request.getQueryString()和request.getPathTranslated()结果为什么是NULL
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out
.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println(" <BODY>");
out.print(this.getClass());
out.println(", using the POST method");
// 获取参数名
out.print("<TH>Parameter Name<TH>Parameter Value(s)");
Enumeration parameterNames=request.getParameterNames();
while(parameterNames.hasMoreElements()){
String paraName=(String)parameterNames.nextElement();
String pa=(String)request.getServletPath();//返回servlet的路径
String pa1=(String)request.getPathTranslated();//映射到服务器的实际路径的路径信息.
Cookie [] co=request.getCookies();
for(int i=0;i<co.length;i++){
out.println(co[i]);
}
String yuanshishuju=(String)request.getQueryString();
out.print("<br>"+paraName);
String[]parameterValues=request.getParameterValues(paraName);
if(parameterValues.length==1){
String paramValue=parameterValues[0];
if(parameterValues.length==0)
out.print("<I>NO VALUe</I>");
else
out.println(paramValue);
out.println("pa1:");
out.println("yuanshishuju");
out.println(yuanshishuju);
out.println(pa1);
out.println("<br>");
out.println("show_servletpathPa");
out.print(pa);
}else {
out.println("<UL>");
for(int i=0;i<parameterValues.length;i++){
out.println("<LI>"+parameterValues[i]);
}
out.println("</UL>");
}
}
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
页面上显示的结果:
class ShowParameters, using the POST method Parameter NameParameter Value(s)javax.servlet.http.Cookie@1742dfe
check
on
on
on
on
javax.servlet.http.Cookie@1742dfe
load pa1: yuanshishuju null null
show_servletpathPa /ShowParametersjavax.servlet.http.Cookie@1742dfe
aa pa1: yuanshishuju null null
show_servletpathPa /ShowParameters