HttpServletRequest学习
package cn.request;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.InvocationTargetException;
import java.util.Enumeration;
import java.util.Map;
import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.commons.beanutils.BeanUtils;
import cn.response.com.ResDemo2;
public class ReqDemo1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
test8(request,response);
}
//利用requset 设置请求头 referer 放盗链
private void test8(HttpServletRequest request, HttpServletResponse response) throws IOException {
String data = "aaaa";
String referer = request.getHeader("referer");
if (referer == null || !referer.startsWith("http://localhost")) {
response.sendRedirect("/Test/index.jsp"); // 如果不是从我的网站来请求的资源，那就跳到主页， 然胡再在主页提供连接再回来请求
} else {
response.getWriter().print(data);
}
}
//跳转之前数据不能写给客户端 java.lang.IllegalStateException: Cannot forward after response has been committed
//forward会清空response中的数据
//请求转发特点： 1： 客户端只发送一次请求，而服务端会产生多个资源的调用 2：客户机地址栏没有变化
private void test7(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
String data = "aa";
PrintWriter pw = response.getWriter();
pw.write(data);
pw.close();
request.getRequestDispatcher("/Test/index.jsp").forward(request, response);
}
//request的请求转发 实现MVC框架的设计思想
private void test6(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String data = "aaa";
HttpSession session = request.getSession();
session.setAttribute("data", data);
request.getRequestDispatcher("index.jsp").forward(request, response);
}
//解决中文乱码问题
private void test5(HttpServletRequest request) throws UnsupportedEncodingException {
/*request.setCharacterEncoding("UTF-8"); //只对post提交有效
String name = request.getParameter("name");
System.out.println("name = " + name);*/
//手工解决都get post 都可以..
String name = request.getParameter("name");
String myName = new String(name.getBytes("ISO-8859-1"),"UTF-8");
System.out.println("myName = " + myName);
}
//利用request收集用户提交的数据
private void test4(HttpServletRequest request) {
String username = request.getParameter("username");
System.out.println("username = " + username);
String password = request.getParameter("password");
System.out.println("password = " + password);
String gender = request.getParameter("gender");
System.out.println("gender = " + gender);
String address = request.getParameter("address");
System.out.println("address = " + address);
String[] likes = request.getParameterValues("likes");
for (int i = 0; likes != null && i < likes.length; ++i) {
System.out.println("likes :" + likes[i]);
}
String des = request.getParameter("des");
System.out.println("des = " + des);
String id = request.getParameter("id");
System.out.println("id = " + id);
}
//获得请求数据
private void test3(HttpServletRequest request) {
String name1 = request.getParameter("name");
Enumeration<String> e = request.getParameterNames();
while (e.hasMoreElements()) {
String name = e.nextElement();
String value = request.getParameter(name);
System.out.println("name = " + name + " value = " + value);
}
String[] v = request.getParameterValues("name");
for (int i = 0; v != null && i < v.length; ++i) {
System.out.println(v[i]);
}
Map<String, String[]> entity = request.getParameterMap();
User u = new User();
//这样可以利用BeanUtils 简单操作
try {
BeanUtils.populate(u, entity);
} catch (IllegalAccessException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (InvocationTargetException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
//获取请求头
private void test2(HttpServletRequest request) {
String headValue = request.getHeader("Accept-Encoding");
System.out.println(headValue);
Enumeration<String> e = request.getHeaders("Accept-Encoding");
while (e.hasMoreElements()) {
String value = e.nextElement();
System.out.println(value);
}
e = request.getHeaderNames();
while (e.hasMoreElements()) {
String name = e.nextElement();
String value = request.getHeader(name);
System.out.println("name = " + name + " value = " + value);
}
}
//获得用户请求的URI和URL 可以实现用户权限的控制， 统计某个web资源被访问的次数
private void test1(HttpServletRequest request) {
System.out.println("URI : " + request.getRequestURI());
System.out.println("URL : " + request.getRequestURL());
http://localhost:8080/Test/ReqDemo1?name=gbx
System.out.println("查询参数: " + request.getQueryString());
System.out.println("IP :" + request.getRemoteAddr());
System.out.println("Port :" + request.getRemotePort());
System.out.println("Host :" + request.getRemoteHost());
System.out.println("客户机请求方式 ：" + request.getMethod());
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
class User{
}
这里是测试request手机数据时的jsp:
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<meta http-equiv="content-tyoe" content="text/html; charset=UTF-8">
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form action="/Test/ReqDemo1" method="post">
用户名： <input type="text" name="username"> <br/>
密码： <input type="password" name="password"> <br/>
性别 : <input type="radio" name="gender" value="男"><br/>
<input type="radio" name="gender" value="女"><br/>
住址： <select name="address">
<option value="bj">北京</option>
<option value="sd">山东</option>
</select> <br/>
爱好： <input type="checkbox" name="likes" value="bas">篮球
<input type="checkbox" name="likes" value="sing">唱歌
<input type="checkbox" name="likes" value="dance">跳舞
<br/>
<input type="hidden" name = "id" value="123"> <br/>
简介：<textarea rows="6" cols="60" name="des"></textarea><br/>
照片: <input type="file" name="image"><br/>
<input type="submit" value="提交">
</form>
</body>
</html>
利用Http头的referer 实现图片的防盗链， 不是本网张的不给显示
jsp
<body> <img alt="" src="/Test/ImgServlet?filename=1.jpg"> </body>
Servlet
package cn.request;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ImgServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String referer = request.getParameter("referer");
//如果非法就不给资源
if (referer == null || !referer.startsWith("http://localhost")) {
return ;
} else { //合法
String filename = request.getParameter("filename");
System.out.println(referer + " " + filename);
String path = this.getServletContext().getRealPath("/download/" + filename);
System.out.println("path : " + path);
InputStream in = new FileInputStream(path);
OutputStream out = response.getOutputStream();
int len = 0;
byte[] buf = new byte[1024];
while ((len = in.read(buf)) > 0){
out.write(buf, 0, len);
}
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
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