SPRINGMVC Interceptor Use

Source Address

Interceptor Interceptor

The interceptor is the first door of the URL request, and all requests go through the interceptor before interceptor entering controller ;
Below, an annotation method is used to intercept all requests that require login to be initiated and redirect illegal requests to the login interface

Basic configuration of XML files

<!--配置拦截器, 多个拦截器,顺序执行 --><mvc:interceptors>    <mvc:interceptor>        <!-- 匹配的是url路径， 如果不配置或/**,将拦截所有的Controller -->        <mvc:mapping path="/**" />        <!--resource不拦截-->        <mvc:exclude-mapping path="/asset/**"/>        <mvc:exclude-mapping path="/assets/**"/>        <!--聊天室websocket不拦截-->        <mvc:exclude-mapping path="/sockjs/websocket"/>        <mvc:exclude-mapping path="/websocket"/>        <bean class="com.iss.blog.interceptor.AccessControlInterceptor"/>    </mvc:interceptor>    <!-- 当设置多个拦截器时，先按顺序调用preHandle方法，然后逆序调用每个拦截器的postHandle和afterCompletion方法 --></mvc:interceptors><!-- 静态资源访问（不拦截此目录下的东西的访问）  --><mvc:resources location="/asset/"  mapping="/asset/**" /><mvc:resources location="/assets/"  mapping="/assets/**" />

Key implementationsHandlerInterceptorAdapter

Public abstract class Abstractinterceptor extends Handlerinterceptoradapter {/** * have publicpage annotations * @param h Andlermethod * @return */protected Boolean ispublicpage (Handlermethod handlermethod) {if (Handlermetho        D==null) return false;        Publicpage publicpage = handlermethod.getmethodannotation (Publicpage.class);        if (publicpage!=null) {return true;    } return false; }/** * Whether a request is AJAX request * @param request * @return */protected Boolean isajaxrequest (httpservletreques        T request) {String RequestType = Request.getheader ("X-requested-with");            if ("XMLHttpRequest". Equals (RequestType)) {System.out.println ("is AJAX request");        return true;            }else{System.out.println ("is not AJAX request");        return false;     }}} public class Accesscontrolinterceptor extends Abstractinterceptor {/** * The following paragraph refers to a piece of article, because the original text is not found, so the reference link is not affixed * Called before the business processor processes the request * if return false * from the current interceptor executes all interceptors aftercompletion (), and then exits the interceptor chain * If True * executes the next interceptor until the Some interceptors are executed. * Then execute the intercepted controller * and then enter the Interceptor chain, * go back from the last interceptor to execute all posthandle () * and then go backwards from the last interceptor to execute all a  Ftercompletion () */@Override public boolean prehandle (HttpServletRequest request, httpservletresponse response, Object handler) throws Exception {if (handler instanceof Handlermethod &&ispublicpage ((handlermethod) ha        Ndler)) {return true;            } if (no login) {PrintWriter out = Response.getwriter ();            Out.append ("{' ResultCode ': 1012, ' resultmessage ': ' Wrong Request '}"); if (!isajaxrequest (Request)) {//Here the request is forwarded to the login interface Request.getrequestdispatcher ("/login"). Forward (req            Uest, response);        } return false;    }else return true; /** * After the business processor processes the request execution, the actions performed before the view is generated * can include data in the Modelandview, such as whenFormer time */@Override public void Posthandle (HttpServletRequest request, httpservletrespons E response, Object handler, Modelandview Modelandview) throws Exception {}/** * in dis Patcherservlet is called after fully processing the request, can be used to clean up resources, etc. * * When an interceptor throws an exception, all interceptors are executed back from the current Interceptor aftercompletion () */@Override Publi c void Aftercompletion (HttpServletRequest request, httpservletresponse response, Object Han Dler, Exception ex) throws Exception {}}

Definitions of annotations

@Target({ElementType.METHOD, ElementType.ANNOTATION_TYPE})@Retention(RetentionPolicy.RUNTIME)@Documentedpublic @interface PublicPage {    String value() default "";}

This way, in addition to the @RequestMapping @PublicPage representative, so that the route does not need to log on can be requested, otherwise you need to log in to request to
For example, login page:

@PublicPage@RequestMapping("/login")public  String loginPage(){    return "frontend/account/login";}

Must be an AJAX request to be accessible

SPRINGMVC Interceptor Use