Virgo与Maven整合开发环境搭建(四)

               4.web

                     接下来是这次demo的另一个bundle.而且是个拥有spring-mvc能力的web-bundle(WAB).先来看一下结构

                       首先来看一下web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app
		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		xmlns="http://java.sun.com/xml/ns/javaee"
		xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
		xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
		version="2.5">

	<display-name>Search Web Module</display-name>

	<servlet>
		<servlet-name>search</servlet-name>
    	<servlet-class>org.phantom.web.virgo.servlet.DispatcherServlet</servlet-class>
    	<init-param>
    		<param-name>contextClass</param-name>
    		<param-value>org.eclipse.virgo.web.dm.ServerOsgiBundleXmlWebApplicationContext</param-value>
    	</init-param>
	</servlet>

	<servlet-mapping>
		<servlet-name>search</servlet-name>
		<url-pattern>/*</url-pattern>
	</servlet-mapping>
</web-app>

                      在这个demo中,我们使用的是Spring-MVC,所以,这里加入Spring-MVC支持.这里用到了一个自定义扩展类org.phantom.web.virgo.servlet.DispatcherServlet。说明一下这个类的作用。在OSGI中，每个bundle都是独立的，它拥有独立的ClassLoad，独立的Spring ApplicationContext.但是我们要通过spring从一个bundle中获取另一个bundle的服务,即我们需要这些applicationContext互相认识.怎么做到呢?virgo对这事做了支持.它提供了一个类org.eclipse.virgo.web.dm.ServerOsgiBundleXmlWebApplicationContext.这个类就相当于一个OSGI全局的applicationContext.我们这里就是要将这个类注入到Spring-MVC的DispatcherServlet中.这里通过扩展默认的DispatcherServlet来达到目的

public class DispatcherServlet extends org.springframework.web.servlet.DispatcherServlet{
	@Override
	public void init(ServletConfig config) throws ServletException {
		String contextClass = config.getInitParameter("contextClass");
		if (contextClass != null) {
			try {
				setContextClass(Class.forName(contextClass));
			} catch (ClassNotFoundException e) {
				throw new ServletException(String.format("Context class %s not found", contextClass), e);
			}
		}
		super.init(config);
	}
}

                    然后来看一下OSGI描述.

Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: search web module
Bundle-SymbolicName: org.phantom.demo.web
Bundle-Version: 1.0.0.SNAPSHOT
Import-Template: org.springframework.*;version="[3.0.5,4)"
Import-Package: org.springframework.context.config;version="[3.0.5,4)",
 org.springframework.web.servlet.config;version="[3.0.5,4)"
Excluded-Imports: org.phantom.demo.web
Snap-Host: org.phantom.demo.host;version="1.0.0.SNAPSHOT"
Snap-ContextPath: /search

                    这里要介绍Snap-ContextPath:/search.前文已经介绍过Host-Snap,这一句配置就是配置当前bundle的请求路径,即第二级路径.还有一句Snap-Host:org.org.phantom.demo.host.这句配置将当前snap挂载到了某个host上.于是,根据前文的介绍,当进入到/demo后,SnapHostFilter开始工作,拿到请求的第二级/search,分发到当前bundle.     

                    接下来的配置就是Spring-MVC的配置了.在WEB-INF/创建与DispatcherServlet同名的search-servlet.xml即可

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xmlns:util="http://www.springframework.org/schema/utils"
	xmlns:osgi="http://www.springframework.org/schema/osgi"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd
		http://www.springframework.org/schema/osgi http://www.springframework.org/schema/osgi/spring-osgi-1.2.xsd">

	<context:component-scan base-package="org.phantom.demo.web" />
	<mvc:annotation-driven/>
	
	<mvc:resources location="/" mapping="*.html"/>
	<mvc:resources location="/resources/" mapping="/resources/**" />

	<osgi:reference id="pictureSearch" interface="org.phantom.demo.api.SearchHandler" bean-name="pictureSearch"/>
 </beans> 
 

