HttpServlet 是从GenericServlet 继承而来,因此它具有GenericServlet 类似的方法和对象,是我们使用Servlet
编程经常用到的包,它支持HTTP 的post 和 get 等方法。
编程思路:下面的例子,运行结果是输出简单地返回客户发送给服务器的请求行和头部信息,以及一些可访问的HTTP 信息等。
SnoopServlet.java 的源代码如下:
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.ge |