如何在 Java 配置中使用 delegatingFilterproxy?

问题描述

DelegatingFilterProxy 有两个构造函数，我可以在我的应用程序中使用

DelegatingFilterProxy has two constructors that I can use in my application

new DelegatingFilterProxy(String beanName);
new DelegatingFilterProxy(Filter delegate);

在我的 webappIntializer 中，我有以下内容.(请参阅下面的完整代码).

In my webappIntializer, I have the following. (please see below for full code).

servletContext.addFilter("counterMetricsFilter", new DelegatingFilterProxy("counterMetricsFilter").addMappingForUrlPatterns(null,
                false, MAPPING_URL);

我不确定 DelegatingFilterProxy 在我的情况下是否按预期运行.

I am not sure if DelegatingFilterProxy is functioning as expected in my case.

控制器

@Controller
@RequestMapping("/counter")
public class CounterController {

@Autowired
CounterManager manager;

 @RequestMapping(value = "/counterMetrics", method = RequestMethod.GET)
    @ResponseBody
    public Map getFeatureStatus(final HttpServletResponse response) {
        System.out.println("returning feautre status");
        return manager.getQueryCounts();
    }
}

经理

@Service
public class CounterManager {

private Map<String,Integer> queryCounts =
            new ConcurrentHashMap<String,Integer>(1000);

int threshold;
long timestamp;

 @Autowired
  public CounterManager(@Value("${healthThreshold: 10}")
                                 int threshold) {
      this.threshold = threshold * MEGABYTES;
      this.timestamp = System.currentTimeMillis();
  }


 public void incrementRequestCounter(String urlPath){
     Integer oldVal, newVal;
     do {
       oldVal = queryCounts.get(model);
       newVal = (oldVal == null) ? 1 : (oldVal + 1);
     } while (!queryCounts.replace(model, oldVal, newVal));
 }

public Map<StatusUrlModel, Integer> getQueryCounts() {
    return queryCounts;
}

}

过滤器

@Order(Ordered.HIGHEST_PRECEDENCE)
@Component(value="counterMetricsFilter")
public class CounterMetricsFilter extends OncePerRequestFilter {

    @Autowired
    CounterManager manager;

    @Override
    protected void doFilterInternal(HttpServletRequest request,
            HttpServletResponse response, FilterChain chain) throws ServletException,
            IOException {
        String path = new UrlPathHelper().getPathWithinApplication(request);
        try {
            chain.doFilter(request, response);
        }
        finally {
            recordMetrics(request, path);
        }
    }

   private void recordMetrics(String path) {
        try {
        manager.incrementRequestCounter(url);
        }
        catch (Exception ex){
            System.out.println("exception is thrown " + ex.getCause());
            ex.printStackTrace();
        }
    }
}

DelegatingFilterProxy

public class myAppWebAppInitializer implements WebApplicationInitializer {

             private static final String CONFIG_LOCATION = "com.myapp.sample.config";
            public static final String MAPPING_URL = "/*";

            @Override
            public void onStartup(ServletContext servletContext) throws ServletException {

     AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
    context.setConfigLocation(CONFIG_LOCATION);

                servletContext.addListener(new ContextLoaderListener(context));

                servletContext.addFilter("counterMetricsFilter", new DelegatingFilterProxy("counterMetricsFilter").addMappingForUrlPatterns(null,
            false, MAPPING_URL);

                ServletRegistration.Dynamic dispatcher = servletContext.addServlet("DispatcherServlet", new DispatcherServlet(
                        context));
                dispatcher.setLoadOnStartup(1);
                dispatcher.addMapping(MAPPING_URL);
            }

    }

注意:容器启动正常.请求顺利通过.因为上面 CounterMetricsFilter 中的这一行 manager.incrementRequestCounter(url) 抛出异常，我正在捕获它，我看到空响应.我怀疑 delegateFilterProxy 没有正确autowiring.

NOTE: The container start-up fine. Requests go through fine. because this line manager.incrementRequestCounter(url) in CounterMetricsFilter above is throwing exception, and I am catching it, I see empty response.I suspect delegateFilterProxy is not autowiring properly.

另请注意，manager bean 是在应用程序上下文中加载的，因为我可以在 CounterController 中检查 bean.

Also Note that manager bean is loaded in Application Context because I can inspect the bean in CounterController.

我无法修复它.这里的任何提示都会非常有帮助.

I am unable to fix it. Any tips here would be very helpful.

编辑

通过更改为 constructor injection 而不是 CounterMetricsFilter 中的字段注入，我得到以下异常.

by changing to constructor injection instead of field injection in CounterMetricsFilter, I get the following exception.

//我去掉了上面的无参数构造函数@自动连线公共 CounterMetricsFilter(HealthManager healthManager){this.healthManager=healthManager;}

//I removed the no-arg constructor above @Autowired public CounterMetricsFilter(HealthManager healthManager){ this.healthManager=healthManager; }

堆栈跟踪

SEVERE: Exception starting filter counterMetricsFilter
org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'counterMetricsFilter' is defined
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:638)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1159)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:282)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:979)
    at org.springframework.web.filter.DelegatingFilterProxy.initDelegate(DelegatingFilterProxy.java:324)
    at org.springframework.web.filter.DelegatingFilterProxy.initFilterBean(DelegatingFilterProxy.java:235)
    at org.springframework.web.filter.GenericFilterBean.init(GenericFilterBean.java:199)
    at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:281)
    at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:111)
    at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4775)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5452)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633)
    at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1113)
    at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1671)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
  [1]: http://stackoverflow.com/questions/32573742/why-is-autowired-bean-null-in-filter-in-this-spring-application

推荐答案

我在上面的代码片段中没有看到配置类本身，所以列出了如何使 DelegatingFilterProxy 与 Spring 一起工作的通用解决方案Java 配置.

I don't see configuration class itself among the code snippets above, so listing the general solution how to make DelegatingFilterProxy work with Spring Java Config.

初始化程序

public class MyWebAppInitializer implements WebApplicationInitializer {
    ...
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        ...
        servletContext.addFilter("myFilter", new DelegatingFilterProxy("myFilter"))
                .addMappingForUrlPatterns(null, true, "/*");
        ...
    }
    ...
}

过滤

public class MyFilter implements Filter {
    ...
    // I added this parameter just as example of how Spring-managed dependencies
    // could be injected. Note, there is no any annotations in this class.
    private String someParameter;
    public MyFilter(String someParameter) {
        this.someParameter = someParameter;
    }
    ...
}

配置

@Configuration
@EnableWebMvc
@PropertySource(value = {
        "classpath:my.properties"
})
@Import({
        PropertySourcesPlaceholderConfigurer.class
})
public class MyConfig {
    ...
    @Bean
    public MyFilter myFilter(@Value("${someParameter}") String someParameter) {
        return new MyFilter(someParameter);
    }
    ...
}

希望它对某人有用.

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