详解JSP 中request与response的用法

/**  * 获取HTTP请求头 　*　　　String getHeader(String name)，适用于单值头 　*　　　int getIntHeader(String name)，适用于单值int类型的请求头 　*　　　long getDateHeader(String name)，适用于单值毫秒类型的请求头 　*　　  Enumeration<String> getHeaders(String name)，适用于多值请求头  *  *  */ public class CServlet extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {      String ip = request.getRemoteAddr();//获取IP地址     String method = request.getMethod();//获取请求方式     System.out.println(ip);     System.out.println(method);     getLiuLanQi(request);     protectMethod(request, response);   } //防盗链   public void protectMethod(HttpServletRequest request,       HttpServletResponse response) {     String url = request.getHeader("referer");     System.out.println(url);     if(url != null && url.equalsIgnoreCase("http://localhost:8080/day10/MyHtml.html") ) {       System.out.println("hi");     }     else {       response.setStatus(302);       response.setHeader("Location","/day10/MyHtml.html");       System.out.println("重定向");     }   } //判断浏览器的类型   public void getLiuLanQi(HttpServletRequest request) {     String user = request.getHeader("User-Agent");     if(user != null) {       String userNoC = user.toLowerCase();       if(userNoC.contains("chrome")) {         System.out.println("浏览器类型：谷歌" );       }       else if(userNoC.contains("firefox/")) {         System.out.println("浏览器类型：火狐");       }       else {         System.out.println("浏览器类型：IE");       }     }     else {       System.out.println("null");     }   } } 

/**  * 获取请求URL   http://localhost:8080/day10_2/AServlet?username=xxx&password=yyy 　　　　> String getScheme()：获取协议，http 　　　　> String getServerName()：获取服务器名，localhost 　　　　> String getServerPort()：获取服务器端口，8080 　　　　> *****String getContextPath()：获取项目名，/day10_2 　　　　> String getServletPath()：获取Servlet路径，/AServlet 　　　　> String getQueryString()：获取参数部分，即问号后面的部分。username=xxx&password=yyy 　　　　> String getRequestURI()：获取请求URI，等于项目名+Servlet路径。/day10_2/AServlet 　　　　> String getRequestURL()：获取请求URL，等于不包含参数的整个请求路径。http://localhost:8080/day10_2/AServlet  *  *  */ public class DServlet extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     System.out.println(request.getScheme());     System.out.println(request.getServerName());     System.out.println(request.getServerPort());     System.out.println(request.getContextPath());     System.out.println(request.getServletPath());     System.out.println(request.getQueryString());     System.out.println(request.getRequestURI());     System.out.println(request.getRequestURL());   }  } 

/**  *  * 请求参数：有一个参数一个值的，还有一个参数多个值！ 　　　　> *****String getParameter(String name)：获取指定名称的请求参数值，适用于单值请求参数 　　　　> String[] getParameterValues(String name)：获取指定名称的请求参数值，适用于多值请求参数 　　　　> Enumeration<String> getParameterNames()：获取所有请求参数名称 　　　　> *****Map<String,String[]> getParameterMap()：获取所有请求参数，其中key为参数名，value为参数值。  *  */ public class EServlet extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     doPost(request,response);   }    public void doPost(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     request.setCharacterEncoding("utf-8");//调用他来解决乱码问题的，不会的可以看我写的解决乱码的那一篇     String name = request.getParameter("name");     String password = request.getParameter("password");     String[] aihao = request.getParameterValues("aihao");     response.setHeader("content-type", "text/html;charset=utf-8");     PrintWriter pw = response.getWriter();     pw.println("name:" + name + "<br/>");     pw.println("password:" + password + "<br/>");     pw.print("aihao");     for (int i = 0; i < aihao.length; i++) {       switch (i) {       case 1:         pw.print("吃饭");         break;       case 2:         pw.print("睡觉");         break;       case 3:         pw.print("打豆豆");         break;        default:                  break;       }     }     pw.close();   }  } 

