JavaWeb14.1【servlet&http&request：Servlet的體系結構、相關配置】
阿新 • • 發佈：2021-06-29
1 package com.haifei.web.servlet; 2 3 import javax.servlet.*; 4 import javax.servlet.annotation.WebServlet; 5 import java.io.IOException; 6 7 8 //@WebServlet("./demo1") //專案啟動是會報錯 9 @WebServlet("/demo1") //千萬不要寫成"./demo1" 10 public class ServletDemo1 implements Servlet { 11 12 13 @Override 14public void init(ServletConfig servletConfig) throws ServletException { 15 16 } 17 18 @Override 19 public ServletConfig getServletConfig() { 20 return null; 21 } 22 23 @Override 24 public void service(ServletRequest servletRequest, ServletResponse servletResponse) throwsServletException, IOException { 25 System.out.println("demo1...."); 26 //http://localhost/demo1 27 } 28 29 @Override 30 public String getServletInfo() { 31 return null; 32 } 33 34 @Override 35 public void destroy() { 36 37 } 38 }
1 package com.haifei.web.servlet;2 3 import javax.servlet.GenericServlet; 4 import javax.servlet.ServletException; 5 import javax.servlet.ServletRequest; 6 import javax.servlet.ServletResponse; 7 import javax.servlet.annotation.WebServlet; 8 import java.io.IOException; 9 10 @WebServlet("/demo2") 11 public class ServletDemo2 extends GenericServlet { 12 @Override 13 public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException { 14 System.out.println("demo2...."); 15 //http://localhost/demo2 16 } 17 }
1 package com.haifei.web.servlet; 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 @WebServlet("/demo3") 11 public class ServletDemo3 extends HttpServlet { 12 @Override 13 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 14 // super.doGet(req, resp); 15 System.out.println("doGet....."); 16 /* 17 瀏覽器直接請求是doGet方式 18 19 瀏覽器位址列http://localhost/demo3 20 控制檯輸出doGet..... 21 */ 22 } 23 24 @Override 25 protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 26 // super.doPost(req, resp); 27 System.out.println("doPost....."); 28 /* 29 截止目前學到的知識，只能通過表單實現doPost方式 30 31 http://localhost/login.html 32 隨便輸入，點選提交，自動跳轉到http://localhost/demo3 33 控制檯輸出doPost..... 34 */ 35 } 36 }
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 <form action="/demo3" method="post"> 9 <input name="username"> 10 <input type="submit" value="提交"> 11 </form> 12 </body> 13 </html>
1 package com.haifei.web.servlet; 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 * Servlet路徑配置方式 12 */ 13 //@WebServlet({"/d4","/dd4","/ddd4"}) 14 //@WebServlet("/user/demo4") 15 //@WebServlet("/user/*") //*是萬用字元，寫啥都行 16 //@WebServlet("/*") 17 @WebServlet("*.do") //注意這種方式前面不要加/，並且do寫其他詞也行，隨便，比如.action等 18 public class ServletDemo4 extends HttpServlet { 19 @Override 20 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 21 System.out.println("demo4 .... doGet"); 22 /* 23 瀏覽器位址列訪問 24 http://localhost/d4 25 或 26 http://localhost/dd4 27 或 28 http://localhost/ddd4 29 均可令控制檯輸出demo4 .... doGet 30 */ 31 32 //http://localhost/user/demo4 33 34 /* 35 http://localhost/user/ 36 http://localhost/user/hehe 37 http://localhost/user/heihei 38 http://localhost/user/haha 39 ... 40 */ 41 42 /* 43 http://localhost/ 44 http://localhost/qdu 45 http://localhost/fuck 46 ... 47 */ 48 /* 49 疑問：例如ServletDemo3類中設定了@WebServlet("/demo3") 50 此時ServletDemo4類中設定了@WebServlet("/*") 51 當瀏覽器訪問http://localhost/demo3時會怎樣 52 答案：doGet..... 53 解析：萬用字元*的優先順序最低，即其他方式都訪問不到時才會利用*訪問 54 */ 55 56 /* 57 http://localhost/.do 58 http://localhost/demo4.do 59 http://localhost/xxx.do 60 .... 61 */ 62 } 63 }
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