                     一句句解释一下.第一句,打开包扫描,将Controller加入到Spring管理中

<context:component-scan base-package="org.phantom.demo.web" />

                     接下来打开mvc的支持.将一些Spring-MVC默认的View、Convertor加入进来。

<mvc:annotation-driven/>

                     后面两句,是对一些静态资源放行的配置,因为我们servlet的拦截模式是/*,所以,静态资源直接放行

	<mvc:resources location="/" mapping="*.html"/>
	<mvc:resources location="/resources/" mapping="/resources/**" />

                      这句就是通过Spring-DM获取一个OSGI服务的配置.这里我们只获取图片搜索的实现,MP3的我们留在后续章节,用来说明OSGI的动态性如何体现.

<osgi:reference id="pictureSearch" interface="org.phantom.demo.api.SearchHandler" bean-name="pictureSearch"/>

                       同样,我们与普通OSGI进行一下对比.在普通OSGI中,想要或者一个服务如何编写

		try {
			SearchHandler handler = null;
			ServiceReference<SearchHandler>[] srs = (ServiceReference<SearchHandler>[]) bundleContext.getServiceReferences(SearchHandler.class.getName(),"(bean-name='picutreSearch')");
			if(srs!=null && srs.length>0)
				handler = bundleContext.getService(srs[0]);
			
		} catch (InvalidSyntaxException e) {
			e.printStackTrace();
		}

                     最后来看一下Controller如何编写

package org.phantom.demo.web;

import java.util.List;

import javax.annotation.Resource;

import org.phantom.demo.api.SearchBean;
import org.phantom.demo.api.SearchHandler;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
@RequestMapping("/_s")
public class SearchController {

	@Resource
	private SearchHandler handler = null;

	@RequestMapping(method = RequestMethod.GET)
	public ResponseEntity<List<? extends SearchBean>> doSearch(String key) {
		List<? extends SearchBean> list = handler.doSearch(key);
		return new ResponseEntity<List<? extends SearchBean>>(list, HttpStatus.OK);
	}
}

                     在Controller中,将获取到的服务注入进来.

       @Resource
	private SearchHandler handler = null;

                      ok,然后编写一个很简单的页面.点击按钮发送请求页面上发送一个get请求到Controller,Controller调用service完成整个流程.

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script type="text/javascript" src="../resources/jquery-1.6.min.js"></script>
<script type="text/javascript">
$(function(){
$(":button").click(function(){
	$.ajax({
		url:'_s',
		type:'get',
		data:{key:$(":text").val()},
		success:function(result){
			alert(result);
		}
	});
});
});
</script>
</head>
<body>
<input/><input type="button" value="search"/>
</body>
</html>

                     所有bundle开发完后,按照依赖关系,依次执行mvn install安装到本地maven仓库.之前已经配置了maven仓库与virgo关联.所以这种开发流程基本是：开发完—install—启动virgo.

                     然后到${virgo_home}/pickup/新建一个plan,即一次部署计划.

<?xml version="1.0" encoding="UTF-8"?>
<plan name="com.faben.demo.plan" version="1.0.0.SNAPSHOT" scoped="false" atomic="false"
        xmlns="http://www.eclipse.org/virgo/schema/plan"
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xsi:schemaLocation="
                        http://www.eclipse.org/virgo/schema/plan 
                        http://www.eclipse.org/virgo/schema/plan/eclipse-virgo-plan.xsd">

        <artifact type="bundle" name="org.phantom.demo.host" version="1.0.0.SNAPSHOT"/>
        <artifact type="bundle" name="org.phantom.demo.web" version="1.0.0.SNAPSHOT"/>
        <artifact type="bundle" name="org.phantom.demo.search.picture" version="1.0.0.SNAPSHOT"/>
</plan>

                      部署计划中只需要写实现包和web包,被依赖的包比如api不用写,Virgo会根据MANIFEST.MF中的依赖定义,在maven库中找到api并加载.

                     做完这些后,启动virgo,访问http://localhost:8080/demo/search/index.html.

                  点击按钮,通过firebug查看请求和返回的数据