Restlet实战（四）与Spring集成

在上一篇文章中介绍了如何在restlet.xml中设置Component，本篇将介绍restlet如何和Spring结合。

 

首先将相应的jar文件放到WEB-INF/lib下，针对上一篇的示例代码，我们做一些修改，当然也包括一些配置。

 

首先

 

在web.xml注释掉如下代码：

 

<servlet>
   <servlet-name>RestletServlet</servlet-name>
   <servlet-class>
      com.noelios.restlet.ext.servlet.ServerServlet
   </servlet-class>
</servlet>


<servlet-mapping>
   <servlet-name>RestletServlet</servlet-name>
   <url-pattern>/*</url-pattern>
</servlet-mapping>

 

 因为有专门的SpringServlet来处理请求，所以，加入如下代码：

 <context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath*:applicationContext*.xml</param-value>
 </context-param>

 <listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
 </listener>

 <servlet>
<servlet-name>restlet</servlet-name>
<servlet-class>com.noelios.restlet.ext.spring.SpringServerServlet</servlet-class>
<init-param>
    <param-name>org.restlet.component</param-name>
    <param-value>component</param-value>
</init-param>
</servlet>

 <servlet-mapping>
<servlet-name>restlet</servlet-name>
<url-pattern>/resources/*</url-pattern>
 </servlet-mapping>

 

接下来对CustomerResource做一修改，值得注意的是与Spring集成，Resource类里面有一些规则，首先必须有一个无参的构造参数，一个init方法，这个方法包含那些原来定义在非默认构造函数的代码。

 

public class CustomerResource extends Resource {
    String customerId = "";
    private CustomerDAO customerDAO;

    @Override
    public void init(Context context, Request request, Response response) {
        super.init(context, request, response);
        customerId = (String) request.getAttributes().get("custId");
    }

    public CustomerResource(){
        getVariants().add(new Variant(MediaType.TEXT_PLAIN));
    }

    public CustomerResource(Context context, Request request, Response response) {
        super(context, request, response);

        getVariants().add(new Variant(MediaType.TEXT_PLAIN));
    }

    @Override
    public Representation getRepresentation(Variant variant) {
        String userMsg = customerDAO.getCustomerById(customerId);
        Representation representation = new StringRepresentation(userMsg,
                MediaType.TEXT_PLAIN);
        return representation;
    }

    public void setCustomerDAO(CustomerDAO customerDAO) {
        this.customerDAO = customerDAO;
    }
}

 需要说明的是按照现在三层架构流行分法，我们姑且认为Resource就是我们常说的Service层，那么在resource里面我们需要调用数据层的类来完成对数据的处理。上面代码中，我创建了一个CustomerDAO作为数据处理层，相关类代码如下：

public interface CustomerDAO {
    public String getCustomerById(String id);
}

 

public class CustomerDAOImpl implements CustomerDAO{
    public String getCustomerById(String id){
        //get other information through id such as name, no, address etc.
        String name = "ajax";
        String address=  "Shanghai";
        return "The customer name is " + name + " and he is from " + address;
    }
}

 

Spring配置文件applicationContext-***.xml：

<?xml version="1.0" encoding="UTF-8"?>

<beans  default-autowire="byName" xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

    <bean id="component" class="org.restlet.ext.spring.SpringComponent">
        <property name="defaultTarget" ref="restRoute" />
    </bean>
    <bean id="restRoute" class="org.restlet.ext.spring.SpringRouter">
        <property name="attachments">
            <map>
                <entry key="/customers/{custId}">
                    <bean class="org.restlet.ext.spring.SpringFinder">
                        <lookup-method name="createResource" bean="customerResource" />
                    </bean>
                </entry>
            </map>
        </property>
    </bean>

    <bean id="customerResource" class="com.mycompany.restlet.resource.CustomerResource" scope="prototype">
        <property name="customerDAO" ref="customerDAO" />
    </bean>

    <bean id="customerDAO" class="com.mycompany.restlet.dao.CustomerDAOImpl"/>
</beans>

 

ok,所有配置以及代码完成，下面做一个简单的测试，打开浏览器输入：http://localhost:8080/restlet/resources/customers/1

 

页面结果是：

The customer name is ajax and he is from Shanghai

 

 

看上面的Spring配置，如果有多个URL，例如

/customers/{custId},

/customers/{custId}/orders,

/customers/{custId}/orders/{orderId}

 

那么/customers需要重复三次，有什么办法简化吗？看下面改造后的配置：

<bean id="restRoute" class="org.restlet.ext.spring.SpringRouter">
    <property name="attachments">
        <map>
            <entry key="/customers" value-ref="customerRoute" />
        </map>
    </property>
</bean>

<bean id="customerRoute" class="org.restlet.ext.spring.SpringRouter">
    <property name="attachments">
        <map>
            <entry key="/{customerId}">
                <bean class="org.restlet.ext.spring.SpringFinder">
                    <lookup-method name="createResource" bean="customerResource" />
                </bean>
            </entry>
        </map>
    </property>
</bean>

 

这样，可以动态配置基于/customers/*的URL了，如果你仍旧不明白，看一下官方的restlet与Spring结合的例子。