web.xml configuration information in spring mvc

The loading order in the web.xml file is : context-param -> listener -> filter -> servlet

 

<web-app>    

<display-name></display-name> defines the name of the WEB application    

<description></description> declares the description information of the WEB application       

<context-param></context-param> The context-param element declares application-wide initialization parameters.    

The <filter></filter> filter element associates a name with a class that implements the javax.servlet.Filter interface.    

<filter-mapping></filter-mapping> Once a filter is named, it is associated with one or more servlets or JSP pages using the filter-mapping element.    

Version 2.3 of the <listener></listener>servlet API added support for event listeners, which are notified when a session or servlet context is created, modified, and deleted. The Listener element indicates the event listener class.    

<servlet></servlet> When specifying initialization parameters or custom URLs to a servlet or JSP page, you must first name the servlet or JSP page. The Servlet element is used to accomplish this task.    

<servlet-mapping></servlet-mapping> The server generally provides a default URL for the servlet: http://host/webAppPrefix/servlet/ServletName. However, this URL is often changed so that the servlet can access initialization parameters or handle relative URLs more easily. When changing the default URL, use the servlet-mapping element.       

<session-config></session-config> If a session is not accessed for a certain period of time, the server can discard it to save memory. The timeout value for a single session object can be set explicitly by using the setMaxInactiveInterval method of HttpSession, or a default timeout value can be specified using the session-config element.       

<mime-mapping></mime-mapping> If a web application has specific files it wants to be guaranteed to be assigned a specific MIME type, the mime-mapping element provides this guarantee.    

<welcome-file-list></welcome-file-list> Instructs the server which file to use when it receives a URL that refers to a directory name instead of a file name.    

<error-page></error-page> can specify the page that will be displayed when a specific HTTP status code is returned, or when a specific type of exception is thrown.    

<taglib></taglib> Specifies an alias for the Tag Libraryu Descriptor file. This feature enables you to change the location of TLD files without editing the JSP pages that use these files.    

<resource-env-ref></resource-env-ref> declares a managed object associated with the resource.    

<resource-ref></resource-ref> declares an external resource used by a resource factory.    

<security-constraint></security-constraint> specifies the URLs that should be protected. It is used in conjunction with the login-config element    

<login-config></login-config> Specifies how the server should authorize users trying to access protected pages. It is used in conjunction with the security-constraint element.    

<security-role></security-role> gives a list of security roles that will appear in the role-name subelement of the security-role-ref element within the servlet element. Declaring roles separately makes it easier for advanced IDEs to handle security information.    

<env-entry></env-entry> declares the environment entry for the web application.    

<ejb-ref></ejb-ref> declares a reference to the EJB's home directory.    

<ejb-local-ref></ejb-local-ref> declares the application of an EJB's local home directory.   

</web-app>

 

 Web Application Icons: Indicates the large and small icons that IDEs and GUI tools use to represent web applications

<icon>   
<small-icon>/images/app_small.gif</small-icon>   
<large-icon>/images/app_large.gif</large-icon>   
</icon>

 

 Filter configuration: Associate a name with a class that implements the javaxs.servlet.Filter interface.

  <filter>   
        <filter-name>setCharacterEncoding</filter-name>   
        <filter-class>com.myTest.setCharacterEncodingFilter</filter-class>   
        <init-param>   
            <param-name>encoding</param-name>   
            <param-value>GB2312</param-value>   
        </init-param>   
  </filter>   
  <filter-mapping>   
        <filter-name>setCharacterEncoding</filter-name>   
        <url-pattern>/*</url-pattern>   
  </filter-mapping>   
6. Listener configuration   
  <listener>   
      <listerner-class>listener.SessionListener</listener-class>   
  </listener>   
7. Servlet configuration   
   basic configuration   
   <servlet>   
      <servlet-name>snoop</servlet-name>   
      <servlet-class>SnoopServlet</servlet-class>   
   </servlet>   
   <servlet-mapping>   
      <servlet-name>snoop</servlet-name>   
      <url-pattern>/snoop</url-pattern>   
   </servlet-mapping>   
   Advanced configuration   
   <servlet>   
      <servlet-name>snoop</servlet-name>   
      <servlet-class>SnoopServlet</servlet-class>   
      <init-param>   
         <param-name>foo</param-name>   
         <param-value>bar</param-value>   
      </init-param>   
      <run-as>   
         <description>Security role for anonymous access</description>   
         <role-name>tomcat</role-name>   
      </run-as>   
   </servlet>   
   <servlet-mapping>   
      <servlet-name>snoop</servlet-name>   
      <url-pattern>/snoop</url-pattern>   
   </servlet-mapping>   
   Element Description   
    <servlet></servlet> is used to declare the data of a servlet, which mainly has the following sub-elements:   
    <servlet-name></servlet-name> specifies the name of the servlet   
    <servlet-class></servlet-class> specifies the class name of the servlet   
    <jsp-file></jsp-file> specifies the full path of a JSP page in the web site   
    <init-param></init-param> is used to define parameters, there can be multiple init-params. Access initialization parameters in the servlet class through the getInitParamenter(String name) method   
    <load-on-startup></load-on-startup> specifies the order in which servlets are loaded when the web application starts.   
    When the value is positive or zero: the servlet container loads the servlets with smaller values ​​first, and then loads other servlets with larger values ​​in turn.   
   When the value is negative or undefined: the servlet container will load this servlet the first time a web client accesses it   
    <servlet-mapping></servlet-mapping> is used to define the URL corresponding to the servlet and contains two sub-elements   
    <servlet-name></servlet-name> specifies the name of the servlet   
    <url-pattern></url-pattern> specifies the URL corresponding to the servlet

