java - 如何将自定义版本的 WebDataBinder 注入(inject) Spring 3 MVC？

Question

我编写了 WebDataBinder 的自定义实现。将来我想增强它，以便它在类本身上查找注释，并确定它是否应该将数据绑定(bind)到它。

如何将此类注入(inject)到 Spring 上下文中以代替 WebDataBinder？

我想要的是，如果我运行这段代码，我的 WebDataBinder 版本将被注入(inject)，而不是默认的 Spring 版本。

@Controller
public class MyFormController {

    @InitBinder
    public void initBinder(WebDataBinder binder) {
        // ...
    }

    // ...
}

我自定义的 WebDataBinder 实现。它让我可以排除按类而不是按方法名称的数据绑定(bind)。

    package com.companyname.spring;

    import org.springframework.beans.MutablePropertyValues;
    import org.springframework.util.StringUtils;
    import org.springframework.web.bind.WebDataBinder;

    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.List;

    public class CustomDataBinder extends WebDataBinder {

        List<Class> disallowedClasses = new ArrayList<>();

        public CustomDataBinder(Object target) {
            super(target);
        }

        public CustomDataBinder(Object target, String objectName) {
            super(target, objectName);
        }

        public CustomDataBinder disallowClass(Class... classes) {
            Collections.addAll(disallowedClasses, classes);
            return this;
        }

        @Override
        protected void doBind(MutablePropertyValues mpvs) {
            if(disallowedClasses.contains(getTarget().getClass())) {
                if (logger.isDebugEnabled()) {
                    logger.debug("DataBinder will not bind class [" + getTarget().getClass().getSimpleName() + "] because it appears in the list of disallowed classes [" + StringUtils.collectionToCommaDelimitedString(disallowedClasses) + "]");
                }
            } else {
                super.doBind(mpvs);
            }
        }
    }

编辑1

第一步，AsyncSupportConfigurer 有问题

@Configuration
@ComponentScan(basePackageClasses = RootContextConfig.class)
@EnableTransactionManagement
@EnableWebSecurity
@EnableAsync
@EnableSpringConfigured
@EnableLoadTimeWeaving
public class RootContextConfig extends WebMvcConfigurationSupport {

    @Bean
    public RequestMappingHandlerAdapter requestMappingHandlerAdapter() {
        List<HandlerMethodArgumentResolver> argumentResolvers = new ArrayList<HandlerMethodArgumentResolver>();
        addArgumentResolvers(argumentResolvers);

        List<HandlerMethodReturnValueHandler> returnValueHandlers = new ArrayList<HandlerMethodReturnValueHandler>();
        addReturnValueHandlers(returnValueHandlers);

        RequestMappingHandlerAdapter adapter = new CustomRequestMappingHandlerAdapter();
        adapter.setContentNegotiationManager(mvcContentNegotiationManager());
        adapter.setMessageConverters(getMessageConverters());
        adapter.setWebBindingInitializer(getConfigurableWebBindingInitializer());
        adapter.setCustomArgumentResolvers(argumentResolvers);
        adapter.setCustomReturnValueHandlers(returnValueHandlers);

        AsyncSupportConfigurer configurer = new AsyncSupportConfigurer();
        configureAsyncSupport(configurer);


//All the methods called off of configurer are giving me errors because they have protected level access. I'm not really sure how they're being called in the code I copied this from.
        if (configurer.getTaskExecutor() != null) {
            adapter.setTaskExecutor(configurer.getTaskExecutor());
        }
        if (configurer.getTimeout() != null) {
            adapter.setAsyncRequestTimeout(configurer.getTimeout());
        }
        adapter.setCallableInterceptors(configurer.getCallableInterceptors());
        adapter.setDeferredResultInterceptors(configurer.getDeferredResultInterceptors());

        return adapter;
    }

自定义RequestMappingHandlerAdapter

package com.companyname.dirtylibs.spring;

import org.springframework.web.method.annotation.InitBinderDataBinderFactory;
import org.springframework.web.method.support.InvocableHandlerMethod;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
import org.springframework.web.servlet.mvc.method.annotation.ServletRequestDataBinderFactory;

import java.util.List;

public class CustomRequestMappingHandlerAdapter extends RequestMappingHandlerAdapter {
    @Override
    protected InitBinderDataBinderFactory createDataBinderFactory(List<InvocableHandlerMethod> binderMethods) throws Exception {
        return new CustomInitBinderDataBinderFactory(binderMethods, getWebBindingInitializer());
    }
}

自定义 InitBinderDataBinderFactory

package com.companyname.dirtylibs.spring;

import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.support.WebBindingInitializer;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.bind.support.WebRequestDataBinder;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.annotation.InitBinderDataBinderFactory;
import org.springframework.web.method.support.InvocableHandlerMethod;
import org.springframework.web.servlet.mvc.method.annotation.ServletRequestDataBinderFactory;

import java.util.List;

public class CustomInitBinderDataBinderFactory extends InitBinderDataBinderFactory {

    /**
     * Create a new instance.
     *
     * @param binderMethods {@code @InitBinder} methods, or {@code null}
     * @param initializer   for global data binder intialization
     */
    public CustomInitBinderDataBinderFactory(List<InvocableHandlerMethod> binderMethods, WebBindingInitializer initializer) {
        super(binderMethods, initializer);
    }

    @Override
    protected CustomDataBinder createBinderInstance(Object target, String objectName, NativeWebRequest webRequest) throws Exception {
        return new CustomDataBinder(target, objectName);
    }
}

Answer 1

这不是一项简单的任务。 Spring 允许进行大量定制，但是，该死的，这种改变并不有趣。

您需要扩展 RequestMappingHandlerAdapter 类并覆盖 following method

/**
 * Template method to create a new InitBinderDataBinderFactory instance.
 * <p>The default implementation creates a ServletRequestDataBinderFactory.
 * This can be overridden for custom ServletRequestDataBinder subclasses.
 * @param binderMethods {@code @InitBinder} methods
 * @return the InitBinderDataBinderFactory instance to use
 * @throws Exception in case of invalid state or arguments
 */
protected InitBinderDataBinderFactory createDataBinderFactory(List<InvocableHandlerMethod> binderMethods)
        throws Exception {

    return new ServletRequestDataBinderFactory(binderMethods, getWebBindingInitializer());
}

而不是返回 ServletRequestDataBinderFactory ，您需要返回自定义 InitBinderDataBinderFactory返回您的自定义 WebDataBinder实例。

此更改意味着您不能使用默认的 @EnableWebMvc或 <mvc:annotation-driven/>配置。那是因为他们使用 RequestMappingHandlerAdapter默认情况下，但您需要注册自己的类(class)。

但是，您可以覆盖 @Bean注释 WebMvcConfigurationSupport#requestMappingHandlerAdapter()方法并提供您自己的实现以返回您自己的类型。查看该实现的提示。