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Filter过滤器的使用
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作者: strawberry79(http://strawberry79.itpub.net)
发表于: 2005.02.28 13:35
分类: Struts技术研究
出处: http://strawberry79.itpub.net/post/329/19918
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发表于: 2005.02.28 13:35
分类: Struts技术研究
出处: http://strawberry79.itpub.net/post/329/19918
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本篇文章是介绍javax.servlet包中Filter的几个功能,一是字符编码过滤,二是拦截指文件夹中的文件,实现登录验证.
本篇文章是介绍javax.servlet包中Filter的几个功能,一是字符编码过滤,二是拦截指文件夹中的文件,实现登录验证.实现以上两个功能需以下几个步骤: 1、实现javax.servlet.Filter接口，编写两个类，如下： /** * 作用：过滤编码 */ package filter; import java.io.IOException; import javax.servlet.*; import javax.servlet.http.HttpServletRequest; public class EncodingFilter implements Filter { protected FilterConfig filterConfig; private String targetEncoding; public EncodingFilter() { targetEncoding = "gb2312";//直接初始化0912 } public void init(FilterConfig filterconfig) throws ServletException { filterConfig = filterconfig; //targetEncoding = filterconfig.getInitParameter("encoding");//web.xml挂参初始化 } public void doFilter(ServletRequest servletrequest, ServletResponse servletresponse, FilterChain filterchain) throws IOException, ServletException { HttpServletRequest httpservletrequest = (HttpServletRequest)servletrequest; httpservletrequest.setCharacterEncoding(targetEncoding); System.out.println("使用"+targetEncoding+"对请求进行编码过滤"); filterchain.doFilter(servletrequest, servletresponse); } public void setFilterConfig(FilterConfig filterconfig) { filterConfig = filterconfig; } public void destroy() { filterConfig = null; } } /** * 作用：过滤外界非法的进入页面 * 注意：使用该功能时，一定要把登录页与被过滤文件夹设为同级，否则会出现循环 */ package filter; import java.io.IOException; import javax.servlet.*; import javax.servlet.http.*; public class ManageFilter implements Filter { String LOGIN_PAGE; protected FilterConfig filterConfig; public ManageFilter() { LOGIN_PAGE = "/login.jsp"; } public void doFilter(ServletRequest servletrequest, ServletResponse servletresponse, FilterChain filterchain) throws IOException, ServletException { HttpServletRequest request = (HttpServletRequest) servletrequest; HttpServletResponse response = (HttpServletResponse) servletresponse; HttpSession session = request.getSession(); String key = ""; try { //通过验证时在session中存的一个标志 key = (String) session.getAttribute("key"); if (key!= null&&key.equals("ok")) { filterchain.doFilter(servletrequest, servletresponse); } else { response.sendRedirect(LOGIN_PAGE); System.out.println("被拦截一个未认证的请求"); } } catch (Exception exception) { exception.printStackTrace(); } } public void setFilterConfig(FilterConfig filterconfig) { filterConfig = filterconfig; } public void destroy() { filterConfig = null; } public void init(FilterConfig filterconfig) throws ServletException { filterConfig = filterconfig; } } 2、在web.xml中做一些设置
strawberry79
发表于:2005.02.28 13:35
::分类:
( Struts技术研究
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re: Filter过滤器的使用 
