Struts 2 validation by built-in validators

✔ STRUTS 2 CHAPTERS:-

1. Struts2 Overview
2. Struts2 Architecture
3. Struts2 Configuration Files
4. Action in Struts2
5. Action in Struts2 by using Pojo Class
6. Action in struts2 by Implementing Action Interface
7. Action in Struts2 by Extending Action Support Class
8. Struts2 Hello World Example
9. Multiple Configuration File in Struts2
10. OGNL in Struts2
11. Value Stack in Struts2
12. Interceptors in Struts2
13. Struts2 Execandwait Interceptor
14. Struts2 Custom Interceptor
15. Struts2 Result type
16. Struts2 Redirect result type
17. Struts2 Validation Framework
18. Struts2 Validation by Built in validators
19. Struts2 i18n
20. Struts2 Zero Configuration by convention approach
21. Struts2 Zero Configuration by annotation Approach
22. Dispatch Action Functionality in Struts2
23. Dynamic method invocation in Struts2
24. Struts2 UI Tags
25. Struts2 Control Tags
26. Struts2 Data Tags
27. Struts2 and tiles integration
28. Struts2 and Quartz2 Schedular
29. Struts2 Interview Questions and Answers

Struts 2 validation framework provides many generic built-in validators to perform various validations like email validation, required validation, stringlength validation etc. These validations are also known as XML based validation. Built-in validators are placed in an xml file. The name of the xml file should be like actionClassName-validation.xml.

Note: No need to specify any validate() method in the action class.

Types of validators in struts 2.

1. Field Validators.
2. Non-field validators.

1. Field validators:

These validators act or perform validations on the single field i.e. field validators are not generic they are specific to the single field. More than one validator can be applied to one field.

Syntax:

<validators>  
  <field name="fieldName">  
    <field-validator type="validatorName">  
      <message>message string</message>  
    </field-validator>  
  </field>  
</validators>

2. Non-field validators:

These validators are the action level validators. Single validator can be applied to multiple fields.

Note: In this approach only one validator can be applied to a single field.

Syntax:

<validators>  
  <validator type=" validatorName ">  
    <param name="fieldName">username</param>  
    <message> message string </message>  
  </validator>  
</validators>

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