Use custom annotations for login interception control in SPRINGMVC

1:java annotations are used quite frequently, especially when building frameworks where the reflection of a class is used to obtain methods and properties.

There are four meta-annotations in Java: @Retention @Target @Document @Inherited;

1 @Retention: Where annotations are held2@Retention (Retentionpolicy.source)//annotations exist only in the source code and are not included in the class bytecode file3@Retention (Retentionpolicy.class)//The default retention policy, annotations are present in the class bytecode file, but are not available at run time .4@Retention (Retentionpolicy.runtime)//annotations exist in the class bytecode file and can be retrieved at run time through reflection5      　　 6 @Target: The purpose of the annotation7      　　　　　　　　 8@Target (Elementtype.type)//interfaces, classes, enumerations, annotations9@Target (Elementtype.field)//constants for fields, enumerationsTen@Target (Elementtype.method)//Method One@Target (Elementtype.parameter)//Method Parameters A@Target (Elementtype.constructor)//constructor Function -@Target (elementtype.local_variable)//Local Variables -@Target (Elementtype.annotation_type)//Annotations the@Target (Elementtype.package)///Bag -       - @Document: Note that the note will be included in the Javadoc -       +@Inherited: The description subclass can inherit the annotation from the parent class

To create a custom annotation class:

1  PackageCom.liveyc.eloan.util;2 3 ImportJava.lang.annotation.ElementType;4 Importjava.lang.annotation.Retention;5 ImportJava.lang.annotation.RetentionPolicy;6 ImportJava.lang.annotation.Target;7 8 /**9 * Login Tag RequiredTen  * @authorAdministrator One  * A  */ - @Target (Elementtype.method) - @Retention (retentionpolicy.runtime) the  Public@InterfaceRequirelogin { -  -}

2: Write Interceptor in Java interception is passed down so to return false do not continue to pass down the

1  PackageCom.liveyc.eloan.base.interceptor;2 3 Importjavax.servlet.http.HttpServletRequest;4 ImportJavax.servlet.http.HttpServletResponse;5 6 ImportOrg.springframework.web.method.HandlerMethod;7 ImportOrg.springframework.web.servlet.handler.HandlerInterceptorAdapter;8 9 ImportCom.liveyc.eloan.util.RequireLogin;Ten ImportCom.liveyc.eloan.util.UserContext; One  A /** - * Login Blocker -  *  the  * @authorAdministrator -  *  -  */ -  Public classLogininterceptorextendsHandlerinterceptoradapter { +  - @Override +      Public BooleanPrehandle (httpservletrequest request, AHttpServletResponse response, Object handler)throwsException { at         //processing handler; -         if(HandlerinstanceofHandlermethod) { -             //determine if there is a label on the current method; -Handlermethod HM =(Handlermethod) handler; -             if(Hm.getmethodannotation (Requirelogin.class) !=NULL -&& usercontext.getcurrent () = =NULL) { in                 //R If there is, determine whether the user is currently logged in, if not logged in, jump to the login page -Response.sendredirect ("/login.html"); to                 return false; +             } -         } the         return Super. Prehandle (Request, response, handler); *     } $ Panax Notoginseng}

3: Add in Spring's XML configuration file

1     <mvc:interceptors>2         <!--Configuring the Login blocker -3         <Mvc:interceptor>4             <mvc:mappingPath="/**" />5             <Beanclass= "Com.liveyc.eloan.base.interceptor.LoginInterceptor" />6         </Mvc:interceptor>7     </mvc:interceptors>

4: Add custom Annotations to methods that SPRINGMVC's controller layer needs to log in to access later @RequireLogin

1 @RequireLogin2@RequestMapping ("Personal")3  PublicString Personal (model model) {4Logininfo current =usercontext.getcurrent ();5Model.addattribute ("UserInfo", This. Userinfoservice.get (Current.getid ()));6Model.addattribute ("Account", This. Accountservice.get (Current.getid ()));7     return"Personal";8}

5: Start Project start test

Because it is not logged in, it jumps directly to the login page.

Access a method page with no custom annotations error

Log in after page normal access

Use custom annotations for login interception control in SPRINGMVC