{"id":5953,"date":"2024-04-17T00:45:29","date_gmt":"2024-04-16T16:45:29","guid":{"rendered":"http:\/\/zyg.luchers.cn\/?p=5953"},"modified":"2024-04-17T00:45:29","modified_gmt":"2024-04-16T16:45:29","slug":"%e5%8d%81%e4%b8%80%e3%80%81filter%e8%bf%87%e6%bb%a4%e5%99%a8","status":"publish","type":"post","link":"http:\/\/zyg.luchers.cn\/index.php\/2024\/04\/17\/%e5%8d%81%e4%b8%80%e3%80%81filter%e8%bf%87%e6%bb%a4%e5%99%a8\/","title":{"rendered":"\u5341\u4e00\u3001Filter\u8fc7\u6ee4\u5668"},"content":{"rendered":"

\u5341\u4e94\u3001Filter\u8fc7\u6ee4\u5668<\/h1>\n

1\u3001\u4ec0\u4e48\u662f\u8fc7\u6ee4\u5668<\/h2>\n

1\u3001\u5185\u5bb9<\/h3>\n

1\u3001Filter\u8fc7\u6ee4\u5668\u662fjavaweb\u7684\u4e09\u5927\u7ec4\u4ef6\u4e4b\u4e00\u3002\u4e09\u5927\u7ec4\u4ef6\u5206\u522b\u4e3a\uff1aservlet\u7a0b\u5e8f\u3001Listener\u76d1\u542c\u5668\u3001Filter\u8fc7\u6ee4\u5668<\/p>\n

2\u3001Filter\u8fc7\u6ee4\u5668\u662fJavaEE\u7684\u89c4\u8303\u3002\u662f\u4e00\u4e2a\u63a5\u53e3<\/p>\n

3\u3001FIlter\u7684\u4f5c\u7528\uff1a\u62e6\u622a\u8bf7\u6c42<\/strong>\uff0c\u8fc7\u6ee4\u54cd\u5e94\u3002<\/p>\n

2\u3001\u5e94\u7528\u573a\u666f<\/h3>\n

1\u3001\u6743\u9650\u68c0\u67e5<\/p>\n

2\u3001\u65e5\u8bb0\u64cd\u4f5c<\/p>\n

3\u3001\u4e8b\u52a1\u7ba1\u7406<\/p>\n

2\u3001Filter\u4f53\u9a8c<\/h2>\n

2.1\u3001\u9700\u6c42<\/h3>\n

1\u3001\u5728web\u5de5\u7a0b\u4e0b\uff0c\u6709\u4e2aadmin\u76ee\u5f55\u3002\u8fd9\u4e2aadmin\u76ee\u5f55\u4e0b\u7684\u6240\u6709\u8d44\u6e90\uff08html\u3001jsp\u3001jpg\u3001\u7b49\u7b49\uff09\u90fd\u662f\u9700\u8981\u5728\u7528\u6237\u767b\u5f55\u4e4b\u540e\u624d\u5141\u8bb8\u8bbf\u95ee\u7684\u3002<\/p>\n

2.2\u3001Filter\u5de5\u4f5c\u6d41\u7a0b\u56fe<\/h3>\n

\"image-20230507090313617\"<\/div><\/p>\n

1\u3001\u601d\u8003\uff1a\u6839\u636e\u4e4b\u524d\u6211\u4eec\u5b66\u8fc7\u5185\u5bb9\u3002\u6211\u4eec\u77e5\u9053\uff0c\u7528\u6237\u767b\u5f55\u4e4b\u540e\u90fd\u4f1a\u628a\u7528\u6237\u767b\u5f55\u7684\u4fe1\u606f\u4fdd\u5b58\u5230 Session \u57df\u4e2d\u3002\u6240\u4ee5\u8981\u68c0\u67e5\u7528\u6237\u662f\u5426 \u767b\u5f55\uff0c\u53ef\u4ee5\u5224\u65ad Session \u4e2d\u5426\u5305\u542b\u6709\u7528\u6237\u767b\u5f55\u7684\u4fe1\u606f\u5373\u53ef\uff01\uff01\uff01<\/p>\n

