Spring MVC的 - 实施WebArgumentResolver的 [英] Spring mvc - implementation of WebArgumentResolver
问题描述
我想创建自定义的控制方法参数的注释。
开始关注此问题<一href=\"http://stackoverflow.com/questions/3621266/how-to-pass-a-session-attribute-as-method-argument-parameter-with-spring-mvc\">How通过会话属性作为方法参数（参数）与Spring MVC的并以下@Bozho建议，我有这样的事情：
我的解析器
公共类SessionAttributeAnnotationResolver实现WebArgumentResolver { 公共对象resolveArgument（MethodParameter参数，
NativeWebRequest要求）抛出异常{
的System.out.println（我在这里）;
注释[] = parameterAnnotations parameter.getParameterAnnotations（）;
类＆LT;＆GT;参数类型= parameter.getParameterType（）; 对于（译注parameterAnnotation：parameterAnnotations）{
如果（SessionAttribute.class.isInstance（parameterAnnotation））{
SessionAttribute sessionAttribute =（SessionAttribute）parameterAnnotation;
字符串参数名称= sessionAttribute.value（）;
布尔所需= sessionAttribute.required（）;
HttpServletRequest的HTT prequest =（HttpServletRequest的）要求
.getNativeRequest（）;
HttpSession的会议= HTT prequest.getSession（假）;
对象result = NULL;
如果（会话！= NULL）{
结果= session.getAttribute（参数名称）;
}
如果（结果== NULL和放大器;＆放大器;要求和放大器;＆安培;会议== NULL）
raiseSessionRequiredException（参数名称，参数类型）;
如果（结果== NULL和放大器;＆安培;需要）
raiseMissingParameterException（参数名称，参数类型）;
返回结果;
}
}
返回WebArgumentResolver.UNRESOLVED;
} 保护无效raiseMissingParameterException（字符串paramName配置，
类＆LT;＆GT; paramType）抛出异常{
抛出新IllegalStateException异常（缺少参数'+ paramName配置
+[+ paramType.getName（）+]）类型的;
} 保护无效raiseSessionRequiredException（字符串paramName配置，
类＆LT;＆GT; paramType）抛出异常{
抛出新HttpSessionRequiredException（
没有找到的HttpSession解决参数'+ paramName配置
+[+ paramType.getName（）+]）类型的;
}
}
注释
@Target（ElementType.PARAMETER）
@Retention（RetentionPolicy.RUNTIME）
公共@interface SessionAttribute {
字符串值（）;
布尔需要（）默认为true;
}
简单的控制器来检验一切
@Controller
@RequestMapping（/测试）
公共类{的TestController @RequestMapping（方法= RequestMethod.GET）
公共串T（@SessionAttribute（userEntity）UserEntity E2，型号model，HttpServletRequest的REQ）{
的System.out.println（req.getSession（）的getId（））;
UserEntity E =（UserEntity）req.getSession（）的getAttribute（userEntity）;
的System.out.println（e.getName（））;
的System.out.println（e2.getName（））;
返回登录;
}
}
最后，Spring配置
＆LT;豆类：bean类=org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter＆GT;
＆LT;豆类：属性名=customArgumentResolverREF =sessionAttributeAnnotationResolver/＆GT;
＆LT; /豆：豆＆GT;
＆LT;豆类：豆类ID =sessionAttributeAnnotationResolver级=pl.meble.taboret.utils.SessionAttributeAnnotationResolver/＆GT;
现在，一切似乎都为了我，但可能有一些愚蠢的错误，我做的，因为在执行控制器后，我得到
F0B282C93B74F8FA3F21A51F46D4D4D5
用户名
空值
使用Spring 3.1.0的ArgumentResolver现已更改为 HandlerMethodArgumentResolver - 在此之前，它曾经是 WebArgumentResolver - 相关答案是<一个href=\"http://stackoverflow.com/questions/12357817/upgrading-to-spring-3-1-seems-to-break-my-customwebargumentresolver/12358370#12358370\">here
一旦你已经写了一个新的HandlerMethodArgumentResolver这是不是从你当前的实现非常不同，你可以用这种方式进行注册：
＆LT; MVC：注解驱动＆GT;
＆LT; MVC：参数-解析器＆GT;
＆LT;豆的id =sessionAttributeAnnotationResolver级=.. SessionAttributeAnnotationResolver＆GT;
＆LT; /豆＆GT;
＆LT; / MVC：参数-解析器＆GT;
＆LT; / MVC：注解驱动＆GT;
I wanted to create custom controller method argument annotation.
Following this question How to pass a session attribute as method argument (parameter) with Spring MVC and following @Bozho advice I have something like this:
my resolver
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() + "]");
}
}
the annotation
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface SessionAttribute {
String value();
boolean required() default true;
}
simple controller to test everything
@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";
}
}
and finally, Spring configuration
<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"/>
now, everything seems in order to me, but there is probably some silly mistake that I done, because when controller is executed, I am getting
F0B282C93B74F8FA3F21A51F46D4D4D5
username
null
With Spring 3.1.0 the ArgumentResolver has now changed to HandlerMethodArgumentResolver - prior to that it used to be WebArgumentResolver - a related answer is here
Once you have written a new HandlerMethodArgumentResolver which is not very different from your current implementation you can register it this way:
<mvc:annotation-driven>
<mvc:argument-resolvers>
<bean id="sessionAttributeAnnotationResolver" class="..SessionAttributeAnnotationResolver ">
</bean>
</mvc:argument-resolvers>
</mvc:annotation-driven>
这篇关于Spring MVC的 - 实施WebArgumentResolver的的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
