HttpServletRequest和HttpServletResponse实例

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" ????xmlns="http://java.sun.com/xml/ns/javaee" ????xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" ????xsi:schemaLocation="http://java.sun.com/xml/ns/javaee ????http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> ?<servlet> ???<servlet-name>RequestDemo</servlet-name> ???<servlet-class>cn.test.request.RequestDemo</servlet-class> ?</servlet> ??<servlet> ???<servlet-name>ResponseDemo</servlet-name> ???<servlet-class>cn.test.response.ResponseDemo</servlet-class> ?</servlet> ?????<servlet-mapping> ???<servlet-name>RequestDemo</servlet-name> ???<url-pattern>/RequestDemo</url-pattern> ?</servlet-mapping> ?<servlet-mapping> ???<servlet-name>ResponseDemo</servlet-name> ???<url-pattern>/ResponseDemo</url-pattern> ?</servlet-mapping> </web-app>

 ?1 public class RequestDemo extends HttpServlet { ?2 ??3 ????public void doGet(HttpServletRequest request, HttpServletResponse response) ?4 ????????????throws ServletException, IOException { ?5 ????????/** ?6 ?????????* 设置参数查询的编码 ?7 ?????????* 该方法只能对请求实体内容的数据编码起作用。POST提交的数据在实体内容中，所以该方法对POST方法有效！ ?8 ?????????* GET方法的参数放在URI后面，所以对GET方式无效！！！ ?9 ?????????*/ 10 ????????request.setCharacterEncoding("utf-8"); 11 ?????????12 ?????????13 ????/* ???System.out.println("GET方式"); 14 ????????//接收GET方式提交的参数 15 ????????String value = request.getQueryString(); 16 ????????System.out.println(value);*/ 17 ?????????18 ?????????19 ????????/** 20 ?????????* 统一方便地获取请求参数的方法 21 ?????????*/ 22 ????????System.out.println(request.getMethod()+"方式"); 23 ????????//getParameter(name): 根据参数名得到参数值(只能获取一个值的参数) 24 ????????String name = request.getParameter("name"); 25 ?????????26 ????????/** 27 ?????????* 手动重新解码(iso-8859-1 字符串-> utf-8 字符串) 28 ?????????*/ 29 ????????/*if("GET".equals(request.getMethod())){ 30 ????????????name = new String(name.getBytes("iso-8859-1"),"utf-8"); 31 ????????}*/ 32 ?????????33 ????????String password = request.getParameter("password"); 34 ?????????35 ????????/*if("GET".equals(request.getMethod())){ 36 ????????????password = new String(password.getBytes("iso-8859-1"),"utf-8"); 37 ????????}*/ 38 ?????????39 ????????System.out.println(name+"="+password); 40 ?????????41 ????????System.out.println("============================="); 42 ????????Enumeration<String> enums = request.getParameterNames(); 43 ????????while( enums.hasMoreElements() ){ 44 ????????????String paramName = enums.nextElement(); 45 ?????????????46 ????????????//如果参数名是hobit，则调用getParameterValues 获取多个参数值 47 ????????????if("hobit".equals(paramName)){ 48 ????????????????/** 49 ?????????????????* getParameterValues(name): 根据参数名获取参数值（可以获取多个值的同名参数） 50 ?????????????????*/ 51 ????????????????System.out.println(paramName+":"); 52 ????????????????String[] hobits = request.getParameterValues("hobit"); 53 ????????????????for(String h: hobits){ 54 ????????????????/* ???if("GET".equals(request.getMethod())){ 55 ????????????????????????h = new String(h.getBytes("iso-8859-1"),"utf-8"); 56 ????????????????????}*/ 57 ????????????????????System.out.print(h+","); 58 ????????????????} 59 ????????????????System.out.println(); 60 ????????????????//如果不是hobit，则调用getParameter 61 ????????????}else{ 62 ????????????????String paramValue = request.getParameter(paramName); 63 ????????????????/* 64 ????????????????if("GET".equals(request.getMethod())){ 65 ????????????????????paramValue = new String(paramValue.getBytes("iso-8859-1"),"utf-8"); 66 ????????????????}*/ 67 ?????????????????68 ????????????????System.out.println(paramName+"="+paramValue); 69 ????????????} 70 ????????} 71 ????} 72 ????public void doPost(HttpServletRequest request, HttpServletResponse response) 73 ????????????throws ServletException, IOException { 74 ????????/*System.out.println("POST方式"); 75 ????????InputStream in = request.getInputStream(); 76 ????????byte[] buf = new byte[1024]; 77 ????????int len = 0; 78 ????????while( ?(len=in.read(buf))!=-1 ){ 79 ????????????System.out.println(new String(buf,0,len)); 80 ????????}*/ 81 ?????????82 ????????/** 83 ?????????* 统一方便地获取请求参数的方法 84 ?????????*/ 85 ????????/*System.out.println("POST方式"); 86 ????????//根据参数名得到参数值 87 ????????String name = request.getParameter("name"); 88 ????????String password = request.getParameter("password"); 89 ????????System.out.println(name+"="+password); 90 ?????????91 ????????System.out.println("============================="); 92 ????????Enumeration<String> enums = request.getParameterNames(); 93 ????????while( enums.hasMoreElements() ){ 94 ????????????String paramName = enums.nextElement(); 95 ????????????String paramValue = request.getParameter(paramName); 96 ????????????System.out.println(paramName+"="+paramValue); 97 ????????}*/ 98 ?????????99 ????????//一定调用doGet方式100 ????????this.doGet(request, response);101 ????}102 103 }

