Hello together,

as you may know, I am writing a game "Hammurabi", which shall be connected to Hive someday.

This post bases on Implementation of Swagger.io und Postman to Springboot.

Here I want to show what I did, to enhance the functionality of the Webserver. Until now it only supports get requests (read).
I also want to be able to Create, (Read), Update and Delete (CRUD) my data-set.

Create

To enable create, in the controller we need to refer to the repository-Interface. For this we create the new propertiy "userlogrepository" from the type UserlogRepository and make it public to Spring by marking it with "@Autowired":

@Autowired
UserlogRepository userlogrepository;

The second thing we need to do is to add the @Postmapping method, which creates a new userlog-Entry:

//Create -----------------------------------------------------------------
@PostMapping(value = "/userlogs")
public UserlogEntity newUserlog (@RequestBody UserlogEntity newUserlog)
{
    return userlogrepository.save(newUserlog);
}

Here is the complete UserlogController file (so far):

package org.chary.controller;

import org.chary.dto.Userlogdto;
import org.chary.entity.UserlogEntity;
import org.chary.repository.UserlogRepository;
import org.chary.services.UserlogService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.*;

import java.awt.*;
import java.util.ArrayList;
import java.util.List;

@RestController
@CrossOrigin("*")
@RequestMapping("/userlogcontroller")
public class UserlogController {

    @Autowired
    UserlogService userlogservice;  // Giving the interface to Spring.
    // Spring searches for a corresponding class and finds UserlogserviceImpl
    // Spring creates an instance of it and puts it into userlogservice

    @Autowired
    UserlogRepository userlogrepository;

    //Read -----------------------------------------------------------------
    @GetMapping(value = "/userlogs")  //curl -X -get http://localhost:8099/userlogcontroller/userlogs"
    public List<Userlogdto> getAllUserlogs() {
        System.out.println("Hier sind alle Userlog-Einträge: " + userlogservice.getAllUserlogs().toString());
        return userlogservice.getAllUserlogs();

    }

    @GetMapping(value = "/welcome")
    public String welcome() {
        return "Welcome to the Hamurabi-Game - Written by Achim Mertens";
    }

    //Create -----------------------------------------------------------------
    @PostMapping(value = "/userlogs")
    public UserlogEntity newUserlog (@RequestBody UserlogEntity newUserlog)
    {
        return userlogrepository.save(newUserlog);
    }
}

Now we can send data via curl:

C:\Users\User>curl -v -X POST http://localhost:8099/userlogcontroller/userlogs -H "Content-Type:application/json" -d "{\"id\":\"6\",\"username\":\"AxelSchweiss\",\"logintime\":\"2022-02-02 12:16\"}"

Or we can do it via Postman:

Read single value

Now I want to add the possibility to get only one data set.
I have added the following part into the controller:

        // Read Single Item
    @GetMapping(value = "/userlog/{id}")
        public Optional<UserlogEntity> one (@PathVariable String id)
        {
            return userlogrepository.findById(id);
        }

(I also changed the Type of the id from Integer to String.
(Which caused the error: Unknown integral data type for ids : java.lang.String. I had to comment out @GeneratedValue in the UserlogEntity class:
@Id
//@GeneratedValue is only allowed if ID is from type integer
))

To read the first dataset insert into the command line:

curl -v -X GET http://localhost:8099/userlogcontroller/userlog/1 -H "Content-Type:application/json"

Update

To get the feature, that the data can be updated, we add the following into UserController class:

    //Update ----------------------------------------------------------------
    //The object "userlogEntity" is automatecally created by Spring, so we don't need an instantiation here anywhere
    //The result of "userlogEntity" is copied into "userlogEntity"
    @PutMapping("/userlogs/{id}")
    public UserlogEntity replaceUserlog(@RequestBody UserlogEntity replaceUserlog, @PathVariable String id) {
        return userlogrepository.findById(id).map(userlogEntity -> {
                    userlogEntity.setUsername(replaceUserlog.getUsername());
                    userlogEntity.setLogintime(replaceUserlog.getLogintime());
                    return userlogrepository.save(userlogEntity);     })
                .orElseGet( () -> {
                    replaceUserlog.setId(id);
                    return userlogrepository.save(replaceUserlog);
                });
    }

After restarting the server, we are able to update some data, here the logindate of the dataset from ID=4:

And here we change a complete dataset (with ID=2) via postman:

Delete

We add the following to the controllerclass:

