How to retrieve data from DB and print in jsp using spring and hibernate? - spring

Question

I have already written the code for inserting my data into my DB but I'm a bit confused on how to retrieve that data in json format and print in my jsp view using a jQuery data table. I have written some code on retrieving but I'm still stuck. Please help.
Here are my code snippets:
entity class:
package model.entity;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import javax.validation.constraints.Size;
#Entity
public class Products {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int productId;
#Size(min=1)
private String productName;
#Min(value=1, message = "Value cannot be zero or negative")
private double unitPrice;
#Size(min=1)
private String productDescription;
#Size(min=1)
private String category;
#Min(value = 1, message = " Quantity should be greater than zero and positive")
#Max(value= 99, message = " Quantity limit exceeded, value should be less than 100")
private int productQty;
public Products() {}
public Products(int productId, String productName, double unitPrice, String productDescription, String category, int productQty) {
super();
this.productQty = productQty;
this.productId = productId;
this.productName = productName;
this.unitPrice = unitPrice;
this.productDescription = productDescription;
this.category = category;
}
public int getProductQty() {
return productQty;
}
public void setProductQty(int productQty) {
this.productQty = productQty;
}
public int getProductId() {
return productId;
}
public void setProductId(int productId) {
this.productId = productId;
}
public String getProductName() {
return productName;
}
public void setProductName(String productName) {
this.productName = productName;
}
public double getUnitPrice() {
return unitPrice;
}
public void setUnitPrice(double unitPrice) {
this.unitPrice = unitPrice;
}
public String getProductDescription() {
return productDescription;
}
public void setProductDescription(String productDescription) {
this.productDescription = productDescription;
}
public String getCategory() {
return category;
}
public void setCategory(String category) {
this.category = category;
}
DAOImplementation class:
package model.daoimpl;
import java.util.List;
import org.hibernate.Session;
import model.config.HibernateUtil;
import model.dao.IProductsDAO;
import model.entity.Products;
public class ProductsDAOImpl implements IProductsDAO {
private Session sess;
public ProductsDAOImpl() {
sess = HibernateUtil.getSessionFactory().openSession();
}
public boolean insertProduct(Products p) {
boolean b = true;
try
{
sess.beginTransaction();
sess.save(p);
sess.getTransaction().commit();
}catch(Exception ex)
{
b = false;
sess.getTransaction().rollback();
ex.printStackTrace();
}
return b;
}
public List<Products> getProducts()
{
List<Products> lp = null;
try
{
sess.beginTransaction();
lp = sess.createQuery("from Product",Products.class).getResultList();
}catch(Exception ex)
{
ex.printStackTrace();
}
return lp;
}
}
controller class:
#Controller
public class ProductController {
#RequestMapping(value="/manageproducts", method= RequestMethod.GET)
public String manageProductPage() {
return "manageproducts";
}
#RequestMapping(value="/insertproducts",method = RequestMethod.POST)
public String addInserProductsPage(#ModelAttribute("Products")Products p) {
IProductsDAO ip = new ProductsDAOImpl();
boolean b = ip.insertProduct(p);
if(b)
return "success";
else
return "manageproducts";
}
#RequestMapping(value="/listproducts", method = RequestMethod.GET)
public List<Products> listAllProducts(){
IProductsDAO ip = new ProductsDAOImpl();
return ip.getProducts();
}
}
So as you can see I have created the getproducts function but I haven't created the view for displaying products for which I want to use the jQuery datatable, Also I'm a bit confused on how to map the view with my controller. So please help.

Answer 1

You can use Model to send your list to the view page
#RequestMapping(value="/listproducts", method = RequestMethod.GET)
public String listAllProducts(Model model){
IProductsDAO ip = new ProductsDAOImpl();
List<Products> products = ip.getProducts();
model.addAttribute ("products",products);
Return "your view name without .jsp";
}