java-春季移动-拦截器没有应用？设备为空

发布时间：2020-12-15 01:21:18 所属栏目：大数据来源：网络整理

导读：我正在尝试使用Spring Mobile,但似乎无法使基本示例正常工作.我觉得我缺少一些愚蠢的简单东西,但我不知道它是什么.这就是我所拥有的在web.xml中 context-param param-namecontextConfigLocation/param-name param-value /WEB-INF/applicationContext.xml /p

我正在尝试使用Spring Mobile,但似乎无法使基本示例正常工作.我觉得我缺少一些愚蠢的简单东西,但我不知道它是什么.这就是我所拥有的…

在web.xml中

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>
        /WEB-INF/applicationContext.xml
    </param-value>
</context-param> 
<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<filter>
    <filter-name>deviceResolverRequestFilter</filter-name>
    <filter-class>org.springframework.mobile.device.DeviceResolverRequestFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>deviceResolverRequestFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

在applicationContext.xml中

<beans:beans xmlns="http://www.springframework.org/schema/mvc"
        xmlns:beans="http://www.springframework.org/schema/beans"
        xmlns:device="http://www.springframework.org/schema/mobile/device"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
        xsi:schemaLocation="http://www.springframework.org/schema/mvc 
                http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
                http://www.springframework.org/schema/beans 
                http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
                http://www.springframework.org/schema/mobile/device 
                http://www.springframework.org/schema/mobile/device/spring-mobile-device-1.0.xsd">

    <!-- Interceptors that execute common control logic across multiple requests -->
    <interceptors>
        <!-- Detects the client's Device -->
        <beans:bean class="org.springframework.mobile.device.DeviceResolverHandlerInterceptor" />
    </interceptors>

</beans:beans>

在我的Java课中：

public class TestAction extends ActionSupport implements ServletRequestAware {

    // So that we can lookup the current Device 
    private HttpServletRequest request;

    public void setServletRequest(HttpServletRequest request) {
        this.request = request;
    }

    @Override
    public String execute() {
        Device currentDevice = DeviceUtils.getCurrentDevice(request);
        if (currentDevice.isMobile()) // <-- fails here with NPE

为什么未设置设备并导致其为空？

编辑：
日志文件似乎表明设置拦截器存在问题,但我仍然不确定出错的地方.

2012-05-29 09:36:36,696 DEBUG [ConstructorResolver.java:201] :
Ignoring constructor [public
org.springframework.web.servlet.handler.MappedInterceptor(java.lang.String[],org.springframework.web.context.request.WebRequestInterceptor)]
of bean ‘org.springframework.web.servlet.handler.MappedInterceptor#0’:
org.springframework.beans.factory.UnsatisfiedDependencyException:
Error creating bean with name
‘org.springframework.web.servlet.handler.MappedInterceptor#0’:
Unsatisfied dependency expressed through constructor argument with
index 1 of type
[org.springframework.web.context.request.WebRequestInterceptor]: Could
not convert constructor argument value of type
[org.springframework.mobile.device.DeviceResolverHandlerInterceptor]
to required type
[org.springframework.web.context.request.WebRequestInterceptor]:
Failed to convert value of type
‘org.springframework.mobile.device.DeviceResolverHandlerInterceptor’
to required type
‘org.springframework.web.context.request.WebRequestInterceptor’;
nested exception is java.lang.IllegalStateException: Cannot convert
value of type
[org.springframework.mobile.device.DeviceResolverHandlerInterceptor]
to required type
[org.springframework.web.context.request.WebRequestInterceptor]: no
matching editors or conversion strategy found

最佳答案

我对此进行了查看,并设法使其自行工作.所以我有几点意见.

1a)我认为过滤器和拦截器都不是必需的. I’ve just used the Filter and that was enough.

1b)拦截器(如果使用)should be configured in a DispatcherServlet xml config file.您看起来像从ActionSupport的使用中使用的是Struts,这是正确的吗？如果是这样,您(可能)将没有DispatcherServlet,因此我认为此配置无法按预期工作.我认为这就是为什么要获取堆栈跟踪的原因.

2)我将在org.springframework.mobile.device.DeviceResolverRequestFilter.doFilterInternal添加一个断点,以确保它正在执行.

3)我将检查Struts对ServletRequest的操作是否“有趣”,并以某种方式对您隐藏“currentDevice” request attribute.实际上,如果可能的话,我会将您的代码移植到Vanilla Spring.

4)也许您可以在execute方法中使用ServletActionContext.getRequest,看看是否可行,和/或将返回的请求与setServletRequest中的设置进行比较.

使用Spring MVC,这对我有效.我的项目称为spring-mobile-test,“ spring-mobile-test”是其上下文根：

web.xml：

<?xml version="1.0" encoding="utf-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/applicationContext.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <filter>
        <filter-name>deviceResolverRequestFilter</filter-name>
        <filter-class>org.springframework.mobile.device.DeviceResolverRequestFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>deviceResolverRequestFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <servlet>
        <servlet-name>mvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>mvc</servlet-name>
        <url-pattern>/mvc/*</url-pattern>
    </servlet-mapping>
</web-app>

applicationContext.xml为空.

mvc-servlet.xml：

<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:beans="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.1.xsd">

    <context:component-scan base-package="temp" />

</beans>

temp.TestController：

package temp;

import javax.servlet.http.HttpServletRequest;

import org.apache.log4j.Logger;
import org.springframework.mobile.device.Device;
import org.springframework.mobile.device.DeviceUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class TestController {
    private static final Logger logger = Logger.getLogger(TestController.class);

    @RequestMapping("/")
    public @ResponseBody
    String home(HttpServletRequest req) {
        Device device = DeviceUtils.getCurrentDevice(req);
        String msg = "";
        if (device.isMobile()) {
            msg = "Hello mobile user!";
        } else {
            msg = "Hello desktop user!";
        }
        logger.info(msg);
        return msg;
    }
}

当我浏览到URL http：// localhost / spring-mobile-test / mvc /时,浏览器显示以下文本：

Hello desktop user!

（编辑：李大同）

【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容!