    /**
     * //Delete --------------------------------------------------------------------
     * curl -v -X GET http://localhost:8099/userlogcontroller/userlog/17 -H "Content-Type:application/json"
     **/
    @DeleteMapping("userlog/{id}")
    void delteUserlog(@PathVariable String id) {
        if (userlogrepository.findById(id).isPresent()) {
            userlogrepository.deleteById(id);
        }
    }

After rebooting we can delete a user:

Same with Postman:

At the end, our userlogcontroller looks like this:

package org.chary.controller;

import org.chary.dto.Userlogdto;
import org.chary.entity.UserlogEntity;
import org.chary.repository.UserlogRepository;
import org.chary.services.UserlogService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;
import java.util.Optional;

@RestController
@CrossOrigin("*")
@RequestMapping("/userlogcontroller")
public class UserlogController {

    @Autowired
    UserlogService userlogservice;  // Giving the interface to Spring.
    // Spring searches for a corresponding class and finds UserlogserviceImpl
    // Spring creates an instance of it and puts it into userlogservice

    @Autowired
    UserlogRepository userlogrepository;

    /**
     * //Read -----------------------------------------------------------------
     * //curl -X -get http://localhost:8099/userlogcontroller/userlogs"
     **/
    @GetMapping(value = "/userlogs")
    public List<Userlogdto> getAllUserlogs() {
        System.out.println("Hier sind alle Userlog-Einträge: " + userlogservice.getAllUserlogs().toString());
        return userlogservice.getAllUserlogs();
    }

    /**
     * // Read Single Item
     * curl -v -X GET http://localhost:8099/userlogcontroller/userlog/17 -H "Content-Type:application/json"
     **/
    @GetMapping(value = "/userlog/{id}")
    public Optional<UserlogEntity> one(@PathVariable String id) {
        return userlogrepository.findById(id);
    }


    @GetMapping(value = "/welcome")
    public String welcome() {
        return "Welcome to the Hamurabi-Game - Written by Achim Mertens";
    }

    /**
     * //Create -----------------------------------------------------------------
     * // curl -v -X POST http://localhost:8099/userlogcontroller/userlogs -H "Content-Type:application/json" -d "{\"id\":\"17\",\"username\":\"DickTat\",\"logintime\":\"2022-02-04 12:16\"}"
     */
    @PostMapping(value = "/userlogs")
    public UserlogEntity newUserlog(@RequestBody UserlogEntity newUserlog) {
        return userlogrepository.save(newUserlog);
    }

    /**
     * //Update ----------------------------------------------------------------
     * The object "userlogEntity" is automatecally created by Spring, so we don't need an instantiation here anywhere
     * The result of "userlogEntity" is copied into "userlogEntity"
     * Example:
     * curl --location --request PUT 'localhost:8099/userlogcontroller/userlogs/2' \
     * --header 'Content-Type: application/json' \
     * --data-raw '  {"id": "2","username": "AtzeTon","logintime": "2022-01-31 14:16:00"}'
     */
    @PutMapping("/userlogs/{id}")
    public UserlogEntity replaceUserlog(@RequestBody UserlogEntity replaceUserlog, @PathVariable String id) {
        return userlogrepository.findById(id).map(userlogEntity -> {
                    userlogEntity.setUsername(replaceUserlog.getUsername());
                    userlogEntity.setLogintime(replaceUserlog.getLogintime());
                    return userlogrepository.save(userlogEntity);
                })
                .orElseGet(() -> {
                    replaceUserlog.setId(id);
                    return userlogrepository.save(replaceUserlog);
                });
    }

    /**
     * //Delete --------------------------------------------------------------------
     * curl -v -X GET http://localhost:8099/userlogcontroller/userlog/17 -H "Content-Type:application/json"
     **/
    @DeleteMapping("userlog/{id}")
    void delteUserlog(@PathVariable String id) {
        if (userlogrepository.findById(id).isPresent()) {
            userlogrepository.deleteById(id);
        }
    }

}

So with this, we have a server, which

is connected to a H2 database,
has a swagger interface
can (C)reate data via http
can (R)ead the data via http
can (U)pdate data via http
can (D)elete data via http

One can see all features via the swagger-ui:

My Code is public available at github: https://github.com/achimmertens/Hamurabi

The next step is, that the server learns to read data from other API-REST servers. So stay tuned.

Regards, Achim

How To Set Up CRUD Methods In The Webserver

Create

Read single value

Update

Delete