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java之过滤器

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互联网集市收集整理的这篇技术教程文章主要介绍了java之过滤器，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含5238字，纯文字阅读大概需要8分钟。

内容图文

form.jsp

技术分享图片 技术分享图片 
                 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>&nbsp;<input type="text" name="username"/></td>18</tr>19<tr>20<td height="30px" align="center">密&nbsp;码:</td>21<td>&nbsp;<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"/>&nbsp;&nbsp;&nbsp;&nbsp;26<input type="reset" value="重置"/>27</td>28</tr>29</table>30</form>31</body>32</html>
View Code

过滤器:

技术分享图片 技术分享图片 
                 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
28publicvoid init(FilterConfig filterConfig) throws ServletException {
293031    }
3233    @Override
34publicvoid 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");
4243          CharacterRequest characterRequest = new CharacterRequest(request);
44         chain.doFilter(characterRequest, response);
4546    }
4748    @Override
49publicvoid destroy() {
505152    }
5354555657585960}
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*/66class CharacterRequest extends HttpServletRequestWrapper{
6768public CharacterRequest(HttpServletRequest request) {
69super(request);
70    }
7172public String getParameter(String name){
73         String value = super.getParameter(name);
74if(value==null){
75returnnull;
76        }
77         String method = super.getMethod();
78if("get".equalsIgnoreCase(method)){
79try {
80                 value = new String(value.getBytes("iso-8859-1"),"utf-8");
81             } catch (UnsupportedEncodingException e) {
82                e.printStackTrace();
83            }
8485        }
8687return value;
8889    }
9091 }
View Code

处理页面请求:

技术分享图片 技术分享图片 
                 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{
15publicvoid doGet(HttpServletRequest request,HttpServletResponse response){
16         System.out.println(request.getParameter("username"));
17         System.out.println(request.getParameter("password"));
18    }
1920publicvoid doPost(HttpServletRequest request,HttpServletResponse response){
21        doGet(request, response);
22    }
23 }
View Code

web.xml

技术分享图片 技术分享图片 
                 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>1011<filter-mapping>12<filter-name>CharacterFilter</filter-name>13<url-pattern>/*</url-pattern>14</filter-mapping>1516<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>2425</web-app>
View Code

 

原文：https://www.cnblogs.com/sqy-yyr/p/9424905.html

内容总结

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