springmvc里使用註解進行攔截器配置

springmvc本身不能像struts2那樣使用註解攔截action,這在使用中非常不方便,我們來擴展下springmvc,增加一個類,就可以實現註解攔截器.

首先把下面這個類拷貝進去:

package interceptor;

import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.springframework.web.method.HandlerMethod;

import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

public abstract class BaseInterceptor extends HandlerInterceptorAdapter {

public String success;

public String failed;

public boolean isMyHandler(Object handler) {

if (!(handler instanceof HandlerMethod))

return false;

HandlerMethod handlerMethod = (HandlerMethod) handler;

Interceptor interceptor = handlerMethod.getMethodAnnotation(Interceptor.class);

if (interceptor == null)

return false;

if (!interceptor.name().equals(this.getClass().getSimpleName()) && !interceptor.name().equals(this.getClass().getName()))

return false;

success = interceptor.success();

failed = interceptor.failed();

return true;

}

@Override

public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

if (isMyHandler(handler)) {

return runHandler(response, runHandler(request, response));

}

return super.preHandle(request, response, handler);

}

public abstract boolean runHandler(HttpServletRequest request, HttpServletResponse response);

/**

* 運行結果

*

* @param response

* @param isInterceptor

* 是否攔截,true攔截,跳轉向failed指向頁面,false:不攔截,跳轉向success指向頁面;

* success和failed為空時不做任何操作

* @return

* @throws Exception

*/

public boolean runHandler(HttpServletResponse response, boolean isInterceptor) throws Exception {

if (!isInterceptor) {

if (!success.equals("")) {

response.sendRedirect(success);

return false;

}

} else {

if (!failed.equals("")) {

response.sendRedirect(failed);

return false;

}

}

return true;

}

@Target(ElementType.METHOD)

@Retention(RetentionPolicy.RUNTIME)

public static @interface Interceptor {

public String name();

public String success() default "";

public String failed() default "";

}

}

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以上代碼僅支持spring3.1.6以上版本,低一些的版本趕快升級吧.說真的,如果不能註解攔截器,開發時候像是登錄驗證/許可權認證太費事了.

自己寫一個攔截器,繼承與上面的類,如下:

package interceptor;

import javax.annotation.Resource;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import service.UserServiceImpl;

public class LoginCheck extends BaseInterceptor {

@Resource

private UserServiceImpl userService;

@Override

public boolean runHandler(HttpServletRequest request, HttpServletResponse response) {

//.....判斷是否登陸,判斷是否有許可權等邏輯代碼

return false;

}

}

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在springmvc配置文件中配置攔截器:

<mvc:interceptors>

<mvc:interceptor>

<mvc:mapping path="/**" />

<bean class="interceptor.LoginCheck"></bean>

</mvc:interceptor>

</mvc:interceptors>

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攔截器配置為攔截所有controller.

在controller方法上寫

@Interceptor(name = "LoginCheck", failed = "/user/login")

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如:

@Interceptor(name = "LoginCheck", failed = "/user/login")

@RequestMapping("/user/del/{id}")

public void del(@PathVariable int id, HttpServletResponse response) throws IOException {

userService.del(id);

response.sendRedirect("/users/1");

}

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這樣在訪問del方法的時候,就會先運行logincheck攔截器,如果攔截器攔截了,就會跳轉到user/login頁面,是不是和struts2的攔截器一樣好用了?

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