Ein Leitfaden für JavaLite - Erstellen einer RESTful CRUD-Anwendung

<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"
    }]----

.. eine von ihnen aktualisieren:

[source,bash,gutter:,true]

... lesen Sie den, den wir gerade aktualisiert haben:

[source,bash,gutter:,true]

Zum Schluss können wir einen löschen:

[source,bash,gutter:,true]

[[conclusions]]

===  **  9. Fazit**

JavaLite bietet eine Vielzahl von Tools, die Entwicklern helfen, eine Anwendung innerhalb von Minuten in Betrieb zu nehmen. Während die Konventionen zwar zu einem saubereren und einfacheren Code führen, dauert es jedoch eine Weile, bis die Benennung und der Speicherort von Klassen, Paketen und Dateien bekannt sind.

Dies war nur eine Einführung in ActiveWeb und ActiveJDBC. Weitere Informationen finden Sie auf ihrer http://javalite.io[Website]. Suchen Sie nach unserer Produktanwendung unter https://github.com/eugenp/tutorials/tree/master/java- lite[das Github-Projekt].