 

Session timeout configuration (in minutes)

<session-config>   
    <session-timeout>120</session-timeout>   
</session-config>

 

MIME type configuration   

<mime-mapping>   
    <extension>htm</extension>   
    <mime-type>text/html</mime-type>   
</mime-mapping>

 

 Specify the welcome page configuration 

  <welcome-file-list>   
      <welcome-file>index.jsp</welcome-file>   
      <welcome-file>index.html</welcome-file>   
      <welcome-file>index.htm</welcome-file>   
   </welcome-file-list>

 

configure error page

1. Configure error-page by error code 

error-page>   
    <error-code>404</error-code>   
    <location>/NotFound.jsp</location>   
</error-page>

 The above configuration is to jump to the error handling page NotFound.jsp when a 404 error occurs in the system.

2. Configure error-page by exception type 

<error-page>   
     <exception-type>java.lang.NullException</exception-type>   
     <location>/error.jsp</location>   
</error-page>

 The above configuration is to jump to the error handling page error.jsp when java.lang.NullException (that is, null pointer exception) occurs in the system

 

TLD configuration 

<taglib>   
     <taglib-uri>http://jakarta.apache.org/tomcat/debug-taglib</taglib-uri>   
     <taglib-location>/WEB-INF/jsp/debug-taglib.tld</taglib-location>   
</taglib>

 

If MyEclipse keeps reporting errors, you should put < taglib >  in  < jsp -   config >

<jsp-config>   
    <taglib>   
        <taglib-uri>http://jakarta.apache.org/tomcat/debug-taglib</taglib-uri>   
        <taglib-location>/WEB-INF/pager-taglib.tld</taglib-location>   
    </taglib>   
</jsp-config>

 

Resource management object configuration 

<resource-env-ref>   
     <resource-env-ref-name>jms/StockQueue</resource-env-ref-name>   
</resource-env-ref>

 

Resource Factory Configuration 

<resource-ref>   
     <res-ref-name>mail/Session</res-ref-name>   
     <res-type>javax.mail.Session</res-type>   
     <res-auth>Container</res-auth>   
 </resource-ref>

 

Configuring the database connection pool can be configured here:   

<resource-ref>   
     <description>JNDI JDBC DataSource of shop</description>   
     <res-ref-name>jdbc/sample_db</res-ref-name>   
     <res-type>javax.sql.DataSource</res-type>   
     <res-auth>Container</res-auth>   
</resource-ref>

 

 Security Restriction Configuration 

 

<security-constraint>   
      <display-name>Example Security Constraint</display-name>   
      <web-resource-collection>   
         <web-resource-name>Protected Area</web-resource-name>   
         <url-pattern>/jsp/security/protected/*</url-pattern>   
         <http-method>DELETE</http-method>   
         <http-method>GET</http-method>   
         <http-method>POST</http-method>   
         <http-method>PUT</http-method>   
      </web-resource-collection>   
      <auth-constraint>   
        <role-name>tomcat</role-name>   
        <role-name>role1</role-name>   
      </auth-constraint>   
</security-constraint>

 

 Login authentication configuration

<login-config>   
     <auth-method>FORM</auth-method>   
     <realm-name>Example-Based Authentiation Area</realm-name>   
     <form-login-config>   
        <form-login-page>/jsp/security/protected/login.jsp</form-login-page>   
        <form-error-page>/jsp/security/protected/error.jsp</form-error-page>   
     </form-login-config>   
</login-config>

 

Security roles: The security-role element gives a list of security roles that will appear in the role-name subelement of the security-role-ref element within the servlet element.

