Use Spring Boot to build RESTful API

1. Create a Spring Initializer project Idea

Add Web and create a project in Lombok dialog box, or after the establishment of the project pom.xmlto add dependencies:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

2. Use annotations to build RESTful API

Here there is no database with ArrayList as the operation target.

Create an entity class, as the object API operations

package top.cloudli.demo.model;

import lombok.AllArgsConstructor;
import lombok.Data;

@Data
@AllArgsConstructor
public class Character {
    private int id;
    private String name;
    private String racial;
    private String[] ability;
}

Lombok used herein, eliminating the need to write Getter, Setter and constructors, add the appropriate annotation will be automatically generated after lombok.

Creating Controller, implement RESTful API

@RestControllerEquivalent @Controllerand @ResponseBodya combination of the use of the annotation, MIME default application/json.

@GetMappingEquivalent @RequestMapping(method = {RequestMethod.GET}), similar to other comments.

package top.cloudli.demo.controller;

import org.springframework.web.bind.annotation.*;
import top.cloudli.demo.model.Character;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * CRUD for Character
 */
@RestController
@RequestMapping(path = "/character")
public class CharacterController {

    private ArrayList<Character> characters = (ArrayList<Character>) Stream.of(
            new Character(1, "罗小黑", "妖精", new String[]{"空间系-传送", "空间系-领域"}),
            new Character(2, "罗小白", "人类", null)
    ).collect(Collectors.toList());

    /**
     * 获取所有 Character
     * @return All Characters
     */
    @GetMapping()
    public List<Character> getCharacters() {
        return characters;
    }

    /**
     * 根据 id 获取 Character
     * @param id Id of Character
     * @return Character
     */
    @GetMapping(path = "{id}")
    public Character getCharacter(@PathVariable int id) {
        return characters.stream()
                .filter(character -> character.getId() == id)
                .findAny()
                .orElse(null);
    }

    /**
     * 更新 Character
     * @param character Changed Character
     * @return Updated Character
     */
    @PutMapping()
    public Character alterCharacter(@RequestBody Character character) {
        AtomicBoolean found = new AtomicBoolean(false);

        characters.replaceAll(c -> {
            if (c.getId() == character.getId()) {
                found.set(true);
                return character;
            } else return c;
        });

        return found.get() ? character : null;
    }

    /**
     * 添加 Character
     * @param character New Character
     * @return Inserted Character
     */
    @PostMapping()
    public Character addCharacter(@RequestBody Character character) {
        return characters.add(character) ? character : null;
    }

    /**
     * 删除 Character
     * @param id Id of Character
     * @return Id of Character deleted
     */
    @DeleteMapping(path = "{id}")
    public int deleteCharacter(@PathVariable int id) {
        return characters.removeIf(character -> character.getId() == id) ? id : -1;
    }
}

3. Run the project, access to the API

URL	method	operating
/character	GET	Get all of Character
/character/id	GET	Gets Character specified id
/character	PUT	Complete modified object Character, modify transfer
/character/id	DELETE	Delete the specified id Character

If ?id=xxxmanner, the annotation may be pathparameters removed.

Sending GETa request to http://localhost:8080/character:

[
    {
        "id": 1,
        "name": "罗小黑",
        "racial": "妖精",
        "ability": [
            "空间系-传送",
            "空间系-领域"
        ]
    },
    {
        "id": 2,
        "name": "罗小白",
        "racial": "人类",
        "ability": null
    }
]

Sending GETa request to http://localhost:8080/character/1:

{
    "id": 1,
    "name": "罗小黑",
    "racial": "妖精",
    "ability": [
        "空间系-传送",
        "空间系-领域"
    ]
}

DELETEWith the above request GET, as specified id after the success of Character will be deleted, delete the return of id.

Sending PUTa request to ` http://localhost:8080/characteradded to the Header Content-Type:application/json, Body portion of the modified data is complete:

{
    "id": 1,
    "name": "小黑",
    "racial": "妖精",
    "ability": [
        "空间系-传送"
    ]
}

After a successful return as above JSON data.

POSTPrevious request PUTas submitted after a successful return data.