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。

 

评论

4 楼 zhaoshunxin 2014-03-04  

你好， 对于customerResource 这个地方 是否可以配置多个@Get方法？

3 楼 gaofeng_867 2013-01-12  

按照你的步骤遇到问题了：
Error creating bean with name 'component' defined in URL [file:/F:/Tomcat6.0/webapps/RestletSpring/WEB-INF/classes/applicationContext.xml]:

2 楼 cocca883 2012-11-19  

这些博客写的太好了      感谢  在国内难得啊。

1 楼 xxooyy 2011-11-14  

applicationContext.xml配置不成功,导致customerDAO 映射不上,String userMsg = customerDAO.getCustomerById(customerId);    抛出NullPointerException 异常,搞不定啊,楼主帮忙啊