Apache CXF实现Web Service（4）——Tomcat容器和Spring实现JAX-RS(RESTful) web service

准备

我们仍然使用 Apache CXF实现Web Service（2）——不借助重量级Web容器和Spring实现一个纯的JAX-RS(RESTful) web service 中的代码作为基础，并引入spring来进行RESTful web service的配置和管理。

项目目录结构如下图

首先我们要在web.xml中加入通过Spring的ContextLoaderListener加载的Spring运行时环境以及CXF的Spring配置文件

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" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
   <display-name>cxf</display-name>  

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/cxf-servlet.xml</param-value>
    </context-param>  

    <!--设置一起动当前的Web应用，就加载Spring，让Spring管理Bean -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>  

  <servlet>
    <description>m CXF Endpoint</description>
    <display-name>cxf</display-name>
    <servlet-name>cxf</servlet-name>
    <servlet-class>org.apache.cxf.transport.servlet.CXFServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>cxf</servlet-name>
    <url-pattern>/services/*</url-pattern>
  </servlet-mapping>
  <session-config>
    <session-timeout>60</session-timeout>
  </session-config>
</web-app>

需要注意的是Spring配置文件的命名和路径"/WEB-INF/cxf-servlet.xml"，如果将项目文件重命名为applicationContext.xml，同时修改web.xml里面为"/WEB-INF/applicationContext.xml"，Tomcat服务器启动的时候会提示错误信息：（稍后我们来讲如何解决这个问题）

org.springframework.beans.factory.BeanDefinitionStoreException: IOException parsing XML document from ServletContext resource [/WEB-INF/cxf-servlet.xml]; nested exception is java.io.FileNotFoundException: Could not open ServletContext resource [/WEB-INF/cxf-servlet.xml]
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:341)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:302)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:174)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:209)
    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:180)
    at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:125)
    at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:94)
    at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:130)
    at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:537)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:451)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:389)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:294)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4793)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5236)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.io.FileNotFoundException: Could not open ServletContext resource [/WEB-INF/cxf-servlet.xml]
    at org.springframework.web.context.support.ServletContextResource.getInputStream(ServletContextResource.java:140)
    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:328)
    ... 21 more

在/WEB-INF目录下，我们加入文件cxf-servlet.xml

<?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:jaxrs="http://cxf.apache.org/jaxrs"
    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://cxf.apache.org/jaxrs
	    http://cxf.apache.org/schemas/jaxrs.xsd">
    <import resource="classpath:META-INF/cxf/cxf.xml"/>
    <import resource="classpath:META-INF/cxf/cxf-servlet.xml"/>  

    <bean id="roomService"
    	class="com.cnblog.richaaaard.cxftest.spring.rs.helloworld.service.RoomService">
    </bean>  

	<jaxrs:server id="restContainer" address="/">
        <jaxrs:serviceBeans>
            <ref bean="roomService" />
        </jaxrs:serviceBeans>
         <jaxrs:providers>
        	<bean class="org.codehaus.jackson.jaxrs.JacksonJaxbJsonProvider" />
    	</jaxrs:providers>
<!--         <jaxrs:extensionMappings> -->
<!--         <entry key="json" value="application/json" /> -->
<!--         <entry key="xml" value="application/xml" /> -->
<!--     </jaxrs:extensionMappings> -->
    </jaxrs:server>
</beans>

　　注意

文件中的Spring支持，还有http://cxf.apache.org/jaxrs http://cxf.apache.org/schemas/jaxrs.xsd（如果是ws类型的web service则需要引入jaxws的规范）

