Milos - Sort Order

Milos - Sort ORder

1. Update the form for sorting drop-down list

To pass the sortfield, we give a named parameter: "thesortfield". Also, update the options to use the same field names as our Hibernate entities. The form also includes a submit button to send data to the controller.

			<form action="${pageContext.request.contextPath}/customer/list">

				<select name="thesortfield">
				  <option value="firstName">First Name</option>
				  <option value="lastName">Last Name</option>
				  <option value="email">Email</option>
				  <option value="dateOfBirth">Date</option>
				</select>

				<input type="submit" value="Search" />
			</form>



2. Update the Controller to read the sort field

Use @RequestParam to read form field, "thesortfield". Use "firstName" as a default if none provided.

	@GetMapping(value="/list")
	public String listCustomers(@RequestParam(value="thesortfield",
			  							defaultValue = "firstName") String theSortField,
								Model theModel) {
		
		//get customers from service
		List<Customer> theCustomers = customerService.getCustomersBy(theSortField);
		
		//add the customers to the model
		//"customers" is the name (we use that in for loop to print data, theCustomers is the value that we got in lane above
		theModel.addAttribute("customers", theCustomers);

		return "list-customers";
		
	}


3. Update CustomerService with new method to handle sort field

Add a new method to handle sort field

File: CustomerService.java

	public List<Customer> getCustomersBy(String theSortField);


File: CustomerServiceImpl.java

	@Transactional
	public List<Customer> getCustomersBy(String theSortField) {
	
		return customerDAO.getCustomersBy(theSortField);
	}



4. Update CustomerDAO to perform the search using the sort field


File: CustomerDAO.java

	public List<Customer> getCustomersBy(String theSortField);


File: CustomerDAOImpl.java

	public List<Customer> getCustomersBy(String theSortField) {
		
		Session currentSession = sessionFactory.getCurrentSession();
		
		Criteria theCriteria = 
				currentSession.createCriteria(Customer.class)
				.addOrder(Order.asc(theSortField));
		
		//the method getResultList() is undefined for the type Criteria
		
		List<Customer> customers = theCriteria.list();
		
		return customers;			
	}


Latest code is available here (code only, no jars)

http://www.luv2code.com/temp/milos-sort-web-customer-tracker-source-only.zip