Servlet: Handling many optional parameters

Question

Just wondering if there is a more elegant or standard way to handle the optional parameters or if you have to check if every one is null. I have 10+ optional parameters so it is getting somewhat ugly.

Ideally I would like something like the bash command: getopts.

public class MapImageServlet extends HttpServlet {
    ... constructor and other methods ...
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        // OPTIONAL PARAMETERS
        if(request.getParameter("boarderSize") != null){
            double boarderSize = Double.valueOf(request.getParameter("boarderSize");
        }

        if(request.getParameter("boarderThickness") != null){
            double boarderThickness = Double.valueOf(request.getParameter("boarderThickness");
        }

        if(request.getParameter("boarderColor") != null){
            double boarderColor = Double.valueOf(request.getParameter("boarderColor");
        }
        ... do stuff with the parameters ...
    }
    ... other methods ...
}

Don't declare the variable inside your if statement, it won't be available to other scopes. — Marcelo
– Marcelo, Commented Jun 13, 2011 at 20:14
@Marcelo, sorry about that. Normally would not do that, haha. — sixtyfootersdude
– sixtyfootersdude, Commented Jun 13, 2011 at 20:25

Community · Accepted Answer · 2013-12-06 09:03:02Z

2

Write a utility like this

public class MapImageServlet extends HttpServlet {
//... constructor and other methods ...
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    // OPTIONAL PARAMETERS
     boarderSize = ParamUtil.getDoubleValue(request,"boarderSize", defaultValue);

     boarderThickness = ParamUtil.getDoubleValue(request, "boarderThickness", defaultValue);

     boarderColor = ParamUtil.getDoubleValue(request,"boarderColor" , defaultValue);
     //... do stuff with the parameters ...
}

}
public class ParamUtil
{
public static double getDoubleValue(ServletRequest request, String paramName, double defaultValue)
{
     if(request.getParameter(paramName) != null){
        return Double.valueOf(request.getParameter(paramName));
    } else{
        return defaultValue;
    }
}
}

edited Dec 6, 2013 at 9:03

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answered Jun 14, 2011 at 5:51

Ramesh PVK

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1 Comment

sixtyfootersdude Over a year ago

I thought that there would already be something made like this already in the servlet but I guess that it is easy to make my own.

Tomasz Nurkiewicz · Accepted Answer · 2011-06-13 20:23:18Z

2

Aren't you looking for: ServletRequest#getParameterMap?

answered Jun 13, 2011 at 20:23

Tomasz Nurkiewicz

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1 Comment

DwB Over a year ago

Incase you are stuck on an old WAS or something, getParameterMap is in JEE 5.0 as well.

Kal · Accepted Answer · 2011-06-13 21:00:05Z

0

Generally, I have used Apache beanutils to pull information from request parameter map. BeanUtils provides a nice interface that hides all this information from you ...

MyJavaBean mjb = new MyJavaBean();
BeanUtils.copyProperties(mjb, request.getParameterMap());

.... 
// do stuff with mjb properties
logger.debug(mjb.getBorderThickness());
logger.debug(mjb.getBorderSize());
// etc

A little extra work setting up the javabean but easy to use going forward.

answered Jun 13, 2011 at 21:00

Kal

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Comments

Sid · Accepted Answer · 2011-06-13 21:05:03Z

0

If you are developing this from scratch I suggest you go with a framework like Spring MVC or Struts. These frameworks capture the input and provide you with a ready to use bean with all the form data.

answered Jun 13, 2011 at 21:05

Sid

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