java之过滤器
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2022-04-20 12:09:37
form.jsp 1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8" import="java.util.*"%> 3
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form.jsp
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8" import="java.util.*"%> 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=UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <center><h3>用户登录</h3></center> 10 <body style="text-align: center;"> 11 <a href="<%=request.getContextPath()%>/CharacterServlet?name= 12 传智播客&password=123456">点击超链接</a> 13 <form action="<%=request.getContextPath() %>/CharacterServlet" method="get"> 14 <table border="1" width="600px" cellpadding="0" cellspacing="0" align="center"> 15 <tr> 16 <td height="30px" align="center">用户名:</td> 17 <td> <input type="text" name="username"/></td> 18 </tr> 19 <tr> 20 <td height="30px" align="center">密 码:</td> 21 <td> <input type="password" name="password"/></td> 22 </tr> 23 <tr> 24 <td height="30px" colspan="2" align="center"> 25 <input type="submit" value="登录" /> 26 <input type="reset" value="重置" /> 27 </td> 28 </tr> 29 </table> 30 </form> 31 </body> 32 </html>
过滤器:
1 /**
2 *
3 */
4 package cn.itcast.filter;
5
6 import java.io.IOException;
7 import java.io.UnsupportedEncodingException;
8
9 import javax.servlet.Filter;
10 import javax.servlet.FilterChain;
11 import javax.servlet.FilterConfig;
12 import javax.servlet.ServletException;
13 import javax.servlet.ServletRequest;
14 import javax.servlet.ServletResponse;
15 import javax.servlet.http.HttpServlet;
16 import javax.servlet.http.HttpServletRequest;
17 import javax.servlet.http.HttpServletRequestWrapper;
18 import javax.servlet.http.HttpServletResponse;
19
20 import com.sun.org.apache.regexp.internal.recompile;
21
22 /**TODO
23 * @author sqy
24 * 2018年8月5日上午9:46:57
25 */
26 public class CharacterFilter implements Filter{
27 @Override
28 public void init(FilterConfig filterConfig) throws ServletException {
29
30
31 }
32
33 @Override
34 public void doFilter(ServletRequest req, ServletResponse resp,
35 FilterChain chain) throws IOException, ServletException {
36 HttpServletRequest request = (HttpServletRequest) req;
37 HttpServletResponse response = (HttpServletResponse) resp;
38 //拦截所有请求 解决全站中文编码
39 //指定 request 和response的编码
40 request.setCharacterEncoding("utf-8");
41 response.setContentType("text/html;charset=utf-8");
42
43 CharacterRequest characterRequest = new CharacterRequest(request);
44 chain.doFilter(characterRequest, response);
45
46 }
47
48 @Override
49 public void destroy() {
50
51
52 }
53
54
55
56
57
58
59
60 }
61 /**
62 * TODO 针对request对象进行包装
63 * @author sqy
64 * 2018年8月5日上午11:12:18
65 */
66 class CharacterRequest extends HttpServletRequestWrapper{
67
68 public CharacterRequest(HttpServletRequest request) {
69 super(request);
70 }
71
72 public String getParameter(String name){
73 String value = super.getParameter(name);
74 if(value==null){
75 return null;
76 }
77 String method = super.getMethod();
78 if("get".equalsIgnoreCase(method)){
79 try {
80 value = new String(value.getBytes("iso-8859-1"),"utf-8");
81 } catch (UnsupportedEncodingException e) {
82 e.printStackTrace();
83 }
84
85 }
86
87 return value;
88
89 }
90
91 }
处理页面请求:
1 /**
2 *
3 */
4 package cn.itcast.chapter01.servlet;
5
6 import javax.servlet.http.HttpServlet;
7 import javax.servlet.http.HttpServletRequest;
8 import javax.servlet.http.HttpServletResponse;
9
10 /**TODO
11 * @author sqy
12 * 2018年8月5日上午9:42:11
13 */
14 public class CharacterServlet extends HttpServlet{
15 public void doGet(HttpServletRequest request,HttpServletResponse response){
16 System.out.println(request.getParameter("username"));
17 System.out.println(request.getParameter("password"));
18 }
19
20 public void doPost(HttpServletRequest request,HttpServletResponse response){
21 doGet(request, response);
22 }
23 }
web.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> 3 <display-name>chapter01</display-name> 4 5 6 <filter> 7 <filter-name>CharacterFilter</filter-name> 8 <filter-class>cn.itcast.filter.CharacterFilter</filter-class> 9 </filter> 10 11 <filter-mapping> 12 <filter-name>CharacterFilter</filter-name> 13 <url-pattern>/*</url-pattern> 14 </filter-mapping> 15 16 <servlet> 17 <servlet-name>CharacterServlet</servlet-name> 18 <servlet-class>cn.itcast.chapter01.servlet.CharacterServlet</servlet-class> 19 </servlet> 20 <servlet-mapping> 21 <servlet-name>CharacterServlet</servlet-name> 22 <url-pattern>/CharacterServlet</url-pattern> 23 </servlet-mapping> 24 25 </web-app>
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