No result defined for action and result input

问题

Here is my struts.xml

<package name="ajax" extends="json-default" >
    <action name="loadcity"  method="loadcity" class="roseindia.action.user.RegisterUser" >
        <result  type="json" />
    </action>
</package>

When I am calling loadcity.action I am getting following error

No result defined for action roseindia.action.user.RegisterUser and result input

Here is my action method:

public String loadcity()
{ 
    country=request.getParameter("country");

    cityList=  dao.loadcity(country);
    return ActionSupport.SUCCESS;
}

回答1:

First of all your srtuts.xml file is not completely defining the result type which should be render on the response of you action execution .result tag plays the role of a view in the Struts2 MVC framework. The action is responsible for executing the business logic. The next step after executing the business logic is to display the view using the tag. Here you can do one thing

<package name="ajax" extends="json-default" >
    <action name="loadcity"  method="loadcity" class="roseindia.action.user.RegisterUser" >
        <result name="input" type="json" />
    </action>
</package>

回答2:

The validation interceptor might return an INPUT result if you are doing POST request. Usually you are done with adding an "input" result to the action configuration, but as far as you return a "json" result, you can exclude this action from validation or check the result type or status code returned to the caller to handle the content.

回答3:

Your XML node result should have an attribute name with the value of "input" as this is what you are returning.

So your struts.xml should look:

<package name="ajax" extends="json-default" >
    <action name="loadcity"  method="loadcity" class="roseindia.action.user.RegisterUser" >
        <result name="input" type="json" />
    </action>
</package>

edited:

Another error could be: