How to access url parameters in Action classes Str

问题:

I'm new to Java EE and Struts2. I need to know if I'm doing it wrong or not.

I've got a link like this : http://localhost:8080/myProject/deleteUser?idUser=42

All I want is to get the idUser value.

Here is what I use to get the parameter value in my action class :

HttpServletRequest request = (HttpServletRequest) ActionContext.getContext()
                                  .get(ServletActionContext.HTTP_REQUEST);
System.out.println(request.getParameter("idUser"));

回答1:

S2 provides a clean way to fetch the request parameters in you action class all you need to follow these simple rules.

1. Create a property with same name as request parameter name.
2. create getter and setters for this property or make property public (for S2.1+)

S2 will check the request parameter and will look for matching property in your action class and will inject the value in respected property.

in your case all you need to do

public class MyAction extends ActionSupport{

 private String idUser;
 getter and setters   

}

So in this case S2 will find the idUser property in your action class and its build in interceptor will inject the value in the idUser property

回答2:

Well, I'm not a Struts expert, but what I do in my Struts 2.2 project (and it works ok) is:

String paramValue = ServletActionContext.getRequest().getParameter("paramName");

Here paramName would be "idUser".

回答3:

Try this:

ActionContext context = ActionContext.getContext();
Map<String, Object> params = context.getParameters();
String userId = findParam("idUser", params);

public String findParam(String key, Map<String, Object> params) {
  Object obj = params.get(key);
  if(obj != null) {
    String[] values = (String[])obj;
    return values.length > 0 ? values[0] : null;
  } 
  return null;
}

回答4:

public class MyAction extends ActionSupport {
    HttpServletRequest request;
    String idUser = request.getParameter("idUser");
    System.out.println(idUser);

}

Try this!