Best ways to perform server-side validation based on data using Java

Question

Can someone help me on this fundamental question: What are the best ways to do server side validation on data using Java?

I would like to know if there are open source libraries available for server side validation.

Any help is appreciated.

Answer 1

It depends on what kind of web development framework you are using.

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JSP Servlet Gray

If you use a simple jsp servlet, then I would suggest adding one validation package / banner for each screen of the / jsp form. and confirm it from the controller before proceeding with service.

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Jsf

If you use JSF, then there is a very well-designed validation phase, you can use ready-made validators (you can simply add the annotation to the form field and its execution), or you can also create your own validators.

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Spring mvc

If you use Spring MVC, it also has a saperate layer for validation .

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Spacers

Struts also got a saperate level to test

Answer 2

If you want to check POJO, you can take a look at the Oval structure http://oval.sourceforge.net/

JSR-303 (and its implementation) can also help if ur application is developed based on pojos or beans

Here is an example of a custom check in OVal: Let's say you need to check the variable map in SomeValueClass and make sure that the welcome key is always present.

public class SomeValueClass { @FormCollection Map variables; public static void main(String[] args) { SomeValueClass svc1 = new SomeValueClass(); svc1.variables = new HashMap(); svc1.variables.put("greeting", ""); Validator validator = new Validator(); List<ConstraintViolation> violations = validator.validate(svc1); System.out.println("svc1 violations.size() = " + violations.size()); } 

@FormCollection annotations on "Variable maps"; is a regular validator and looks like this:

 @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD}) @net.sf.oval.configuration.annotation.Constraint(checkWith = FormCollectionCheck.class) public @interface FormCollection { String message() default "Some errors in the form"; } 

And the constraint check class will look like this:

 public class FormCollectionCheck extends AbstractAnnotationCheck<FormCollection> { public boolean isSatisfied(Object validatedObject, Object valueToValidate, OValContext context, Validator validator) { Map vars = (Map) valueToValidate; return !(vars.get("greeting")==null || ((String)vars.get("greeting")).length()<=0); } } 

Hope this helps, Greetings

Answer 3

then you go on to an infrastructure that provides built-in checks such as racks, etc. This will give you a validation component. It also opens.