Declaring roles separately makes it easier for advanced IDEs to handle security information.

<security-role>   
     <role-name>tomcat</role-name>   
  </security-role>

 

Web environment parameters: The env-entry element declares the environment items of the web application 

  <env-entry>   
     <env-entry-name>minExemptions</env-entry-name>   
     <env-entry-value>1</env-entry-value>   
     <env-entry-type>java.lang.Integer</env-entry-type>   
  </env-entry>

 

EJB declaration 

  <ejb-ref>   
     <description>Example EJB reference</decription>   
     <ejb-ref-name>ejb/Account</ejb-ref-name>   
     <ejb-ref-type>Entity</ejb-ref-type>   
     <home>com.mycompany.mypackage.AccountHome</home>   
     <remote>com.mycompany.mypackage.Account</remote>   
  </ejb-ref>

 

Local EJB declaration

  <ejb-local-ref>   
     <description>Example Loacal EJB reference</decription>   
     <ejb-ref-name>ejb/ProcessOrder</ejb-ref-name>   
     <ejb-ref-type>Session</ejb-ref-type>   
     <local-home>com.mycompany.mypackage.ProcessOrderHome</local-home>   
     <local>com.mycompany.mypackage.ProcessOrder</local>   
  </ejb-local-ref>

 

 Placement DWR 

<servlet>   
      <servlet-name>dwr-invoker</servlet-name>   
      <servlet-class>uk.ltd.getahead.dwr.DWRServlet</servlet-class>   
 </servlet>   
 <servlet-mapping>   
      <servlet-name>dwr-invoker</servlet-name>   
      <url-pattern>/dwr/*</url-pattern>   
 </servlet-mapping>

 

Configure Struts 

    <display-name>Struts Blank Application</display-name>   
    <servlet>   
        <servlet-name>action</servlet-name>   
        <servlet-class>   
            org.apache.struts.action.ActionServlet   
        </servlet-class>   
        <init-param>   
            <param-name>detail</param-name>   
            <param-value>2</param-value>   
        </init-param>   
        <init-param>   
            <param-name>debug</param-name>   
            <param-value>2</param-value>   
        </init-param>   
        <init-param>   
            <param-name>config</param-name>   
            <param-value>/WEB-INF/struts-config.xml</param-value>   
        </init-param>   
        <init-param>   
            <param-name>application</param-name>   
            <param-value>ApplicationResources</param-value>   
        </init-param>   
        <load-on-startup>2</load-on-startup>   
    </servlet>   
    <servlet-mapping>   
        <servlet-name>action</servlet-name>   
        <url-pattern>*.do</url-pattern>   
    </servlet-mapping>   
    <welcome-file-list>   
        <welcome-file>index.jsp</welcome-file>   
    </welcome-file-list>   
  
    <!-- Struts Tag Library Descriptors -->   
    <taglib>   
        <taglib-uri>struts-bean</taglib-uri>   
        <taglib-location>/WEB-INF/tld/struts-bean.tld</taglib-location>   
    </taglib>   
    <taglib>   
        <taglib-uri>struts-html</taglib-uri>   
        <taglib-location>/WEB-INF/tld/struts-html.tld</taglib-location>   
    </taglib>   
    <taglib>   
    <taglib-uri>struts-nested</taglib-uri>   
    <taglib-location>/WEB-INF/tld/struts-nested.tld</taglib-location>   
    </taglib>   
    <taglib>   
        <taglib-uri>struts-logic</taglib-uri>   
        <taglib-location>/WEB-INF/tld/struts-logic.tld</taglib-location>   
    </taglib>   
    <taglib>   
        <taglib-uri>struts-tiles</taglib-uri>   
        <taglib-location>/WEB-INF/tld/struts-tiles.tld</taglib-location>   
    </taglib>

 

Configure Spring (basically all configured in Struts)

   <!-- Specify the location of the spring configuration file-->   
   <context-param>   
      <param-name>contextConfigLocation</param-name>   
      <param-value>   
       <!--Load multiple spring configuration files-->   
        /WEB-INF/applicationContext.xml, /WEB-INF/action-servlet.xml   
      </param-value>   
   </context-param>   
  
   <!-- Define SPRING listener, load spring -->   
  
  <listener>   
     <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>   
  </listener>   
  
  <listener>   
     <listener-class>   
       org.springframework.web.context.request.RequestContextListener   
     </listener-class>   
  </listener>