1.<a href="customerServlet?method=add">Add</a> 这里method=add不能有空格,否则报错(空指针异常)
1 <%@ page language="java" contentType="text/html; charset=ISO-8859-1" 2 pageEncoding="ISO-8859-1"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 <a href="customerServlet?method=add">Add</a> 11 <br> 12 <br> 13 14 <a href="customerServlet?method=query">Query</a> 15 <br> 16 <br> 17 18 <a href="customerServlet?method=delete">Delete</a> 19 <br> 20 <br> 21 22 </body> 23 </html>
1 package com.ouyang.dao;
2
3 import java.io.IOException;
4
5 import javax.servlet.ServletException;
6 import javax.servlet.annotation.WebServlet;
7 import javax.servlet.http.HttpServlet;
8 import javax.servlet.http.HttpServletRequest;
9 import javax.servlet.http.HttpServletResponse;
10
11 @WebServlet("/customerServlet")
12 public class CustomerServlet extends HttpServlet {
13 private static final long serialVersionUID = 1L;
14
15 protected void doGet(HttpServletRequest request,
16 HttpServletResponse response) throws ServletException, IOException {
17 doPost(request, response);
18 }
19
20 protected void doPost(HttpServletRequest request,
21 HttpServletResponse response) throws ServletException, IOException {
22 String method = request.getParameter("method");
23
24 switch (method) {
25 case "add":
26 add(request, response);
27 break;
28 case "query":
29 query(request, response);
30 break;
31 case "delete":
32 delete(request, response);
33 break;
34
35 }
36
37 }
38
39 private void delete(HttpServletRequest request, HttpServletResponse response)
40 throws ServletException, IOException {
41 System.out.println("delete");
42 }
43
44 private void query(HttpServletRequest request, HttpServletResponse response)
45 throws ServletException, IOException {
46 System.out.println("query");
47 }
48
49 private void add(HttpServletRequest request, HttpServletResponse response)
50 throws ServletException, IOException {
51 System.out.println("add");
52
53 }
54
55 }
2.url-pattern 中在建立Servlet时前面不应该加"/".否则会报错
时间： 2024-10-29 19:11:26