我想创建自定义 Controller 方法参数注释。
关注这个问题How to pass a session attribute as method argument (parameter) with Spring MVC并遵循@Bozho的建议,我有这样的东西:
我的解析器
public class SessionAttributeAnnotationResolver implements WebArgumentResolver {
public Object resolveArgument(MethodParameter parameter,
NativeWebRequest request) throws Exception {
System.out.println("I am here");
Annotation[] parameterAnnotations = parameter.getParameterAnnotations();
Class<?> parameterType = parameter.getParameterType();
for (Annotation parameterAnnotation : parameterAnnotations) {
if (SessionAttribute.class.isInstance(parameterAnnotation)) {
SessionAttribute sessionAttribute = (SessionAttribute) parameterAnnotation;
String parameterName = sessionAttribute.value();
boolean required = sessionAttribute.required();
HttpServletRequest httprequest = (HttpServletRequest) request
.getNativeRequest();
HttpSession session = httprequest.getSession(false);
Object result = null;
if (session != null) {
result = session.getAttribute(parameterName);
}
if (result == null && required && session == null)
raiseSessionRequiredException(parameterName, parameterType);
if (result == null && required)
raiseMissingParameterException(parameterName, parameterType);
return result;
}
}
return WebArgumentResolver.UNRESOLVED;
}
protected void raiseMissingParameterException(String paramName,
Class<?> paramType) throws Exception {
throw new IllegalStateException("Missing parameter '" + paramName
+ "' of type [" + paramType.getName() + "]");
}
protected void raiseSessionRequiredException(String paramName,
Class<?> paramType) throws Exception {
throw new HttpSessionRequiredException(
"No HttpSession found for resolving parameter '" + paramName
+ "' of type [" + paramType.getName() + "]");
}
}
注释
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface SessionAttribute {
String value();
boolean required() default true;
}
简单的 Controller 来测试一切
@Controller
@RequestMapping("/test")
public class TestController {
@RequestMapping(method= RequestMethod.GET)
public String t(@SessionAttribute("userEntity") UserEntity e2,Model model,HttpServletRequest req){
System.out.println(req.getSession().getId());
UserEntity e=(UserEntity) req.getSession().getAttribute("userEntity");
System.out.println(e.getName());
System.out.println(e2.getName());
return "login";
}
}
最后是 Spring 配置
<beans:bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<beans:property name="customArgumentResolver" ref="sessionAttributeAnnotationResolver"/>
</beans:bean>
<beans:bean id="sessionAttributeAnnotationResolver" class="pl.meble.taboret.utils.SessionAttributeAnnotationResolver"/>
现在,一切对我来说似乎都很顺利,但我可能犯了一些愚蠢的错误,因为当 Controller 执行时,我得到了
F0B282C93B74F8FA3F21A51F46D4D4D5
username
null
最佳答案
在 Spring 3.1.0 中,ArgumentResolver 现在已更改为 HandlerMethodArgumentResolver
- 在此之前它曾经是 WebArgumentResolver
- 相关答案是 here
一旦您编写了一个与当前实现没有太大区别的新 HandlerMethodArgumentResolver 后,您可以通过以下方式注册它:
<mvc:annotation-driven>
<mvc:argument-resolvers>
<bean id="sessionAttributeAnnotationResolver" class="..SessionAttributeAnnotationResolver ">
</bean>
</mvc:argument-resolvers>
</mvc:annotation-driven>
关于Spring mvc - WebArgumentResolver 的实现,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12393937/