2.3\u3001Filter\u8fc7\u6ee4\u5668\u7684\u4f7f\u7528\u6b65\u9aa4<\/h3>\n

1\u3001\u7f16\u5199\u4e00\u4e2a\u7c7b\u53bb\u5b9e\u73b0Filter\u63a5\u53e3<\/p>\n

2\u3001\u5b9e\u73b0\u63a5\u53e3\u4e2d\u7684\u7684doFilter()<\/p>\n

3\u3001\u5230web.xml\u4e2d\u53bb\u914d\u7f6eFIlter\u7684\u62e6\u622a\u8def\u5f84<\/p>\n

2.4\u3001\u4ee3\u7801\u5b9e\u73b0<\/h3>\n

1\u3001Filter\u7684\u4ee3\u7801<\/h4>\n

1\u3001AdminFilter\u7c7b<\/p>\n

package com.qt.filter;\n\nimport javax.servlet.*;\nimport javax.servlet.http.HttpServlet;\nimport javax.servlet.http.HttpServletRequest;\nimport javax.servlet.http.HttpSession;\nimport java.io.IOException;\n\npublic class AdminFilter implements Filter {\n\n    public AdminFilter() {\n        System.out.println("111 \u6784\u9020\u5668\u65b9\u6cd5");\n    }\n\n    @Override\n    public void init(FilterConfig filterConfig) throws ServletException {\n        System.out.println("222 init");\n\n\/\/        1\u3001\u83b7\u53d6filter\u7684\u540d\u79f0\uff1afilter-name\n        System.out.println("filter-name:"+filterConfig.getFilterName());\n\n\/\/        2\u3001\u83b7\u53d6web.xml\u4e2d\u7684init-param\u914d\u7f6e\u6587\u4ef6\n        System.out.println("init-param:"+filterConfig.getInitParameter("username"));\n        System.out.println("init-param:"+filterConfig.getInitParameter("url"));\n\n\/\/        3\u3001\u83b7\u53d6ServletContext\u5bf9\u8c61\n        System.out.println("filter-\u5bf9\u8c61\u4e3a\uff1a"+filterConfig.getServletContext());\n\/\/\n    }\n\n    \/**\n     * \u7528\u4e8e\u62e6\u622a\u8bf7\u6c42\u7684\u65b9\u6cd5\n     * @param servletRequest\n     * @param servletResponse\n     * @param filterChain\n     * @throws IOException\n     * @throws ServletException\n     *\/\n    @Override\n    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {\n\n        System.out.println("333 doFilter");\n\n        HttpServletRequest httpServletRequest= (HttpServletRequest) servletRequest;\n\n        HttpSession session = httpServletRequest.getSession();\n        Object user = session.getAttribute("user");\n        if(user==null){\n            servletRequest.getRequestDispatcher("\/login.jsp").forward(servletRequest,servletResponse);\n            return;\n        }else {\n            \/\/\u8ba9\u7a0b\u5e8f\u7ee7\u7eed\u5f80\u4e0b\u8bbf\u95ee\u7528\u6237\u7684\u76ee\u6807\u8d44\u6e90\n            filterChain.doFilter(servletRequest,servletResponse);\n        }\n    }\n\n    @Override\n    public void destroy() {\n        System.out.println("444 destroy");\n    }\n}<\/code><\/pre>\n
