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Thread: User Validation in JSP

  1. #1
    Join Date
    Sep 2005
    Posts
    38

    User Validation in JSP

    Hi

    I did custom tag like this.

    FirstCustomPage.jsp:---

    <%@ taglib uri="/customtable1" prefix="customtable" %>
    <form name="form1" method="post" action="DemoServlet" >
    <table border = 2>
    <tr>
    <customtable:customtd name="UserId" value="" />

    </tr>
    <tr>
    <customtable:customtd name="UserName" value="" />
    </tr>
    <tr>
    <td>
    <input type = submit value = Submit>
    </td>
    </tr>
    </table>
    </form>

    CustomTagDemo.java:-

    public class CustomTagDemoextends TagSupport{

    private String name;
    private String value ;

    public int doStartTag() throws JspException {

    JspWriter out = pageContext.getOut();
    StringBuffer sb = new StringBuffer();
    sb.append("<td><b> " + name + "<//b></td><td><input type = text name ="+name+"");

    String valueObject = pageContext.getRequest().getParameter(name);

    if(valueObject != null)
    {
    System.out.println("inside valueObject" + valueObject);
    sb.append(" value=\"" + valueObject + "\"");
    }
    sb.append(" /></td>");

    if(valueObject != null && valueObject.equals(""))
    {
    sb.append("<td><font color=red>Please Enter the value</font></td>");
    }

    return SKIP_BODY;
    }

    public void setValue(String _value)
    {
    value = _value;
    }
    public String getValue() {
    return value;
    }

    public String getName() {
    return name;
    }

    public void setName(String name) {
    this.name = name;
    }


    }

    DemoServlet.java:--

    public class DemoServlet extends HttpServlet {


    protected void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {


    Enumeration enum = req.getParameterNames();

    while(enum.hasMoreElements())
    {
    String value = req.getParameter(enum.nextElement().toString());
    if(value.equals("")){
    RequestDispatcher dispatcher = req.getRequestDispatcher("/FirstCustomPage.jsp");
    if (dispatcher != null)
    dispatcher.forward(req, res);
    }

    }
    }

    Its working fine.But I can't do checking in servlet.After checking only then control should go to Servlet.So I have to remove that code from servlet.I have to check in JSP Page only(cannot use javascript). I don't know how to do that.Can u plz tell me how to do it without using JavaScript.Is there any other way to validate textbox.

  2. #2
    Join Date
    Jul 2004
    Location
    West Coast, Canada
    Posts
    665
    Can't you just use request.getParameter("fieldName"); and validate from there?

    "Everything in a web browser."

  3. #3
    Join Date
    Sep 2005
    Posts
    38
    Hi
    I gave like this....


    <%@ taglib uri="/customtable1" prefix="customtable" %>

    <% int flag = 0; %>
    <center>
    <form name="form1" method="post" bgcolor =cccccc >
    <body bgcolor =cccccc >
    <h3>Users Details</h3>
    <br><br><br>

    <table border = 2>
    <tr>
    <customtable:customtd name="UserId" value="" />
    </tr>
    <tr>
    <customtable:customtd name="UserName" value="" />
    </tr>
    <tr>
    <td></td>
    <td>
    <input type = submit value = Submit>
    </td>
    </tr>
    </table>

    <%

    if((request.getParameter("UserId") == null) || (request.getParameter("UserName") == null))
    {
    flag = 0;
    }
    else if((request.getParameter("UserId").equals("")) || (request.getParameter("UserName").equals("")))
    {
    flag=0;
    }

    else
    {
    flag = 1;
    }
    if(flag == 1)
    { %>

    <jsp:forward page="DemoServlet" />

    <% } %>
    </body>
    </form>
    </center>
    I did like this.It is working.But Suppose I have 10 fields.It is not possible to write all the fields & validate..Is there any easy way to do it. & one more thing suppose If I gave one space in textbox.It won't show any error message.I tried to give trim() . It showing error.

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