* Request 和 Response 原理：
* request对象和response对象由服务器创建，我们只需要在service方法中使用这两个对象即可
* 继承体系结构：
ServletRequest <--继承-- HttpServletRequest <--实现--- RequestFacade
* Response：封装响应消息，设置响应消息
* 设置响应行：HTTP/1.1 200 ok
* setStatus(int code)：设置响应状态码
* 演示重定向：302
//简化版的重定向
response.sendRedirect("http://192.168.1.66:8080/zxc/one");
* 实现原理
//1.设置响应状态码为 302
response.setStatus(302);
//2.设置响应头 location
response.setHeader("location", "http://192.168.1.66:8080/zxc/one");
* 设置响应头：
* setHeader(String name,String value):
* setDateHeader(String name, long date)
* setIntHeader(String name, int value)
* 设置响应体：
* getOutputStream():发送字节数据
* 验证码：
* 防止恶意注册
* getWriter():发送字符数据
* 发送中文数据时，需要在获取流之前设置编码方式，并且要告诉客户端浏览器，服务器使用的编码方式
//简化版设置编码的方式
response.setContentType("text/html;charset=utf-8");
1 package Response; 2 3 import java.io.IOException; 4 import java.io.PrintWriter; 5 6 import javax.servlet.ServletException; 7 import javax.servlet.http.HttpServlet; 8 import javax.servlet.http.HttpServletRequest; 9 import javax.servlet.http.HttpServletResponse; 10 11 public class ResponseTest extends HttpServlet { 12 13 14 private static final long serialVersionUID = -3007244764565301466L; 15 16 public void doGet(HttpServletRequest request, HttpServletResponse response) 17 throws ServletException, IOException { 18 /* 19 * 设置响应消息体： 20 * getOutputStream():发送字节数据 21 * getWriter():发送字符数据 22 */ 23 /* 24 //设置流的编码方式 25 response.setCharacterEncoding("utf-8"); 26 //告诉客户端，服务器使用的编码方式 27 response.setHeader("content-type", "text/html;charset=utf-8"); 28 */ 29 30 //设置编码方式 31 response.setContentType("text/html;charset=utf-8"); 32 //获取字符输出流 33 PrintWriter pw = response.getWriter();//默认编码是 iso-8859-1 34 //设置数据 35 pw.write("<h3>你好啊 ！ response...</h3>"); 36 //刷新 37 pw.flush(); 38 } 39 40 public void doPost(HttpServletRequest request, HttpServletResponse response) 41 throws ServletException, IOException { 42 this.doGet(request, response); 43 44 } 45 46 }
* Request：封装请求消息，获取请求消息
* 获取请求消息：
* 获取请求行：GET /day08/req1?name=zs HTTP/1.1
* getMethod():获取请求方式
* getContextPath():获取虚拟目录
* getRequestURI():获取URI(统一资源标识符) /day07/one /one
* getRequestURL():获取URL(统一资源定位符) http://localhost:8080/day07/one
* getRemoteAddr():获取客户机的IP地址
* getQueryString():get方式获取请求参数
* 获取请求头：
* String getHeader(String name)
* long getDateHeader(String name)
* int getIntHeader(String name)
1 package Request; 2 3 import java.io.IOException; 4 5 import javax.servlet.ServletException; 6 import javax.servlet.http.HttpServlet; 7 import javax.servlet.http.HttpServletRequest; 8 import javax.servlet.http.HttpServletResponse; 9 10 public class RequestTest2 extends HttpServlet { 11 12 private static final long serialVersionUID = -5095708647887091449L; 13 14 public void doGet(HttpServletRequest request, HttpServletResponse response) 15 throws ServletException, IOException { 16 17 //获取请求头 18 String agent = request.getHeader("user-agent"); 19 System.out.println(agent); 20 21 if(agent.contains("MSIE")){ 22 System.out.println("IE 来了..."); 23 }else if(agent.contains("Firefox")){ 24 System.out.println("火狐 来了..."); 25 }else if(agent.contains("Chrome")){ 26 System.out.println("谷歌 来了..."); 27 }else{ 28 System.out.println("其他浏览器 来了..."); 29 } 30 31 System.err.println(".............................."); 32 } 33 34 public void doPost(HttpServletRequest request, HttpServletResponse response) 35 throws ServletException, IOException { 36 this.doGet(request, response); 37 38 } 39 40 }
* 获取请求体：封装post请求参数数据
* BufferedReader getReader():
* ServletInputStream getInputStream():
* 通用的获取请求参数的方式：