public class ResponseDemo extends HttpServlet { ???/** ????* 1)tomcat服务器把请求信息封装到HttpServletRequest对象，且把响应信息封装到HttpServletResponse ????* 2）tomcat服务器调用doGet方法，传入request，和response对象 ????*/ ???public void doGet(HttpServletRequest request, HttpServletResponse response) ???????????throws ServletException, IOException { ???????/** ????????* 3）通过response对象改变响应信息 ????????*/ ???????/** ????????* 3.1 响应行 ????????*/ ???????//response.setStatus(404);//修改状态码 ???????//response.sendError(404); // 发送404的状态码+404的错误页面 ???????????????????????????????/** ????????* 3.2 响应头 ????????*/ ???????response.setHeader("server", "JBoss"); ???????????????????????/** ????????* 3.3 实体内容(浏览器直接能够看到的内容就是实体内容) ????????*/// ???????response.getWriter().write("01.hello world"); //字符内容。 ???????response.getOutputStream().write("02.hello world".getBytes());//字节内容 ????????????} ???????/** ????* 4)tomcat服务器把response对象的内容转换成响应格式内容，再发送给浏览器解析。 ????*/}

 1 public class ResponseDemo2 extends HttpServlet { 2 ?3 ????public void doGet(HttpServletRequest request, HttpServletResponse response) 4 ????????????throws ServletException, IOException { 5 ????????/** 6 ?????????* 需求： 跳转到adv.html 7 ?????????* 使用请求重定向： 发送一个302状态码+location的响应头 8 ?????????*/ 9 ????????/*response.setStatus(302);//发送一个302状态码10 ????????response.setHeader("location", "/day09/adv.html"); //location的响应头11 */ ???????12 ????????13 ????????//请求重定向简化写法14 ????????response.sendRedirect("/day09/adv.html");15 ????????16 ????????17 ????}18 19 }

 1 public class ResponseDemo extends HttpServlet { 2 ?3 ????public void doGet(HttpServletRequest request, HttpServletResponse response) 4 ????????????throws ServletException, IOException { 5 ????????/** 6 ?????????* 定时刷新 7 ?????????* 原理：浏览器认识refresh头，得到refresh头之后重新请求当前资源 8 ?????????*/ 9 ????????//response.setHeader("refresh", "1"); //每隔1秒刷新次页面10 ????????11 ????????/**12 ?????????* 隔n秒之后跳转另外的资源13 ?????????*/14 ????????response.setHeader("refresh", "3;url=/day09/adv.html");//隔3秒之后跳转到adv.html15 ????}16 17 }