我们还可以看到，文件通过Spring bean的配置将roomService的实例注入到了jaxrs:server之中。

红色高亮的"import resource"部分也是必须的，否则在Tomcat服务器启动的时候会出错：

信息: Loading XML bean definitions from URL [file:/Users/Richard/Documents/Dev/workspace/eclipse/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps/cxf-test-rs-spring-helloworld/WEB-INF/cxf-servlet.xml]
十二月 02, 2015 4:34:02 下午 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@58318a06: defining beans [roomService,restContainer]; parent: org.springframework.beans.factory.support.DefaultListableBeanFactory@22252012
566 [localhost-startStop-1] INFO org.apache.cxf.endpoint.ServerImpl - Setting the server's publish address to be /
十二月 02, 2015 4:34:02 下午 org.springframework.beans.factory.support.DefaultSingletonBeanRegistry destroySingletons
信息: Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@58318a06: defining beans [roomService,restContainer]; parent: org.springframework.beans.factory.support.DefaultListableBeanFactory@22252012
十二月 02, 2015 4:34:02 下午 org.apache.catalina.core.ApplicationContext log
严重: StandardWrapper.Throwable
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'restContainer': Invocation of init method failed; nested exception is org.apache.cxf.service.factory.ServiceConstructionException
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1482)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:521)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:628)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
    at org.apache.cxf.transport.servlet.CXFServlet.createSpringContext(CXFServlet.java:151)
    at org.apache.cxf.transport.servlet.CXFServlet.loadBus(CXFServlet.java:74)
    at org.apache.cxf.transport.servlet.CXFNonSpringServlet.init(CXFNonSpringServlet.java:77)
    at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1231)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1144)
    at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1031)
    at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4978)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5270)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.cxf.service.factory.ServiceConstructionException
    at org.apache.cxf.jaxrs.JAXRSServerFactoryBean.create(JAXRSServerFactoryBean.java:219)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)

"import resource"起什么作用？

待研

最后

我们在Tomcat中运行Web项目，并通过浏览器访问

*扩展

• 为什么使用applicationContext.xml服务器会出错，从错误信息看，它仍然尝试去寻找cxf-servlet.xml文件？

　　　　在查看项目结构后发现在/WebContent/WEB-INF中还有一个web.xml里面指定的文件是cxf-servlet.xml，这个web.xml和我们在/src/main/webapp/WEB-INF下的文件不同步，Tomcat启动时读取的文件在WebContent下，修改后服务器就正常了。

　　　　

为什么会这样？那么又如何使src下的文件与WebContent中的文件保持同步呢？（其实这都是网上转来转去的例子惹得祸）

我们右键查看整个项目的属性Properties->Web Deployment Assembly 发现在部署配置下 /src/main/webapp 和 /WebContent 都输出到服务器部署目标的根目录下 "/" 且 "/WebContent" 在 "/src/main/webapp" 之后输出，所以会覆盖之前webapp下的内容，所以我们要做的是只要保留一个输出——删除webapp这行配置，然后将原来webapp下的applicationContext.xml文件拷贝到WebContent下。

经过试验，server可以正常启动。

• "import resource"起什么作用？为什么它的路径是"classpath:META-INF/cxf/cxf.xml"与"classpath:META-INF/cxf/cxf-servlet.xml"

我们发现cxf.xml和cxf-servlet.xml两个文件并不在我们项目源码的路径中，那么是不是在cxf相关的jar包中呢？

答案是肯定的

cxf.xml存在于cxf-core.jar中 /META-INF/cxf/cxf.xml

<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" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    <!--  For Testing using the Spring commons processor, uncomment one of:-->
    <!--
                <bean class="org.springframework.context.annotation.CommonAnnotationBeanPostProcessor"/>
                <context:annotation-config/>
        -->
    <bean id="cxf" class="org.apache.cxf.bus.spring.SpringBus" destroy-method="shutdown"/>
    <bean id="org.apache.cxf.bus.spring.BusWiringBeanFactoryPostProcessor" class="org.apache.cxf.bus.spring.BusWiringBeanFactoryPostProcessor"/>
    <bean id="org.apache.cxf.bus.spring.Jsr250BeanPostProcessor" class="org.apache.cxf.bus.spring.Jsr250BeanPostProcessor"/>
    <bean id="org.apache.cxf.bus.spring.BusExtensionPostProcessor" class="org.apache.cxf.bus.spring.BusExtensionPostProcessor"/>
</beans>

　　cxf-servlet.xml存在与cxf-rt-transports-http.jar中

<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:foo="http://cxf.apache.org/configuration/foo" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

</beans>

奇怪的是这里的cxf-servlet.xml里面什么都没有申明，那么我们是否可以将其去掉呢？（答案？？？自行验证）

所以之前在Spring中配置的cxf-servlet.xml只是与这里的import resource里面的恰好相同而已，两个文件不是同一个，路径也不一样。

那么cxf-core.jar里面的这个文件cxf.xml里面的配置有什么用呢？

后文分解：）

参考：

https://www.mail-archive.com/[e-mail]/msg00488.html

http://www.cnblogs.com/hoojo/archive/2011/03/30/1999563.html

http://www.kuqin.com/shuoit/20140716/341250.html

https://cwiki.apache.org/confluence/display/CXF20DOC/JAXRS+Services+Configuration