How to store java objects in mysql using jpa? - mysql

Question

I have converted the JSON into POJO using GSON.
I am looking to store Employee entity object into mysql using JPA's save() method. But I am getting an error saying "cannot determine the type for Address". So how should I go with this?
Here is the error:
Could not determine type for : Address
Employee.java
package com.example.demo;
import java.math.BigDecimal;
import java.util.Map;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import com.google.gson.annotations.Expose;
#Entity
public class Employee {
#Id
private int id;
private String name;
private int age;
private BigDecimal salary;
private String designation;
private Address address;
private long[] phoneNumbers;
/*Getter and Setter Methods*/
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public BigDecimal getSalary() {
return salary;
}
public void setSalary(BigDecimal salary) {
this.salary = salary;
}
public String getDesignation() {
return designation;
}
public void setDesignation(String designation) {
this.designation = designation;
}
public long[] getPhoneNumbers() {
return phoneNumbers;
}
public void setPhoneNumbers(long[] phoneNumbers) {
this.phoneNumbers = phoneNumbers;
}
public Address getAddress() {
return address;
}
public void setAddress(Address address) {
this.address = address;
}
}
Address.java
package com.example.demo;
import javax.persistence.Entity;
import javax.persistence.Id;
//#Entity
public class Address {
#Id
private String street;
private String city;
private int zipCode;
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public int getZipCode() {
return zipCode;
}
public void setZipcode(int zipcode) {
this.zipCode = zipcode;
}
#Override
public String toString(){
return getStreet() + ", "+getCity()+", "+getZipCode();
}
}
Controller Class
package com.example.demo;
import net.sf.json.*;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.ResponseBody;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonObject;
import net.sf.json.JSONObject;
#Controller // This means that this class is a Controller
#RequestMapping(path="/demo") // This means URL's start with /demo
(after Application path)
public class MainController {
#Autowired // This means to get the bean called userRepository
// Which is auto-generated by Spring, we will use it
to handle the data
private UserRepository userRepository;
#GetMapping(path="/add") // Map ONLY GET Requests
public #ResponseBody String addNewUser (#RequestBody String json) {
// #ResponseBody means the returned String is the response, not a view name
// #RequestParam means it is a parameter from the GET or POST request
//JSONObject jsonObject = JSONObject.fromObject(json);
Gson gson=new GsonBuilder().create();
Employee employee =gson.fromJson(json,Employee.class);
userRepository.save(employee);
return "Successfully added to database using JPA!";
}
#GetMapping(path="/all")
public #ResponseBody Iterable<Employee> getAllUsers() {
// This returns a JSON or XML with the users
return userRepository.findAll();
}
}

Answer 1

Try adding implements Serializable for your Entity classes.
ie.
#Entity
public class Employee implements Serializable{
}

Answer 2

Whenever you use #Entity annotation in your class and trying to save its instance in database. At very intially a create table command is formed in hibernate which creates table in the database with the given specifications. As in employee table you specify the datatypes of all data-members. When cursor come to 'Address', it gave error because hibernate not able to find any datatype related this or any table related this.
As you commented #Entity annoatation in Address class. So no table regarding that will be created in database.
Address is class reference for this hibernate need the class(table). As class(table) is not there ,so the error comes.