JavaLiteガイド - RESTful CRUDアプリケーションの構築

<dependency>
    <groupId>org.javalite</groupId>
    <artifactId>activeweb</artifactId>
    <version>1.15</version>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.45</version>
</dependency>

<plugin>
    <groupId>org.javalite</groupId>
    <artifactId>activejdbc-instrumentation</artifactId>
    <version>1.4.13</version>
    <executions>
        <execution>
            <phase>process-classes</phase>
            <goals>
                <goal>instrument</goal>
            </goals>
        </execution>
    </executions>
</plugin>

@RESTful
public class ProductsController extends AppController {

    public void index() {
       //...
    }

}

http://<host>:<port>/products

@RESTful
public class ProductsController extends AppController {

    public void index() {
       //code to get all products
    }

    public void create() {
       //code to create a new product
    }

    public void update() {
       //code to update an existing product
    }

    public void show() {
       //code to find one product
    }

    public void destroy() {
       //code to remove an existing product
    }
}

src
 |----main
       |----java.app
       |     |----config
       |     |----controllers
       |     |----models
       |----resources
       |----webapp
             |----WEB-INF
             |----views

public class DbConfig extends AbstractDBConfig {
    @Override
    public void init(AppContext appContext) {
        this.configFile("/database.properties");
    }
}

development.driver=com.mysql.jdbc.Driver
development.username=user
development.password=password
development.url=jdbc:mysql://localhost/dbname

public class AppControllerConfig extends AbstractControllerConfig {

    @Override
    public void init(AppContext appContext) {
        add(new DBConnectionFilter()).to(ProductsController.class);
    }
}

public class AppBootstrap extends Bootstrap {
    public void init(AppContext context) {}
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns=...>

    <filter>
        <filter-name>dispatcher</filter-name>
        <filter-class>org.javalite.activeweb.RequestDispatcher</filter-class>
        <init-param>
            <param-name>exclusions</param-name>
            <param-value>css,images,js,ico</param-value>
        </init-param>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
    </filter>

    <filter-mapping>
        <filter-name>dispatcher</filter-name>
        <url-pattern>/** </url-pattern>
    </filter-mapping>

</web-app>

@RESTful
public class ProductsController extends AppController {

    private ObjectMapper mapper = new ObjectMapper();

    public void index() {
        List<Product> products = Product.findAll();
       //...
    }

    public void create() {
        Map payload = mapper.readValue(getRequestString(), Map.class);
        Product p = new Product();
        p.fromMap(payload);
        p.saveIt();
       //...
    }

    public void update() {
        Map payload = mapper.readValue(getRequestString(), Map.class);
        String id = getId();
        Product p = Product.findById(id);
        p.fromMap(payload);
        p.saveIt();
       //...
    }

    public void show() {
        String id = getId();
        Product p = Product.findById(id);
       //...
    }

    public void destroy() {
        String id = getId();
        Product p = Product.findById(id);
        p.delete();
       //...
    }
}

{
    "id" : ${product.id},
    "name" : "${product.name}"
}

----[<@render partial="product" collection=products/>]----

@RESTful
public class ProductsController extends AppController {

    public void index() {
        List<Product> products = Product.findAll();
        view("products", products);
        render();
    }

    public void show() {
        String id = getId();
        Product p = Product.findById(id);
        view("product", p);
        render("__product");
    }
}

{
    "message" : "${message}",
    "code" : ${code}
}

view("message", "There was an error.", "code", 200);
render("message");

@RESTful
public class ProductsController extends AppController {

    private ObjectMapper mapper = new ObjectMapper();

    public void index() {
        view("products", Product.findAll());
        render().contentType("application/json");
    }

    public void create() {
        Map payload = mapper.readValue(getRequestString(), Map.class);
        Product p = new Product();
        p.fromMap(payload);
        p.saveIt();
        view("message", "Successfully saved product id " + p.get("id"), "code", 200);
        render("message");
    }

    public void update() {
        Map payload = mapper.readValue(getRequestString(), Map.class);
        String id = getId();
        Product p = Product.findById(id);
        if (p == null) {
            view("message", "Product id " + id + " not found.", "code", 200);
            render("message");
            return;
        }
        p.fromMap(payload);
        p.saveIt();
        view("message", "Successfully updated product id " + id, "code", 200);
        render("message");
    }

    public void show() {
        String id = getId();
        Product p = Product.findById(id);
        if (p == null) {
            view("message", "Product id " + id + " not found.", "code", 200);
            render("message");
            return;
        }
        view("product", p);
        render("__product");
    }

    public void destroy() {
        String id = getId();
        Product p = Product.findById(id);
        if (p == null) {
            view("message", "Product id " + id + " not found.", "code", 200);
            render("message");
            return;
        }
        p.delete();
        view("message", "Successfully deleted product id " + id, "code", 200);
        render("message");
    }

    @Override
    protected String getContentType() {
        return "application/json";
    }

    @Override
    protected String getLayout() {
        return null;
    }
}

<plugin>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-maven-plugin</artifactId>
    <version>9.4.8.v20171121</version>
</plugin>

mvn jetty:run

$ curl -X POST http://localhost:8080/products
  -H 'content-type: application/json'
  -d '{"name":"Water"}'
{
    "message" : "Successfully saved product id 1",
    "code" : 200
}

$ curl -X POST http://localhost:8080/products
  -H 'content-type: application/json'
  -d '{"name":"Bread"}'
{
    "message" : "Successfully saved product id 2",
    "code" : 200
}

$ curl -X GET http://localhost:8080/products[    {
        "id" : 1,
        "name" : "Water"
    },
    {
        "id" : 2,
        "name" : "Bread"
    }]----

それらのうちの1つを更新します。

[source,bash,gutter:,true]

...先ほど更新したものを読んでください。

[source,bash,gutter:,true]

最後に、削除することができます。

[source,bash,gutter:,true]

[[conclusions]]

===  **  9結論**

JavaLiteには、開発者がアプリケーションを短時間で起動して実行できるようにするためのツールが多数あります。ただし、規則に基づいてコードを作成するとコードがよりクリーンで単純になりますが、クラス、パッケージ、およびファイルの名前と場所を理解するにはしばらく時間がかかります。

これはActiveWebとActiveJDBCの紹介にすぎません。詳細はhttp://javalite.io[Webサイト]にあり、https://github.com/eugenp/tutorials/tree/master/java-で当社の製品アプリケーションを探してください。 lite[Githubプロジェクト]。