Build URL to display a case using case number instead of Salesforce CaseID

This can be implemented using below code.

Custom label:  
Name: Case_Number_Details

Value: Please enter the valid 8 character Case Number (e.g. 00123456) after the equal sign in the URL above to view the case details.

Visualforce Page:

<apex:page controller="GetCaseByNumber" title="Get Case By Number" showHeader="false">

  <script>

      if ("{!CaseQuery}".length > 0) {

          if ("{!CaseQuery}" != "<apex:outputText value="{!$Label.Case_Number_Details}"/>" && "{!CaseQuery}" != "You Must Supply a Case Number") window.location = "/{!CaseQuery}";

      }

  </script>

  <h1 style="display:block;margin:25px;font-size:16px;">{!CaseQuery}</h1>

</apex:page>

Apex Class:

public class GetCaseByNumber {

    public static String getCaseQuery () {

       String caseNumberDetails = Label.Case_Number_Details;

        string caseNumber = ApexPages.CurrentPage().getParameters().get('CaseNumber');

        List <Case> c = [SELECT Id FROM Case Where CaseNumber =: caseNumber];

        if (c.size()>0) {

            return string.valueOf(c[0].Id);

        }

        else return caseNumberDetails;

    }    

}

Apex test Class:

private class GetCaseByNumberTest {

    

    static testmethod void TestAccdata(){ 

        Profile prof = [select id from profile where name='System Administrator'];    

        User us      = new User(alias = 'tuser', email='TestUser@testingorg.com',    

                                emailencodingkey='UTF-8', lastname='TestingUser', languagelocalekey='en_US', 

                                localesidkey='en_US', profileid = prof.Id,   

                                timezonesidkey='America/Los_Angeles', username='TestUser@testingorg.com');

        insert us;  

        System.runAs (us) { 

            Account ac = new Account(Name    ='Test', OwnerId  =us.Id);            

            insert ac;

            

            

            Contact cn  = new Contact (FirstName  = 'Test', LastName = 'Test',AccountId = ac.Id,email='testcase@org.com');

            insert cn;

            

            Test.startTest();

            string RTID = [select id from RecordType where SobjectType = 'Case' and Name = 'Support Case'].Id;

            System.assertNotEquals(null,RTID);

            

            case c = new Case(AccountId=ac.Id ,ContactId =  cn.Id,Status='New',Origin='Phone',RecordTypeId = RTID,Subject = 'TestCase',Description ='Test',Product_Type__c = 'My Product);

            

            insert c;

            PageReference myVfPage = Page.getCaseByNumber;

            Test.setCurrentPage(myVfPage);

           ApexPages.currentPage().getParameters().put('CaseNumber',ApexPages.currentPage().getParameters().get(c.CaseNumber));

            

            GetCaseByNumber controller = new GetCaseByNumber();

            GetCaseByNumber.getCaseQuery();

            

            Test.stopTest();

            

        }

    }