Java Servlet Programming and application of the four

HttpServlet is inherited from Genericservlet, so it has genericservlet similar methods and objects, a package that we use with servlet programming, which supports methods such as post and get of HTTP.

Programming Idea: The following example, the operation result is the output simply returns the request line and the header information which the customer sends to the server, as well as some accessible HTTP information and so on.

Snoopservlet.java's source code is as follows:

Import java.io.IOException;
Import Java.io.PrintWriter;
Import java.util.Enumeration;
Import javax.servlet.*;
Import javax.servlet.http.*;
public class Snoopservlet extends HttpServlet {
public void doget (HttpServletRequest request, httpservletresponse response)
Throws Servletexception, IOException
{
PrintWriter out = Response.getwriter ();
Response.setcontenttype ("Text/plain");
Out.println ("Snoop Servlet");
Out.println ();
Out.println ("Servlet init parameters:");
Enumeration E = Getinitparameternames ();
while (E.hasmoreelements ()) {
String key = (string) e.nextelement ();
String value = Getinitparameter (key);
Out.println ("" + key + "=" + value);
}
Out.println ();
OUT.PRINTLN ("Context init parameters:");
ServletContext context = Getservletcontext ();
enumeration enum = Context.getinitparameternames ();
while (Enum.hasmoreelements ()) {
String key = (string) enum.nextelement ();
Object value = Context.getinitparameter (key);
Out.println ("" + key + "=" + value);
}
Out.println ();
OUT.PRINTLN ("Context attributes:");
enum = Context.getattributenames ();
while (Enum.hasmoreelements ()) {
String key = (string) enum.nextelement ();
Object value = Context.getattribute (key);
Out.println ("" + key + "=" + value);
}
Out.println ();
OUT.PRINTLN ("Request attributes:");
E = Request.getattributenames ();
while (E.hasmoreelements ()) {
String key = (string) e.nextelement ();
Object value = Request.getattribute (key);
Out.println ("" + key + "=" + value);
}
Out.println ();
Out.println ("Servlet Name:" + getservletname ());
Out.println ("Protocol:" + request.getprotocol ());
Out.println ("Scheme:" + request.getscheme ());
Out.println ("Server Name:" + request.getservername ());
Out.println ("Server Port:" + request.getserverport ());
Out.println ("Server Info:" + context.getserverinfo ());
Out.println ("Remote Addr:" + request.getremoteaddr ());
Out.println ("Remote Host:" + request.getremotehost ());
Out.println ("Character Encoding:" + request.getcharacterencoding ());
Out.println ("Content Length:" + request.getcontentlength ());
Out.println ("Content Type:" + request.getcontenttype ());
Out.println ("Locale:" + Request.getlocale ());
Out.println ("Default Response Buffer:" + response.getbuffersize ());
Out.println ();
Out.println ("Parameter names in this request:");
E = Request.getparameternames ();
while (E.hasmoreelements ()) {
String key = (string) e.nextelement ();
String[] values = request.getparametervalues (key);
Out.print ("" + key + "=");
for (int i = 0; i < values.length; i++) {
Out.print (Values[i] + "");
}
Out.println ();
}
Out.println ();
Out.println ("Headers in this request:");
E = Request.getheadernames ();
while (E.hasmoreelements ()) {
String key = (string) e.nextelement ();
String value = Request.getheader (key);
Out.println ("" + Key + ":" + value);
}
Out.println ();
Out.println ("Cookies in this request:");
cookie[] cookies = request.getcookies ();
if (cookies!= null) {
for (int i = 0; i < cookies.length; i++) {
Cookie cookie = cookies[i];
Out.println ("" + cookie.getname () + "=" + Cookie.getvalue ());
}
}
Out.println ();
Out.println ("Request is Secure:" + request.issecure ());
Out.println ("Auth Type:" + request.getauthtype ());
Out.println ("HTTP method:" + Request.getmethod ());
Out.println ("Remote User:" + request.getremoteuser ());
Out.println ("Request URI:" + Request.getrequesturi ());
OUT.PRINTLN ("Context Path:" + Request.getcontextpath ());
Out.println ("Servlet Path:" + Request.getservletpath ());
Out.println ("Path Info:" + request.getpathinfo ());
Out.println ("Path Trans:" + request.getpathtranslated ());
Out.println ("Query String:" + request.getquerystring ());
Out.println ();
HttpSession session = Request.getsession ();
OUT.PRINTLN ("Requested session Id:" +
Request.getrequestedsessionid ());
OUT.PRINTLN ("Current session Id:" + Session.getid ());
Out.println ("Session Created Time:" + session.getcreationtime ());
Out.println ("Session of Accessed time:" +session.getlastaccessedtime ());
Out.println ("Session Max Inactive Interval Seconds:" + session.getmaxinactiveinterval ());
Out.println ();
OUT.PRINTLN ("Session Values:");
Enumeration names = Session.getattributenames ();
while (Names.hasmoreelements ()) {
String name = (string) names.nextelement ();
Out.println ("" + name + "=" + session.getattribute (name));
}
}
}

Instructions for programming Tips: