Want to automatically insert current Date in the table When a post Request is made - date

Question

I have a User Entity and an Order Entity.
One of the field in order entity is date.
Till now i have the user enter the date.
Now i want that at the time post request is made the date is automatically set to the current date and stored in the database.
Tried using #Prepersist annotation But since this is my first API that i am developing using springBoot , I don't really know how to use it.
User Entity
#Entity
public class User {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private BigInteger id;
#NotEmpty(message = "Name is compulsory")
#Pattern(regexp="^[A-Za-z]*[A-Za-z-'. ]*[A-Za-z]*$",message = "Name has invalid characters")
private String username;
//#NotEmpty(message = "Phone Number is compulsary")
#Range(min = 6400000000L ,max=9999999999L)
private Long phoneNumber;
#NotEmpty(message = "Address is compulsary")
private String address;
public User(){}
public User(BigInteger id, String username, Long phoneNumber, String address) {
super();
this.id = id;
this.username = username;
this.phoneNumber = phoneNumber;
this.address = address;
}
public BigInteger getId() {
return id;
}
public void setId(BigInteger id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Long getPhoneNumber() {
return phoneNumber;
}
public void setPhoneNumber(Long phoneNumber) {
this.phoneNumber = phoneNumber;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
Order Entity
#Entity
public class Orders {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private BigInteger id;
#CreationTimestamp
#Temporal(TemporalType.TIMESTAMP)
private Date date;
#ManyToOne
private User user;
public Orders(){}
public Orders(BigInteger id, Date date,BigInteger userId) {
super();
this.id = id;
this.date = date;
this.user=new User(userId," ",0000000000L," ");
}
public BigInteger getId() {
return id;
}
public void setId(BigInteger id) {
this.id = id;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
}
Order Controller
#RestController
public class OrdersController {
#Autowired
private OrdersService ordersService;
#ApiOperation(value="Show all orders")
#RequestMapping("/orders")
public Iterable<Orders> getAllOrders()
{
return ordersService.getAllOrders();
}
#ApiOperation(value="Show a particular Order")
#RequestMapping("/orders/{orderId}")
public Orders getOrderById(#PathVariable BigInteger orderId)
{
return ordersService.getOrderById(orderId);
}
#ApiOperation(value="Show all orders of a particular User")
#RequestMapping("/users/{id}/orders")
public List<Orders> getOrders(#PathVariable BigInteger id) {
return ordersService.getOrders(id);
}
#ApiOperation(value="Show an order for a User")
#RequestMapping("/users/{userId}/orders/{id}")
public Orders getOrder(#PathVariable BigInteger id){
return ordersService.getOrder(id);
}
#ApiOperation(value="Adds a new Order")
#RequestMapping(method = RequestMethod.POST,value = "/users/{userId}/orders")
public Orders addOrder(#PathVariable BigInteger userId,#RequestBody Orders orders) {
orders.setUser(new User(userId," ",0000000000L," "));
return ordersService.addOrder(orders);
}
#ApiOperation(value="Alter an Order")
#RequestMapping(method = RequestMethod.PUT, value="/users/{userId}/orders/{id}")
public Orders updateOrder(#RequestBody Orders order,#PathVariable BigInteger id,#PathVariable BigInteger userId)throws Exception {
order.setUser(new User(userId," ",0000000000L," "));
return ordersService.updateOrder(order, id);
}
#ApiOperation(value="Delete an Order")
#RequestMapping(method = RequestMethod.DELETE, value="/orders/{id}")
public void deleteOrder(#PathVariable BigInteger id){
ordersService.deleteOrder(id);
}
}

Answer 1

#PrePersist is a JPA annotation and therefore should work in all compatible persistence frameworks. It indicates a method that should be invoked on particular entity lifecycle event. (Other events are well documented in the Hibernate user guide here).
Add this to your entity:
#Temporal(TemporalType.TIMESTAMP)
#Column(nullable = false)
private Date timestamp;
#PrePersist
private void onCreate() {
timestamp = new Date();
}
As for assigning/creating the entity in the controller, it is a good practice to use DTO (data transfer objects) in your controller (#RequestBody OrderDto orderDto) and then use some method to populate a new entity instance with those values. Most common options are
modelmapper
manually
...
Order o = new Order();
o.user = userDao.findById(orderDto.getUserId());
...
// persist o