2\u3001web.xml\u4e2d\u7684\u914d\u7f6e\u6587\u4ef6<\/h4>\n
1\u3001Filter\u8fc7\u6ee4\u5668\u4e2d\u7684web.xml \u914d\u7f6e<\/p>\n
<!--    \u914d\u7f6efilter\u8fc7\u6ee4\u5668\u7684\u62e6\u622a\u8def\u5f84-->\n    <filter-mapping>\n<!--        \u8868\u793a\u5f53\u524d\u7684\u62e6\u622a\u8def\u5f84\u7ed9\u54ea\u4e2afilter\u4f7f\u7528-->\n        <filter-name>AdminFilter<\/filter-name>\n<!--        \u914d\u7f6e\u62e6\u622a\u8def\u5f84\n            \/\u8868\u793a\u8bf7\u6c42\u5730\u5740\u4e3a\uff1ahttp:\/\/ip:port\/\u5de5\u7a0b\u8def\u5f84\/  \u6620\u5c04\u5230idea\u7684\u6587\u672c\u8def\u5f84\n            \/admin\/* \u8868\u793a\uff1a\u8bf7\u6c42\u5730\u5740\uff1ahttp:\/\/ip:port\/\u5de5\u7a0b\u8def\u5f84\/admin\/*\n-->\n        <url-pattern>\/admin\/*<\/url-pattern>\n    <\/filter-mapping><\/code><\/pre>\n
2\u3001Servlet\u7a0b\u5e8f\u7684web.xml\u914d\u7f6e<\/p>\n
<servlet>\n    <servlet-name>LoginServlet<\/servlet-name>\n    <servlet-class>com.qt.servlet.LoginServlet<\/servlet-class>\n<\/servlet>\n<servlet-mapping>\n    <servlet-name>LoginServlet<\/servlet-name>\n    <url-pattern>\/loginServlet<\/url-pattern>\n<\/servlet-mapping><\/code><\/pre>\n
3\u3001\u5b8c\u6574\u7684\u7528\u6237\u767b\u5f55\u9875\u9762<\/h4>\n
1\u3001login.jsp<\/p>\n
<%@ page contentType="text\/html;charset=UTF-8" language="java" %>\n<html>\n<head>\n    <title>Title<\/title>\n<\/head>\n<body>\n    \u8fd9\u662f\u767b\u5f55\u9875\u9762  login.jsp\u9875\u9762\n    <form action="http:\/\/localhost:8080\/15_Filter\/loginServlet" method="get">\n        \u7528\u6237\u540d\uff1a<input type="text" name="username" \/><br\/>\n        \u5bc6\u7801\uff1a<input type="password" name="password">\n        <input type="submit" value="\u767b\u5f55">\n\n    <\/form>\n<\/body>\n<\/html><\/code><\/pre>\n
2\u3001a.jsp \u9875\u9762<\/p>\n
<%@ page contentType="text\/html;charset=UTF-8" language="java" %>\n<html>\n<head>\n    <title>Title<\/title>\n<\/head>\n<body>\n    \u6211\u662fa.jsp\u6587\u4ef6\n    <%\n        System.out.println("a.jsp\u9875\u9762\u6267\u884c\u4e86");\n        Object user = session.getAttribute("user");\n        if(user==null){\n            request.getRequestDispatcher("\/login.jsp").forward(request,response);\n            return;\n        }\n    %>\n<\/body>\n<\/html><\/code><\/pre>\n
3\u3001FIlter\u7684\u751f\u547d\u5468\u671f<\/h2>\n
3.1\u3001\u751f\u547d\u5468\u671f\u5305\u542b\u7684\u65b9\u6cd5<\/h3>\n
