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/users@cxf.apache.org/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
