Print out a variable in a Java servlet using output stream

Question

public class DemoServlet extends HttpServlet {

    public void service(HttpServletRequest req, HttpServletResponse resp)
        throws IOException, ServletException {

        //prints out my string
        resp.getOutputStream().write("Hello from servlet\n".getBytes());

        String variable ="VAR";
        //trying to print out variable by this way but doesn't work
        resp.getOutputStream().write("%s\n".getBytes(),variable);
        //doesn't work this way either
        resp.getOutputStream().write("variable is:"+ variable +"something else\n".getBytes());
    }
}

First, I was using PageWriter out= resp.getWriter(); but then I switched to ServletOutputStream because I wanted to print images. Every thing else is OK but:

public void makedbconnection() {
    try {
        Class.forName("com.mysql.jdbc.Driver").newInstance();
        Dbcon = DriverManager.getConnection("jdbc:mysql://localhost/test");
    } catch(Exception idc) {
       //ON THIS LINE, out is ServletOutputStream.
       idc.printStackTrace(out);
    }
    //System.out.println("connection made");
}

Please, next time explain your problem with text, not only code. Also, when you are satisfied with an answer, accept it. Thanks! — Alba Mendez
– Alba Mendez, Commented Apr 21, 2011 at 16:34

blackpanther · Accepted Answer · 2014-04-09 14:48:46Z

5

Obviously you can use ServletOutputStream#print but you could use PrintWriter as well.

resp.getWriter().print(yourvariable)

edited Apr 9, 2014 at 14:48

blackpanther

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answered Apr 21, 2011 at 15:31

Nishant

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Comments

Ernest Friedman-Hill · Accepted Answer · 2011-04-21 15:26:40Z

4

out is a ServletOutputStream. It has a rich set of overloaded print() methods. Just use

out.print(variable);

answered Apr 21, 2011 at 15:26

Ernest Friedman-Hill

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Comments

Alba Mendez · Accepted Answer · 2011-04-21 16:46:32Z

0

ServletOutputStream has a large set of print(...) methods. When printing text, it's better to use them instead of write(...) ones.

Also, note that you can use print or write multiple times:

out.print("Hello, the variable is ");
out.print(variable);
out.println(". Something else?");

Notice that, instead of adding a \n in the end of the string, it's better to use println.

answered Apr 21, 2011 at 16:46

Alba Mendez

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