* String getParameter(String name):根据键名获取值
* String[] getParameterValues(String name):根据键名获取值的数组，一般用于复选框
* Map<String,String[]> getParameterMap():获取所有参数的map集合
* Enumeration getParameterNames():获取所有的键名枚举
1 package Request; 2 3 import java.io.IOException; 4 5 import javax.servlet.ServletException; 6 import javax.servlet.http.HttpServlet; 7 import javax.servlet.http.HttpServletRequest; 8 import javax.servlet.http.HttpServletResponse; 9 10 public class RequestTest extends HttpServlet { 11 12 private static final long serialVersionUID = 4919849090529066482L; 13 14 public void doGet(HttpServletRequest request, HttpServletResponse response) 15 throws ServletException, IOException { 16 17 //演示获取请求行数据 18 19 System.out.println(request.getMethod());//获取请求发式 20 System.out.println(request.getContextPath());//获取虚拟目录 21 System.out.println(request.getRequestURI());//获取URI 22 System.out.println(request.getRequestURL());//获取URL 23 System.out.println(request.getRemoteAddr());//获取ip 24 System.out.println(request.getQueryString());//获取请求参数 25 System.out.println(request.getProtocol());//获取协议 26 27 System.err.println("--------------------------"); 28 29 response.sendRedirect(request.getContextPath()+"/index.jsp"); 30 } 31 32 public void doPost(HttpServletRequest request, HttpServletResponse response) 33 throws ServletException, IOException { 34 this.doGet(request, response); 35 36 } 37 38 }
* 请求参数中文乱码问题：
1.通用：
//1.解码 iso
byte[] bytes = username.getBytes("iso-8859-1");
//2.编码 utf-8
username = new String(bytes, "utf-8");
2.post专用
//设置输入流的编码为 utf-8
request.setCharacterEncoding("utf-8");
* 域对象：代表一次请求
* 请求转发：
* 转发特点：
1.地址栏不发生变化
2.一次请求，一次响应
3.不能转发外部站点
1 package Request; 2 3 import java.io.IOException; 4 5 import javax.servlet.ServletException; 6 import javax.servlet.http.HttpServlet; 7 import javax.servlet.http.HttpServletRequest; 8 import javax.servlet.http.HttpServletResponse; 9 10 public class RequestTest7 extends HttpServlet { 11 12 private static final long serialVersionUID = 3744695995118989884L; 13 14 public void doGet(HttpServletRequest request, HttpServletResponse response) 15 throws ServletException, IOException { 16 17 System.out.println("req7 被访问了。。。"); 18 19 //存储数据 20 request.setAttribute("msg", "hehehe..."); 21 22 //转发至req 23 request.getRequestDispatcher("/req").forward(request, response); 24 } 25 26 public void doPost(HttpServletRequest request, HttpServletResponse response) 27 throws ServletException, IOException { 28 this.doGet(request, response); 29 30 } 31 32 }
* 重定向的特点：
1.地址栏发生变化
2.两次请求，两次响应
3.可以访问外部的站点
1 package Response; 2 3 import java.io.IOException; 4 5 import javax.servlet.ServletException; 6 import javax.servlet.http.HttpServlet; 7 import javax.servlet.http.HttpServletRequest; 8 import javax.servlet.http.HttpServletResponse; 9 10 public class ResponseTest2 extends HttpServlet { 11 12 /** 13 * 14 */ 15 private static final long serialVersionUID = -449184946348811489L; 16 17 public void doGet(HttpServletRequest request, HttpServletResponse response) 18 throws ServletException, IOException { 19 20 System.out.println("resp2 被访问了。。。"); 21 //演示重定向 22 //1.设置相应状态码 302 23 response.setStatus(302); 24 25 //2.设置相应头 location 26 //注意： http:// 不可以少 27 //response.setHeader("location", "http://192.168.1.66:8080/zxc/resp"); 28 29 //简化版的重定向 30 response.sendRedirect("http://192.168.1.66:8080/zxc/resp"); 31 } 32 33 public void doPost(HttpServletRequest request, HttpServletResponse response) 34 throws ServletException, IOException { 35 this.doGet(request, response); 36 37 } 38 39 }