1\u3001\u5b9e\u73b0FIlter\u63a5\u53e3\u7684\u5b9e\u73b0\u7c7b\u5c31\u4f1a\u6709\u8fd9\u4e9b\u65b9\u6cd5<\/p>\n
1\u3001\u6784\u9020\u5668\u65b9\u6cd5<\/h4>\n
1\u3001\u7b2c\u4e00\u4e2a\u6267\u884c<\/p>\n
2\u3001\u4ee3\u7801<\/p>\n
public xxxxx() {    \/\/xxxxx\u662f\u6784\u9020\u5668\u540d\u79f0\n}<\/code><\/pre>\n
3\u3001\u6784\u9020\u5668\u9700\u8981\u81ea\u5df1\u6dfb\u52a0<\/p>\n
2\u3001init\u521d\u59cb\u5316\u65b9\u6cd5<\/h4>\n
1\u3001\u7b2c\u4e8c\u4e2a\u6267\u884c<\/p>\n
2\u3001\u4ee3\u7801<\/p>\n
@Override\npublic void init(FilterConfig filterConfig) throws ServletException {\n\n}<\/code><\/pre>\n
3\u3001doFilter\u8fc7\u6ee4\u65b9\u6cd5<\/h4>\n
1\u3001\u7b2c\u4e09\u4e2a\u6267\u884c<\/p>\n
2\u3001\u6bcf\u6b21\u62e6\u622a\u5230\u8bf7\u6c42\uff0c\u5c31\u4f1a\u6267\u884c<\/p>\n
3\u3001\u4ee3\u7801<\/p>\n
@Override\npublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {\n\n}<\/code><\/pre>\n
4\u3001destroy\u9500\u6bc1<\/h4>\n
1\u3001\u6700\u540e\u4e00\u4e2a\u6267\u884c<\/p>\n
2\u3001\u505c\u6b62web\u5de5\u7a0b\u65f6\uff0c\u624d\u4f1a\u6267\u884c\u3002<\/p>\n
4\u3001FilterConfig\u7c7b<\/h2>\n
4.1\u3001\u5185\u5bb9<\/h3>\n
1\u3001FIlterConfig\u662fFIlter\u8fc7\u6ee4\u5668\u7684\u914d\u7f6e\u6587\u4ef6\u7c7b<\/p>\n
2\u3001tomcat\u6bcf\u6b21\u521b\u5efaFIlter\u65f6\u5019\uff0c\u5c31\u4f1a\u540c\u65f6\u521b\u5efa\u4e00\u4e2aFIlterConfig\u7c7b\u3002\u8fd9\u91cc\u5305\u542b\u4e86FIlter\u914d\u7f6e\u6587\u4ef6\u7684\u914d\u7f6e\u4fe1\u606f\u3002<\/p>\n
4.2\u3001FilterConfig\u7c7b\u7684\u4f5c\u7528<\/h3>\n
1\u3001\u5185\u5bb9<\/h4>\n
1\u3001\u83b7\u53d6filter\u8fc7\u6ee4\u5668\u7684\u914d\u7f6e\u5185\u5bb9<\/p>\n
2\u3001\u83b7\u53d6Filter\u7684\u540d\u79f0\uff1afilter-name\u7684\u5185\u5bb9<\/p>\n
3\u3001\u83b7\u53d6Filter\u4e2d\u914d\u7f6e\u7684init-param\u521d\u59cb\u5316\u53c2\u6570<\/p>\n
4\u3001\u83b7\u53d6ServletContext\u5bf9\u8c61<\/p>\n
2\u3001\u4f8b\u5b50<\/h4>\n
1\u3001java\u4ee3\u7801<\/p>\n
\"image-20230507091828559\"<\/div><\/p>\n
2\u3001web.xml\u914d\u7f6e\u6587\u4ef6<\/p>\n
\"image-20230507091938687\"<\/div><\/p>\n
5\u3001FilterChain\u8fc7\u6ee4\u5668\u94fe<\/h2>\n
5.1\u3001\u5185\u5bb9<\/h3>\n
1\u3001FilterChain\uff1a\u662f\u8fc7\u6ee4\u5668\u94fe\uff0c\u662f\u8ba9\u591a\u4e2a\u8fc7\u6ee4\u5668\u5982\u4f55\u540c\u65f6\u5de5\u4f5c\u7684<\/p>\n
5.2\u3001\u56fe\u89e3<\/h3>\n
\"image-20230507092159088\"<\/div><\/p>\n
1\u3001FilterChain.doFilter()\u65b9\u6cd5\u7684\u4f5c\u7528<\/h4>\n
1\u3001\u6267\u884c\u4e0b\u4e00\u4e2aFIlter\u8fc7\u6ee4\u5668\uff08\u5982\u679c\u6709\u7684\u8bdd\uff09<\/p>\n
