request细节一----->通过request获取ip
/**
* Servlet request常用方法
*/
@WebServlet("/RequestDemo1")
public class RequestDemo1 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//页面访问次数，拦截访问
System.out.println(request.getRequestURI());//很常见
System.out.println(request.getRequestURL());
System.out.println(request.getQueryString());//得到查询信息也就是http://www.snowing.com?name=1
//得到name=1
System.out.println(request.getRemoteAddr());//得到访问者ip地址
System.out.println(request.getRemoteHost());//得到访问者主机名---》如果没在dns上注册就打印主机名
System.out.println(request.getRemotePort());//得到访问者端口(随机的)
System.out.println(request.getLocalAddr());//返回web服务器的主机地址
System.out.println(request.getLocalName());//返回web服务器的主机名---》如果没在dns上注册就打印主机名
System.out.println(request.getMethod());//得到客户机请求方式
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
结果：访问：http://localhost:8082/day05/RequestDemo1?name=1
request细节二----->通过request获取头信息
request细节三----->通过request获取请求头数据
request细节四----->通过request控制编码问题
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// request.setCharacterEncoding("UTF-8");//只有post生效
String username=new String(request.getParameter("username").getBytes("iso8859-1"),"UTF-8");
//反向查找，get／post都可以
//URLEncoder.encode(username, "UTF-8");
System.out.println(username);
}
<meta charset="UTF-8">
另一种处理方式，在uri里带参数的情况，可以在tomcat server.xml里配置
post和get都通用的乱码配置情况：
servlet里配置：
server.xml:
request细节四----->MVC模式（model=javabean view=jsp controller=servlet）
jsp：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
${data}
<%
String data=(String) request.getAttribute("data");
out.write(data);
%>
</body>
</html>
servlet：
/**
* 请求转发，以及使用request域对象把数据带给转发资源
*/
@WebServlet("/RequestDemo3")
public class RequestDemo3 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String data="aaaa";
request.setAttribute("data", data);
request.getRequestDispatcher("/1.jsp").forward(request, response);//把数据转发给jsp，并显示
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
转发不能在response关闭后转发，所以一定记得，return！！！
//forward会清空response中的数据
页头和页脚总一样就用这种方式：
注意：head.jsp和foot.jsp要这样
