JavaWeb14.4【servlet&http&request：Request的其他功能】
阿新 • • 發佈：2021-06-30
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 9 <form action="/day14/RequestDemo4" method="post"> 10 <input type="text" placeholder="請輸入使用者名稱" name="username"><br> 11 <input type="text" placeholder="請輸入密碼" name="password"><br> 12 <input type="checkbox" name="hobby" value="game">遊戲 13 <input type="checkbox" name="hobby" value="study">學習 14 <br> 15 <input type="submit" value="註冊"> 16 </form> 17 18 </body> 19 </html>
1 package com.haifei.web.request; 2 3 import javax.servlet.ServletException; 4 import javax.servlet.annotation.WebServlet; 5 import javax.servlet.http.HttpServlet; 6 import javax.servlet.http.HttpServletRequest; 7 import javax.servlet.http.HttpServletResponse;8 import java.io.IOException; 9 import java.util.Enumeration; 10 import java.util.Map; 11 import java.util.Set; 12 13 /** 14 * request的其他功能 之 獲取請求引數通用方式 15 */ 16 @WebServlet("/RequestDemo4") 17 public class RequestDemo4 extends HttpServlet { 18 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 19 //post 獲取請求引數 20 21 //1 根據引數名稱獲取引數值 22 String username = request.getParameter("username"); 23 /*System.out.println("post"); 24 System.out.println(username);*/ 25 /* 26 <form action="/day14/RequestDemo4" method="post"> 27 http://localhost:8080/day14/regist2.html 28 29 http://localhost:8080/day14/RequestDemo4 30 31 post 32 yubaby 33 */ 34 35 //2 根據引數名稱獲取引數值的陣列 36 String[] hobbies = request.getParameterValues("hobby"); //獲取勾選的複選框的值 37 /*for (String hobby: hobbies){ 38 System.out.println(hobby); 39 }*/ 40 41 //3 獲取所有請求的引數名稱 42 Enumeration<String> parameterNames = request.getParameterNames(); 43 /*while (parameterNames.hasMoreElements()){ 44 String name = parameterNames.nextElement(); 45 System.out.println(name); 46 String value = request.getParameter(name); 47 System.out.println(value); 48 System.out.println("-------------------"); 49 }*/ 50 51 //4 獲取所有引數的map集合 52 Map<String, String[]> parameterMap = request.getParameterMap(); 53 Set<String> keySet = parameterMap.keySet(); 54 for (String name : keySet) { //iter+回車 快速生成foreach 55 System.out.println(name); 56 String[] values = parameterMap.get(name); 57 for (String value : values) { 58 System.out.println(value); 59 } 60 System.out.println("======================"); 61 } 62 } 63 64 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 65 66 /*//get 獲取請求引數 67 68 //1 根據引數名稱獲取引數值 69 String username = request.getParameter("username"); 70 System.out.println("get"); 71 System.out.println(username);*/ 72 73 /* 74 <form action="/day14/RequestDemo4" method="get"> 75 http://localhost:8080/day14/regist2.html 76 77 http://localhost:8080/day14/RequestDemo4?username=haifei&password=222 78 79 get 80 haifei 81 */ 82 83 //PS 既然在獲取請求引數這方面，doGet和doPost中的程式碼通用，那麼： 84 this.doPost(request, response); 85 } 86 }
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 9 <form action="/day14/RequestDemo5" method="post"> 10 <input type="text" placeholder="請輸入使用者名稱" name="username"><br> 11 <input type="text" placeholder="請輸入密碼" name="password"><br> 12 <input type="checkbox" name="hobby" value="game">遊戲 13 <input type="checkbox" name="hobby" value="study">學習 14 <br> 15 <input type="submit" value="註冊"> 16 </form> 17 18 </body> 19 </html>
1 package com.haifei.web.request; 2 3 import javax.servlet.ServletException; 4 import javax.servlet.annotation.WebServlet; 5 import javax.servlet.http.HttpServlet; 6 import javax.servlet.http.HttpServletRequest; 7 import javax.servlet.http.HttpServletResponse; 8 import java.io.IOException; 9 10 /** 11 * request的其他功能 之 獲取請求引數通用方式 12 * 中文亂碼問題 13 */ 14 @WebServlet("/RequestDemo5") 15 public class RequestDemo5 extends HttpServlet { 16 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 17 //設定流的編碼 解決post中文亂碼問題 18 request.setCharacterEncoding("utf-8"); 19 String username = request.getParameter("username"); 20 System.out.println(username); 21 } 22 23 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 24 //tomcat8及後已經將get方式亂碼問題解決了 25 this.doPost(request, response); 26 } 27 }
1 package com.haifei.web.request; 2 3 import javax.servlet.RequestDispatcher; 4 import javax.servlet.ServletException; 5 import javax.servlet.annotation.WebServlet; 6 import javax.servlet.http.HttpServlet; 7 import javax.servlet.http.HttpServletRequest; 8 import javax.servlet.http.HttpServletResponse; 9 import java.io.IOException; 10 11 /** 12 * request的其他功能 之 請求轉發 和 資料共享 13 */ 14 @WebServlet("/RequestDemo6") 15 public class RequestDemo6 extends HttpServlet { 16 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 17 System.out.println("RequestDemo6被訪問了。。。"); 18 19 //轉發之前儲存資料到request域中 20 request.setAttribute("msg", "hello"); //鍵值對 21 22 // 轉發資源 到RequestDemo7 23 /*RequestDispatcher requestDispatcher = request.getRequestDispatcher("/RequestDemo7"); 24 requestDispatcher.forward(request, response);*/ 25 request.getRequestDispatcher("/RequestDemo7").forward(request, response); 26 //request.getRequestDispatcher("http://www.itcast.cn").forward(request,response); //轉發失敗404 只能轉發到當前伺服器內部資源中 27 28 /* 29 http://localhost:8080/day14/RequestDemo6 30 31 RequestDemo6被訪問了。。。 32 RequestDemo7被訪問了。。。 33 */ 34 } 35 36 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 37 this.doPost(request, response); 38 } 39 }
1 package com.haifei.web.request; 2 3 import javax.servlet.ServletException; 4 import javax.servlet.annotation.WebServlet; 5 import javax.servlet.http.HttpServlet; 6 import javax.servlet.http.HttpServletRequest; 7 import javax.servlet.http.HttpServletResponse; 8 import java.io.IOException; 9 10 /** 11 * request的其他功能 之 請求轉發 和 資料共享 12 */ 13 @WebServlet("/RequestDemo7") 14 public class RequestDemo7 extends HttpServlet { 15 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 16 System.out.println("RequestDemo7被訪問了。。。"); 17 18 //獲取來自RequestDemo6的資料 19 Object msg = request.getAttribute("msg"); 20 System.out.println(msg); //hello 21 } 22 23 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 24 this.doPost(request, response); 25 } 26 }
1 package com.haifei.web.request; 2 3 import javax.servlet.ServletContext; 4 import javax.servlet.ServletException; 5 import javax.servlet.annotation.WebServlet; 6 import javax.servlet.http.HttpServlet; 7 import javax.servlet.http.HttpServletRequest; 8 import javax.servlet.http.HttpServletResponse; 9 import java.io.IOException; 10 11 /** 12 * request的其他功能 之 獲取ServletContext 13 */ 14 @WebServlet("/RequestDemo8") 15 public class RequestDemo8 extends HttpServlet { 16 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 17 ServletContext servletContext = request.getServletContext(); 18 System.out.println(servletContext); //org.apache.catalina.core.ApplicationContextFacade@666293eb 19 } 20 21 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 22 this.doPost(request, response); 23 } 24 }