2\u3001\u6267\u884c\u76ee\u6807\u8d44\u6e90\uff08\u6ca1\u6709Filter)<\/p>\n
2\u3001\u5728\u591a\u4e2aFIlter\u8fc7\u6ee4\u5668\u6267\u884c\u7684\u65f6\u5019\uff0c\u5b83\u4eec\u7684\u6267\u884c\u987a\u5e8f\u662f\u7531\u4ed6\u4eec\u7684web.xml\u4e2d\u4ece\u4e0a\u5230\u4e0b\u914d\u7f6e\u7684\u987a\u5e8f\u51b3\u5b9a\u7684\uff01\uff01\uff01<\/u><\/h4>\n
3\u3001\u591a\u4e2aFilter\u8fc7\u6ee4\u5668\u6267\u884c\u7684\u7279\u70b9<\/h4>\n
1\u3001\u6240\u6709FIlter\u548c\u76ee\u6807\u8d44\u6e90\u9ed8\u8ba4\u90fd\u6267\u884c\u5728\u540c\u4e00\u4e2a\u7ebf\u7a0b\u4e2d<\/p>\n
2\u3001\u591a\u4e2aFilter\u5171\u540c\u6267\u884c\u7684\u65f6\u5019\uff0c\u5b83\u4eec\u90fd\u4f7f\u7528\u540c\u4e00\u4e2aRequest\u5bf9\u8c61<\/p>\n
6\u3001Filter\u7684\u62e6\u622a\u8def\u5f84<\/h2>\n
6.1\u3001\u7cbe\u786e\u5339\u914d<\/h3>\n
1\u3001\u5185\u5bb9<\/p>\n
\"image-20230507092632583\"<\/div><\/p>\n
6.2\u3001\u76ee\u5f55\u5339\u914d<\/h3>\n
1\u3001\u5185\u5bb9<\/p>\n
\"image-20230507092644624\"<\/div><\/p>\n
6.3\u3001\u540e\u7f00\u540d\u5339\u914d<\/h3>\n
1\u3001\u5185\u5bb9<\/p>\n
\"image-20230507092700623\"<\/div><\/p>\n
6.4\u3001Filter \u8fc7\u6ee4\u5668\u5b83\u53ea\u5173\u5fc3\u8bf7\u6c42\u7684\u5730\u5740\u662f\u5426\u5339\u914d\uff0c\u4e0d\u5173\u5fc3\u8bf7\u6c42\u7684\u8d44\u6e90\u662f\u5426\u5b58\u5728\uff01\uff01\uff01<\/h3>\n
7\u3001ThreadLocal\u7684\u4f7f\u7528<\/h2>\n
7.1\u3001\u5185\u5bb9<\/h3>\n
1\u3001ThreadLocal\u7684\u4f5c\u7528\uff0c\u662f\u89e3\u51b3\u591a\u7ebf\u7a0b\u7684\u6570\u636e\u5b89\u5168\u95ee\u9898<\/p>\n
2\u3001ThreadLocal\uff1a\u53ef\u4ee5\u7ed9\u5f53\u524d\u7ebf\u7a0b\u5173\u8054\u7684\u4e00\u4e2a\u6570\u636e\uff08\u53ef\u4ee5\u662f\u666e\u901a\u53d8\u91cf\u3001\u53ef\u4ee5\u662f\u5bf9\u8c61\u3001\u53ef\u4ee5\u662f\u6570\u7ec4\u3001\u96c6\u5408\uff09<\/p>\n
7.2\u3001ThreadLocal\u7684\u7279\u70b9<\/h3>\n
1\u3001ThreadLocal\u53ef\u4ee5\u4e3a\u5f53\u524d\u7ebf\u7a0b\u5173\u8054\u4e00\u4e2a\u6570\u636e\u3002\uff08\u5b83\u53ef\u4ee5\u50cfMap\u4e00\u6837\u5b58\u53d6\u6570\u636e\u3001key\u4e3a\u5f53\u524d\u7ebf\u7a0b\uff09<\/p>\n
2\u3001\u6bcf\u4e00\u4e2aThreadLocal\u5bf9\u8c61\uff0c\u53ea\u80fd\u4e3a\u5f53\u524d\u7ebf\u7a0b\u5173\u8054\u4e00\u4e2a\u6570\u636e\uff0c\u5982\u679c\u8981\u4e3a\u5f53\u524d\u7ebf\u7a0b\u5173\u8054\u591a\u4e2a\u6570\u636e\uff0c\u5c31\u9700\u8981\u4f7f\u7528\u591a\u4e2aThreadLocal\u5bf9\u8c61\u5b9e\u4f8b\u3002<\/p>\n
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