jsp源码实例2（获取表单参数）

package coreservlets;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;

/** Shows all the parameters sent to the servlet via either
* GET or POST. Specially marks parameters that have
* no values or multiple values.
* <P>
* Taken from Core Servlets and JavaServer Pages
* from Prentice Hall and Sun Microsystems Press,
* http://www.coreservlets.com/.
* © 2000 Marty Hall; may be freely used or adapted.
*/

public class ShowParameters extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String title = "Reading All Request Parameters";
out.println(ServletUtilities.headWithTitle(title) +
"<BODY BGCOLOR=\"#FDF5E6\">\n" +
"<H1 ALIGN=CENTER>" + title + "</H1>\n" +
"<TABLE BORDER=1 ALIGN=CENTER>\n" +
"<TR BGCOLOR=\"#FFAD00\">\n" +
"<TH>Parameter Name<TH>Parameter Value(s)");
Enumeration paramNames = request.getParameterNames();
while(paramNames.hasMoreElements()) {
String paramName = (String)paramNames.nextElement();
out.print("<TR><TD>" + paramName + "\n<TD>");
String[] paramValues =
request.getParameterValues(paramName);
if (paramValues.length == 1) {
String paramValue = paramValues[0];
if (paramValue.length() == 0)
out.println("<I>No Value</I>");
else
out.println(paramValue);
} else {
out.println("<UL>");
for(int i=0; i<paramValues.length; i++) {
out.println("<LI>" + paramValues);
}
out.println("</UL>");
}
}
out.println("</TABLE>\n</BODY></HTML>");
}

public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}