<!-- 用于发送请求的html --> <html>  <head>   <title>denglu.html</title>   <meta http-equiv="content-type" content="text/html; charset=UTF-8">  </head>    <body>   <form action="/day10/EServlet" method="post"><!-- 通过post方法提交 -->     姓名:<input type="text" name="name"/><br/>     密码:<input type="password" name="password"><br/>     爱好：<input type="checkbox" name="aihao" value="1"/>吃饭     <input type="checkbox" name="aihao" value="2"/>睡觉     <input type="checkbox" name="aihao" value="3"/>打豆豆     <input type="submit" value="提交">   </form>  </body> </html> 

/**  *  ** request域 　　　　Servlet中三大域对象：request、session、application，都有如下三个方法： 　　　　> void setAttribute(String name, Object value) 　　　　> Object getAttribute(String name)    > void removeAttribute(String name); 　　　　> 同一请求范围内使用request.setAttribute()、request.getAttribute()来传值！前一个Servlet调用setAttribute()保存值，后一个Servlet调用getAttribute()获取值。   *  */ public class FServlet extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     request.setAttribute("name","weijinhao");     request.setAttribute("password", "123");     RequestDispatcher rd = request.getRequestDispatcher("/GServlet");     rd.forward(request, response);   }  } 

public class GServlet extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     String name = (String)request.getAttribute("name");     String password = (String)request.getAttribute("password");     response.setHeader("content-type", "text/html;charset=utf-8");     PrintWriter pw = response.getWriter();     pw.println("name:" + name + "<br/>");     pw.println("password:" + password + "<br/>");     pw.close();   }  } 

/**    * response的正文    * 1,字符流    * 2,字节流    */   public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     //String n = "hello javaweb";     //byte[] b = n.getBytes();     //字节流的使用     /*ServletOutputStream outputStream = response.getOutputStream();     outputStream.write(b);     outputStream.close();*/               //字符流的使用     /*PrintWriter p = response.getWriter();     p.write(n);     p.close();*/          //commoms工具包的使用     FileInputStream fileInputStream = new FileInputStream("C:/Users/74087/Desktop/6226354_994604.jpg");     byte[] b = IOUtils.toByteArray(fileInputStream);     ServletOutputStream outputStream = response.getOutputStream();     outputStream.write(b);     outputStream.close();   }  } 

/**    *response 的响应码    *1, sendError(int sc)//发送错误代码    *2, sendError(int sc, java.lang.String msg) //发送错误代码及描述    *3, setStatus(int sc) //发送成功响应代码    *response 的响应头    *1, setDateHeader(java.lang.String name, long date)    *2, setHeader(java.lang.String name, java.lang.String value)    *3, setIntHeader(java.lang.String name, int value)    *  下面的和上面的作用一样但是是为了进行多值的添加    *  addDateHeader(java.lang.String name, long date)    *  addHeader(java.lang.String name, java.lang.String value)    *  addIntHeader(java.lang.String name, int value)    */   public void doGet(HttpServletRequest request, HttpServletResponse response)       throws ServletException, IOException {     //sendNum(response);     //sendRe(response);     //refresh(response);     //noCache(response);   }   //禁用浏览器缓存   public void noCache(HttpServletResponse response) {     response.setHeader("Cache-Control","no-cache");     response.setHeader("pragma","0");     response.setHeader("expires","no-cache");   }   //自动跳转   public void refresh(HttpServletResponse response) {     response.setHeader("refresh", "5;url=http://www.baidu.com");   }   //重定向的使用   public void sendRe(HttpServletResponse response) {     response.setStatus(302);     response.setHeader("Location", "http://www.baidu.com");   }    public void sendNum(HttpServletResponse response) throws IOException {     response.setStatus(200);     response.sendError(404);     response.sendError( 404, "ser accept your request but i don't want to you see my web page");   }  }