public class UserAction{
private UserData user;
//getter, setter
public String Load() {
user = UserDao.getInstance().getItem(getUserContext().getId());
request.getSession().setAttribute("item", user);
return super.Load();
}
}
public class PropertyAction {
private List <PropertyData> propertyList;
//getter, setter
#Override
public String execute() throws Exception {
propertyList=PropertyDao.getInstance().getItems();
return "list";
}
}
jsp:
<s:iterator value="propertyList" var="item">
${item.name}
${item.thema}
${item.desc}
</s:iterator>
I want to show very strange behaviour of Struts2.
I click property link -> then run PropertyAction.execute() and it display above jsp.
I click user link -> then run UserAction.Load()
I click property link -> then run PropertyAction.execute() and error has been shown "UserData has no property thema".
I spy what happened and I notice that I set setAttribute with name "item". So if I use var="item" in my iterator in jsp, it doesn not use value from propertyList but from session !
My question is it is correct behaviour ?
This is defined behavior; whether or not it's "correct" is debatable.
Because you're using JSP EL, the Struts request wrapper is responsible for resolving JSP EL expressions. The normal application scopes are searched first (e.g., application, session, request). If nothing is found, only then will the value stack be queried for matching expressions.
If you accessed item via non-JSP EL means, e.g., the <s:property> tag, only the value stack would be queried, and you'd get the expected behavior.
When you mix ELs results are not always what you'd expect, so you must be aware how the frameworks in question relate to each other.
I have the following domain class:
package com.example
class Location {
String state
def getStatesList(){
def states = ['AL','AK','AZ','AR','CA','CO','CT',
'DC','DE','FL','GA','HI','ID','IL','IN','IA',
'KS','KY','LA','ME','MD','MA','MI','MN','MS',
'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
'ND','OH','OK','OR','PA','RI','SC','SD','TN',
'TX','UT','VT','VA','WA','WV','WI','WY']
return states
}
}
In my gsp, I am trying to display the state list in a select dropdown as such
<g:select name="location.state" class="form-control" from="${com.example.Location?.getStatesList()}" value="${itemInstance?.location?.state}" noSelection="['': '']" />
In doing so, I am receiving "missing method exception"
If I change the method with list, I no longer receive the error, but I don't want that.
from="${com.example.Location?.list()}" // works
from="${com.example.Location?.getStatesList()}" // does not work
Any help is greatly appreciated.
As dmahaptro said, you can correct this issue by making getStatesList() a static method.
class Location {
String state
static List<String> getStatesList() {
['AL','AK','AZ','AR','CA','CO','CT',
'DC','DE','FL','GA','HI','ID','IL','IN','IA',
'KS','KY','LA','ME','MD','MA','MI','MN','MS',
'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
'ND','OH','OK','OR','PA','RI','SC','SD','TN',
'TX','UT','VT','VA','WA','WV','WI','WY']
}
}
Then you'll be able to execute Location.statesList or Location.getStatesList().
Alternative
I think a cleaner alternative is using a final constant:
class Location {
String state
static final List<String> STATES =
['AL','AK','AZ','AR','CA','CO','CT',
'DC','DE','FL','GA','HI','ID','IL','IN','IA',
'KS','KY','LA','ME','MD','MA','MI','MN','MS',
'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
'ND','OH','OK','OR','PA','RI','SC','SD','TN',
'TX','UT','VT','VA','WA','WV','WI','WY']
}
Then you can access the list the same way: Location.STATES. The difference is that the all-caps name implies a value that does not change (and does not require accessing the database).
list() is a method on the domain object's metaclass. In order to do what you're trying to do you'd have to instantiate an instance of Location (or add to the metaclass). I'd personally use an Enum instead if I were you.
You have to make getStatesList() static because you are not accessing an instance of the Location class.
I'm using Grails 2.3.7 and have a controller method which binds the request to a command class. One of the fields in the command class is a String array, as it expects multiple params with the same name to be specified - e.g. ?foo=1&foo=2&foo=3&bar=0.
This works fine most of the time. The one case where it fails is if the param value contains a comma - e.g. ?foo=val1,val2&foo=val3,val4. In this case I'm getting an array with 4 values: ["val1","val2","val3","val4"], not the intended output of ["val1,val2","val1,val2"]. URL escaping/encoding the comma does not help and in my cases the param value is surrounded by quote characters as well (foo=%22a+string+with+commas,+etc%22).
I had a similar problem with Spring 3.x which I was able to solve: How to prevent parameter binding from interpreting commas in Spring 3.0.5?. I've attempted one of the answers by adding the following method to my controller:
#InitBinder
public void initBinder(WebDataBinder binder) {
binder.registerCustomEditor(String[].class, new StringArrayPropertyEditor(null));
}
However this didn't work.
I also tried specifying a custom conversion service, based on the comment in https://jira.grails.org/browse/GRAILS-8997.
