您可以通过创建ELResolver处理默认方法的自定义实现来解决此问题。我在这里所做的实现可以扩展SimpleSpringBeanELResolver。这是Spring的实现，ELResolver但没有Spring，相同的想法应该是相同的。
此类查找在bean的接口上定义的bean属性签名，并尝试使用它们。如果在接口上未找到bean prop签名，它将继续按照默认行为链发送它。
import org.apache.commons.beanutils.PropertyUtils;
import org.springframework.beans.factory.beanfactory;
import org.springframework.beans.factory.access.el.SimpleSpringBeanELResolver;
import javax.el.ELContext;
import javax.el.ELException;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.util.Optional;
import java.util.stream.Stream;
/**
* Resolves bean properties defined as default interface methods for the ELResolver.
* Retains default SimpleSpringBeanELResolver for anything which isn't a default method.
*
* Created by nstuart on 12/2/2016.
*/
public class DefaultMethodELResolver extends SimpleSpringBeanELResolver {
/**
* @param beanfactory the Spring beanfactory to delegate to
*/
public DefaultMethodELResolver(beanfactory beanfactory) {
super(beanfactory);
}
@Override
public Object getValue(ELContext elContext, Object base, Object property) throws ELException {
if(base != null && property != null) {
String propStr = property.toString();
if(propStr != null) {
Optional<Object> ret = attemptDefaultMethodInvoke(base, propStr);
if (ret != null) {
// notify the ELContext that our prop was resolved and return it.
elContext.setPropertyResolved(true);
return ret.get();
}
}
}
// delegate to super
return super.getValue(elContext, base, property);
}
/**
* Attempts to find the given bean property on our base object which is defined as a default method on an interface.
* @param base base object to look on
* @param property property name to look for (bean name)
* @return null if no property Could be located, Optional of bean value if found.
*/
private Optional<Object> attemptDefaultMethodInvoke(Object base, String property) {
try {
// look through interfaces and try to find the method
for(Class<?> intf : base.getClass().getInterfaces()) {
// find property descriptor for interface which matches our property
Optional<PropertyDescriptor> desc = Stream.of(PropertyUtils.getPropertyDescriptors(intf))
.filter(d->d.getName().equals(property))
.findFirst();
// ONLY handle default methods, if its not default we dont handle it
if(desc.isPresent() && desc.get().getReadMethod() != null && desc.get().getReadMethod().isDefault()) {
// found read method, invoke it on our object.
return Optional.ofNullable(desc.get().getReadMethod().invoke(base));
}
}
} catch (InvocationTargetException | illegalaccessexception e) {
throw new RuntimeException("Unable to access default method using reflection", e);
}
// no value found, return null
return null;
}
}
然后，您需要ELResolver在您的应用程序中的某个地方注册。就我而言，我使用的是Spring的Java配置，因此我需要以下内容：
@Configuration
...
public class SpringConfig extends WebMvcConfigurationSupport {
...
@Override
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
...
// add our default method resolver to our ELResolver list.
JspApplicationContext jspContext = JspFactory.getDefaultFactory().getJspApplicationContext(getServletContext());
jspContext.addELResolver(new DefaultMethodELResolver(getApplicationContext()));
}
}
我不能100％地确定这是否是添加我们的解析器的适当位置，但是它确实可以正常工作。您也可以在以下期间加载ELResolverjavax.servlet.servletcontextlistener.contextInitialized
这是ELResolver参考资料：http ://docs.oracle.com/javaee/7/api/javax/el/ELResolver.html
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