Create a Post for a User Implementing The POST Service

Implementation of Creating A Post For Specific Users

 

To create a post for a specific user, we shall allow post-operation in this area.
 

Step 1: Creating data Entities

• Create User and Post class and @Entity annotation to represent these as a model/entity.

 

• Add getters and setters to the User and Post class.

 

• Add toString() method to the User and Post class. (Optional but better to have)
  
   

User.java

package com.example.codingninjas;

import javax.persistence.*;

@Entity
public class User {
  @Id
  @GeneratedValue(strategy= GenerationType.AUTO)
  private Integer id;

  private String firstName;

  private String lastName;

  private String email;

  private String address;

  //default constructor
  protected User() {

  }

  public User(Integer id, String firstName, String lastName, String email, String address) {
      super();
      this.id = id;
      this.firstName = firstName;
      this.lastName = lastName;
      this.email = email;
      this.address = address;
  }


  public Integer getId() {
      return id;
  }


  public void setId(Integer id) {
      this.id = id;
  }


  public String getFirstName() {
      return firstName;
  }


  public void setFirstName(String firstName) {
      this.firstName = firstName;
  }


  public String getLastName() {
      return lastName;
  }


  public void setLastName(String lastName) {
      this.lastName = lastName;
  }


  public String getEmail() {
      return email;
  }

  public void setEmail(String email) {
      this.email = email;
  }

  public String getAddress() {
      return address;
  }

  public void setAddress(String address) {
      this.address = address;
  }

  @Override
  public String toString() {
      return String.format("User [id=%s, firstName=%s, lastName=%s email=%s address=%s]", id, firstName, lastName, email, address);
  }

}

 

Post.java

package com.example.codingninjas;

import javax.persistence.*;

@Entity
public class Post {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private Integer id;

  private String content;

  @ManyToOne(targetEntity = User.class)
  @JoinColumn(name = "userId")
  private User user;

  protected Post() {
  }

  public Post(String content, User user) {
      this.content = content;
      this.user = user;
  }

  public Integer getId() {
      return id;
  }

  public void setId(Integer id) {
      this.id = id;
  }

  public String getContent() {
      return content;
  }

  public void setContent(String content) {
      this.content = content;
  }

  public User getUser() {
      return user;
  }

  public void setUser(User user) {
      this.user = user;
  }

  @Override
  public String toString() {
      return String.format("Post [id=%s, description=%s]", id);
  }


}

@ManyToOne annotation indicates that a user can do many posts. The relationship between post and user is many-to-one. 

@Entity annotation indicates that it is an entity and a table needs to be created for it.

Step 2: Connecting the services to use JPA

• Create UserRepository and PostRepository classes.

 

• Let UserRepository extend JpaRepository<User, Integer>.

 

• Let PostRepository extend JpaRepository<User, Integer>.
   

You will have to specify the entity that needs to be managed by JPARepository in <>.

 

UserRepository.java

package com.example.codingninjas;

import org.springframework.data.jpa.repository.JpaRepository;

public interface UserRepository extends JpaRepository<User, Integer> {

}

PostRepository.java
package com.example.codingninjas;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;

import java.util.List;

public interface PostRepository extends JpaRepository<Post, Integer> {

     @Query(value = "SELECT * FROM post WHERE user_id = :id", nativeQuery = true)
     List<Post> getAllPostsOfUser(Integer id);

}

@Query annotation is used to add dynamic queries in case we do  not find a suitable method provided by JPA to access the data from the table.

Step 3: Creating controllers to access the service

• Create a UserController.class and add the following endpoints
  
  
  • /addUser: to add a new user
  • /user/all: to get all the users
    
     
• Create a PostController.class and add the following endpoints.
  
   
• /addPost: to add the post
  
   
• /post/all: to get all the posts 
  
   
• /user/post/{id}: to get all the posts of a user.

 

UserController.class

package com.example.codingninjas;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;


import java.util.List;


@RestController
public class UserController {
   @Autowired
  private UserRepository userRepository;


  @PostMapping(path = "/addUser")
  public ResponseEntity<User> addNewUser(@RequestBody User user) {
      User savedUser = userRepository.save(user);
      return ResponseEntity.ok().body(savedUser);
  }


  @GetMapping(path = "/user/all")
  public ResponseEntity<List<User>> getAllUsers() {
      return  ResponseEntity.ok().body(userRepository.findAll());
  }


}

PostController.java

package com.example.codingninjas;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
public class PostController {
    @Autowired
   private PostRepository postRepository;

   @PostMapping(path = "/addPost")
   public ResponseEntity<Post> addNewUser(@RequestBody Post post) {

       Post savedPost = postRepository.save(post);
       return ResponseEntity.ok().body(savedPost);
   }

   @GetMapping(path = "/post/all")
   public ResponseEntity<List<Post>> getAllPosts() {
       return  ResponseEntity.ok().body(postRepository.findAll());
   }

   @GetMapping(path = "/user/post/{id}")
   public ResponseEntity<List<Post>> getAllPostsOfUserById(@PathVariable Integer id) {
       try{
           return ResponseEntity.ok().body(postRepository.getAllPostsOfUser(id));
       } catch (Exception e) {
           return ResponseEntity.badRequest().body(null);
       }
   }
}

Step 4: Running the service.

• Build and run the project

 

Open postman and add URL http://localhost:8080/addUser to add the user. Choose Post as HTTP method. Select body, then select raw and then select JSON from the dropdown. Add the following JSON and send the request. 
{
  "firstName": "ayeesha",
  "lastName": "rasha",
  "email": "ayeesharasha@gmail.com",
  "address": "temp address"
}

• You can add more users in the similar way. To see if the user is saved or not in the new tab add the URL http://localhost:8080/user/all and HTTP method as GET and send the request.

• The similar as we added the user we will be adding the post of the user with following JSON data, URL = http://localhost:8080/addPost, HTTP method: POST

The post is added to the table post.

Add some more post for some other users as well. After adding my POST table looks something like this.

• To see all the post of the particular user navigate to URL http://localhost:8080/user/post/5 where 5 is the id of the user and send a GET request.

Try it yourself -  test the endpoint /post/all and check if you get all the posts.

Frequently Asked Questions

What does Spring Boot's post method do?

The Spring Boot applications handle the post request performed by the client with the JSON data in the header area where the PostMapping () annotation is most frequently used. The project's Spring web is being initialized.

What is the POST API's operation?

To build or edit resources in web services, POST requests are used to submit data to the API server. In the request body of an HTTP request, the server stores the data that was delivered to it. A website's contact form serves as the most basic illustration.

What distinguishes the REST and SOAP APIs from one another?

REST is an architectural design approach, whereas SOAP is a protocol. A service interface is used by SOAP, whereas URIs are used by REST for an API, which is meant to expose certain portions of an application's business logic on a server.

I want to use the REST API, but how do I POST a request?

Sending an HTTP POST request to the REST API server and including JSON data in the body of the POST message are required steps in posting JSON to a REST API endpoint. Using the Content-Type: application/json request header, you must specify the data type in the body of the POST message.

Is it possible to update data using the POST method?

To update a resource, you can use POST, but not with the same URL as the resource you're changing.

In the REST, is it possible to use "Put" instead of "POST"?

POST would be applied to a list of questions if you wanted to utilize it. The PUT command would be used for a specific query if you wanted to utilize it.

Conclusion

This article demonstrates how to create a Post for a User by implementing the POST service by Spring Boot to produce a post for users in Spring

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