency Injection support also makes testing simpler. Actions in
struts2 are simple POJOs and are framework independent, hence
testability is quite easy in struts2.
6. Harvesting Input
Struts1 uses an ActionForm object to capture input. And all
ActionForms needs to extend a framework dependent base class.
JavaBeans cannot be used as ActionForms, so the developers have to
create redundant classes to capture input.
However Struts 2 uses Action properties (as input properties
independent of underlying framework) that eliminates the need for a
second input object, hence reduces redundancy. Additionally in
struts2, Action properties can be accessed from the web page via the
taglibs. Struts 2 also supports the ActionForm pattern, as well as
POJO form objects and POJO Actions. Even rich object types, including
business or domain objects, can be used as input/output objects.
7. Expression Language
Struts1 integrates with JSTL, so it uses the JSTL-EL. The struts1 EL
has basic object graph traversal, but relatively weak collection and
indexed property support. Struts 2 can also use JSTL, however it
supports a more powerful and flexible expression language called
"Object Graph Notation Language" (OGNL).
8. Binding values into views
In the view section, Struts1 uses the standard JSP mechanism to bind
objects (processed from the model section) into the page context to
access. However Struts 2 uses a "ValueStack" technology so that the
taglibs can access values without coupling your view to the object
type it is rendering. The ValueStack strategy allows the reuse of
views across a range of types which may have the same property name
but different property types.
9. Type Conversion
Usually, Struts1 ActionForm properties are all Strings. Struts1 uses
Commons-Beanutils for type conversion. These type converters are per-
class and not configurable per instance. However Struts 2 uses OGNL
for type conversion. The framework includes converters for basic and
common object types and primitives.
10. Control Of Action Execution
Struts1 supports separate Request Processor (lifecycles) for each
module, but all the Actions in a module must share the same lifecycle.
However Struts 2 supports creating different lifecycles on a per
Action basis via Interceptor Stacks. Custom stacks can be created and
used with different Actions as needed.