[英]Autowired annotation in Servlet Spring
I have problem (when i'm calling method from another component class) with NullPointerException
like this: 我有这样的NullPointerException
问题(当我从另一个组件类调用方法时):
ERROR [UploadServlet] - Servlet.service() for servlet UploadServlet threw exception
java.lang.NullPointerException
at pl.crai.servlets.FileUploadServlet.doPost(FileUploadServlet.java:77)
at pl.crai.servlets.FileUploadServlet.handleRequest(FileUploadServlet.java:286)
at org.springframework.web.context.support.HttpRequestHandlerServlet.service(HttpRequestHandlerServlet.java:67)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
My spring version is 3.2 and it's my servlet class injection: 我的春季版本是3.2,这是我的servlet类注入:
@Component
public class FileUploadServlet implements HttpRequestHandler {
@Autowired
private MessagesPersistence messagesPersistence;
Next, my applicationContext.xml
: 接下来,我的applicationContext.xml
:
<bean name="UploadServlet" class="pl.crai.servlets.FileUploadServlet">
</bean>
spring-servlet.xml : spring-servlet.xml:
<mvc:annotation-driven />
<import resource="applicationContext.xml" />
<context:component-scan base-package="pl.crai" />
and entire web.xml
: 和整个web.xml
:
<display-name></display-name>
<listener>
<listener-class>
org.springframework.web.context.ContextLoaderListener
</listener-class>
</listener>
<filter>
<filter-name>CharacterEncodingFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
<init-param>
<param-name>forceEncoding</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CharacterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping >
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>spring</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>*.html</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>downloadAttachments</servlet-name>
<servlet-class>pl.crai.servlets.DownloadAttachmentsSerlvet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>downloadAttachments</servlet-name>
<url-pattern>/downFile/*</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>downloadMultipleAttachments</servlet-name>
<servlet-class>pl.crai.servlets.DownloadMultipleAttachmentsServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>downloadMultipleAttachments</servlet-name>
<url-pattern>/downMultipleFile/*</url-pattern>
</servlet-mapping>
<servlet>
<display-name>UploadServlet</display-name>
<servlet-name>UploadServlet</servlet-name>
<servlet-class>
org.springframework.web.context.support.HttpRequestHandlerServlet
</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UploadServlet</servlet-name>
<url-pattern>/uploadFile</url-pattern>
</servlet-mapping>
<filter>
<filter-name>LoginFilter</filter-name>
<filter-class>pl.crai.filters.LoginFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>LoginFilter</filter-name>
<url-pattern>*.html</url-pattern>
</filter-mapping>
</web-app>
I tried to try use different settings (without @Component
annatotion in servlet, with @Component("UploadServlet")
, without config in xml files, and more..) Please help! 我尝试尝试使用其他设置(在servlet中没有@Component
annatotion,在@xml中没有@Component
@Component("UploadServlet")
,在xml文件中没有配置,等等。)请帮助!
======================EDIT==================================== =====================编辑============================ =========
So.. when I removed <import resource= from spring-servlet.xml
autowired in another component in my project doesn't work. 所以..当我<import resource= from spring-servlet.xml
删除<import resource= from spring-servlet.xml
自动连接到项目中的另一个组件中的操作无效。
My uprgade version of web.xml is: 我的web.xml的升级版本是:
<display-name></display-name>
<listener>
<listener-class>
org.springframework.web.context.ContextLoaderListener
</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath*:applicationContext.xml</param-value>
</context-param>
<filter>
<filter-name>CharacterEncodingFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
<init-param>
<param-name>forceEncoding</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CharacterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping >
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>spring</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>*.html</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>downloadAttachments</servlet-name>
<servlet-class>pl.crai.servlets.DownloadAttachmentsSerlvet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>downloadAttachments</servlet-name>
<url-pattern>/downFile/*</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>downloadMultipleAttachments</servlet-name>
<servlet-class>pl.crai.servlets.DownloadMultipleAttachmentsServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>downloadMultipleAttachments</servlet-name>
<url-pattern>/downMultipleFile/*</url-pattern>
</servlet-mapping>
<servlet>
<display-name>UploadServlet</display-name>
<servlet-name>UploadServlet</servlet-name>
<servlet-class>
org.springframework.web.context.support.HttpRequestHandlerServlet
<!-- org.springframework.web.context.support.HttpRequestHandlerServlet -->
</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UploadServlet</servlet-name>
<url-pattern>/uploadFile</url-pattern>
</servlet-mapping>
<filter>
<filter-name>LoginFilter</filter-name>
<filter-class>pl.crai.filters.LoginFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>LoginFilter</filter-name>
<url-pattern>*.html</url-pattern>
</filter-mapping>
</web-app>
But it still doesn't work with another exception: 但是它仍然不能与另一个例外一起使用:
Allocate exception for servlet UploadServlet
org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'UploadServlet' is defined
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:549)
at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1096)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:278)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:198)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1121)
at org.springframework.web.context.support.HttpRequestHandlerServlet.init(HttpRequestHandlerServlet.java:57)
at javax.servlet.GenericServlet.init(GenericServlet.java:211)
Your UploadServlet
should be defined in your root web application context (the one loaded up by ContextLoaderListener
): 应该在根Web应用程序上下文(由ContextLoaderListener
加载的根上下文)中定义UploadServlet
:
So the changes should be, add the bean to your applicationContext.xml file, which you have already done. 因此更改应该是将Bean添加到您已经完成的applicationContext.xml文件中。 Remove <import resource..
from your servlet-context.xml
file Load up applicationContext.xml instead through ContextLoaderListener
, NOT through <import resource...
, so in your web.xml: 从servlet-context.xml
文件中删除<import resource..
而不是通过ContextLoaderListener
而不是通过<import resource...
,加载applicationContext.xml,因此在您的web.xml中:
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</context-param>
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