Config/spring/resources.groovy:
beans = {
conversionService (org.springframework.context.support.ConversionServiceFactoryBean) {
converters = [new CustomStringToArrayConverter()]
}
}
and
import org.springframework.core.convert.converter.Converter
import org.springframework.util.StringUtils
class CustomStringToArrayConverter implements Converter<String, String[]> {
#Override
public String[] convert(String source) {
return StringUtils.delimitedListToStringArray(source, ";");
}
}
but I couldn't get this to work either.
For now, I've come up with a work around. My Controller method has an extra line to set the troublesome field explicitly with:
commandObj.foo = params.list('foo') as String[]
I'm still open to suggestions on how to configure grails to not split on a comma...
I need to pass some arguments to a custom AbstractLifestyleManager derived type.
When I request an instance of a type from the container, I use the following overload:
T Resolve<T>(string key, object argumentsAsAnonymousType)
For example:
public IHttpController CreateController(HttpControllerContext controllerContext, string controllerName)
{
var controller = this.container.Resolve<IHttpController>(
controllerName,
new { requestProperties = controllerContext.Request.Properties });
// ...
}
Then, inside the custom AbstractLifestyleManager derived type, I can do this:
var messageProperties = (IDictionary<string, object>)
context.AdditionalArguments["requestProperties"];
Which returns the value that I have previsouly passed.
However, if I call base.Resolve(context, releasePolicy) the AdditionalArguments is null if the code enters the custom type recursively.
Is it possible to pass/flow the AdditionalArguments between the base.Resolve calls?
I am not quite sure how the flow is, when implementing a lifestyle manager, but it sounds like the problem that CreateContext AdditionalArguments aren't propagated to child context per default. See this other question.
If that is the case, you could try to change the default as described in the linked question by subclassing DefaultDependencyResolver.
I was wondering if I can capture the result of an action after the result returns and the JSP is rendered. I want to be able to take the entire result (generated HTML) and push it into memcached so I can bring it via Nginx with-out hitting the application server. Any ideas?
PS: I know I can run the interceptor after the action executes but before the result returns and the JSP is rendered, but not after the JSP is rendered.
I haven't found a way to do this inside of struts2, your best bet it to create a servlet Filter and have it modify the OutputStream.
http://onjava.com/pub/a/onjava/2003/11/19/filters.html
Hey I know its quite late now to answer you might have already found out the answer, however for others to benefit I am posting the answer.
One thing that is very similar to what you are doing is done by sitemesh filter.
Yes, filter comes before and after the Struts2 filter itself, so you can mess with the inputs and outputs easily.
But struts does evaluate JSP/freemarker/velocity and generate the final html which is passed to the user. JSP is a bit trickey because internally a servlet is called but check out org.apache.struts2.views.freemarker.FreemarkerResult class, you can see the actual html getting generated in template.process(model, writer);. This writer is actually ServletActionContext.getResponse().getWriter();
Now to get the html all you need to do is
ServletActionContext.getResponse().getWriter().toString() //This does not work out of box. To get the toString() to work you need to use a ResponseWrapper - which is the same method to get result html in Filters. See- Programming Customized Requests and Responses.
Listing to modify resulting html in struts 2. This is not tested, but it is extracted from my code I have written earlier for custom template engine. I will probably post full description in Custom template engine for struts2
public class DecoratorInterceptor implements Interceptor {
public String intercept(ActionInvocation invocation) throws Exception {
final ActionContext context = invocation.getInvocationContext ();
HttpServletResponse responseParent = (HttpServletResponse)
context.get(ServletActionContext.HTTP_RESPONSE);
CharResponseWrapper wrapper = new CharResponseWrapper(responseParent);
ServletActionContext.setResponse(wrapper);
//Actual Action called
String result = invocation.invoke();
String htmlReturned = wrapper.toString();
//play with htmlReturned ...
String modifiedhtml = pushintoMemCache(htmlReturned );
CharArrayWriter car = new CharArrayWriter();
car.write(modifiedhtml );
PrintWriter out = responseParent.getWriter();
out.write(car.toString());
out.flush();
}
#Override
public void destroy() {
// TODO Auto-generated method stub
}
#Override
public void init() {
// TODO Auto-generated method stub
}
}
Read this article - http://struts.apache.org/2.0.6/docs/interceptors.html
SUMMARY:When you request a resource
that maps to an "action", the
framework invokes the Action object.
But, before the Action is executed,
the invocation can be intercepted by
another object. After the Action
executes, the invocation could be
intercepted again. Unsurprisingly, we
call these objects "Interceptors."
Question: How do you determine if the view has been generated? Do you set a request header or an some sort of a flag to determine if the view has been generated?
You could try throwing a MemCachedException to indicate that it is time to load into a mem cache. Your interceptor code could read
try {
return invocation.invoke();
} catch (MemCachedException mce) {
// Your code to upload to MemCache.
} finally {
// blah blah clean up.
}
Within your interceptor's intercept() method, the ActionInvocation parameter has a getResult() method which returns null before Action execution (i. e. before you call invocation.invoke() in your intercept() method) and contains an implementation of Result afterwards. That object should give you some way to access the data you need, but how this is done probably depends on the class that is actually used.
See also my somewhat related question and the answer I posted after figuring it out.