HttpServletRequest获取请求

public class DemoServlet01 extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//1.获取HTTP请求消息中的请求方式
		System.out.println("请求方式：" + request.getMethod());
		//2.获取请求行中资源名称部分
		System.out.println("资源部分= url:" + request.getRequestURL());
		//3.获取请求行中的参数部分
		System.out.println("请求行中的参数：" + request.getQueryString());
		//4.获取请求行的协议和版本
		System.out.println("请求的协议个版本："+request.getProtocol());
		//5.获取WEB应用程序的路径
		System.out.println("获取应用程序的路径:"+ request.getContextPath());	
		//6.获取Servlet的名称或Servlet所映射的路径 
		System.out.println("获取Servlet的名称:"+request.getServerName());
		System.out.println( "路径：" + request.getServletPath());
		//7.获取请求客户端的IP地址
		System.out.println("获取客户端的IP地址：" + request.getRemoteAddr());		
		//8.获取请求客户端的完整主机名
		System.out.println("获取请求客户端的完整主机名:" + request.getRemoteHost());		
		//9.获取请求客户端网络连接的端口号
		System.out.println("客户端网络连接的端口号:" + request.getRemotePort());		
		//10.获取Web服务器上接收当前请求网络连接的IP地址
		System.out.println("接收当前请求网络连接的IP地址:" + request.getLocalAddr());		
		//11.获取Web服务器上接收当前网络连接IP所对应的主机名
		System.out.println("接收当前网络连接IP所对应的主机名:"+request.getLocalName());		
		//12.获取Web服务器上接收当前网络连接的端口号		
		System.out.println("获取Web服务器上接收当前网络连接的端口号：" + request.getLocalPort());
		//13.获取当前请求所指向的主机名		
		System.out.println("获取当前请求所指向的主机名:" + request.getServerName());
		//14.获取当前请求所连接的服务器端口号
		System.out.println("获取当前请求所连接的服务器端口号:" + request.getServerPort());		
		//15.获取请求的协议名
		System.out.println("获取请求的协议名：" + request.getScheme());		
		//16.获取客户端发出请求时的完整URL
		System.out.println("获取客户端发出请求时的完整URL:" + request.getRequestURL());
	}

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

public class DemoServlet02 extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setCharacterEncoding("text/html;charset=utf-8");
		//1.获取一个指定头字段值
		System.out.println(request.getHeader("host"));
		//2.获取指定头字段的多个值
		Enumeration<String> names = request.getHeaderNames();
		while(names.hasMoreElements()){
			System.out.println(names.nextElement());
		}
		//3. 获取请求头中所有的请求头字段的名称
		Enumeration<String> list = request.getHeaderNames();//所有的键
		while(list.hasMoreElements()){
			String name = list.nextElement();
			String header = request.getHeader(name);
			response.getWriter().println(name + " === " + header + "<br/>");
		}
		//4.获取指定名称参数
		System.out.println("获取指定名称参数"+request.getParameter("username"));
		//5.获取所有参数名
		Enumeration<String> parameterNames = request.getParameterNames();
		//6.获取多个参数值
		System.out.println(Arrays.toString(request.getParameterValues("aihao")));
		//7.用于将请求消息中的所有参数名和值装入进一个Map对象中返回
		Map<String, String[]> map = request.getParameterMap();
		for (String key : map.keySet()) {
			System.out.println(key + "--" + map.get(key));
		}
	}
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request, response);
	}
}