本文執行個體講述了JSP使用Servlet過濾器進行身分識別驗證的方法。分享給大家供大家參考，具體如下：
1、Servlet過濾器的作用描述
（1）在HttpServletRequest到達Servlet 之前，攔截客戶的HttpServletRequest。
根據需要檢查HttpServletRequest，也可以修改HttpServletRequest頭和資料。
（2）在HttpServletResponse 到達用戶端之前，攔截HttpServletResponse。
根據需要檢查HttpServletResponse，可以修改HttpServletResponse頭和資料。
2、應用Servlet過濾器進行身分識別驗證
假設網站根目錄下的login1.htm、longin1.jsp用於使用者登入，而chap08目錄下的檔案需要使用者登入後才能訪問。
（1）編寫Servlet過濾器
@WebFilter("/FilterStation")public class FilterStation extends HttpServlet implements Filter {private FilterConfig filterConfig;public FilterStation() {super();}public void destroy() {}public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {HttpSession session=((HttpServletRequest)request).getSession();response.setCharacterEncoding("gb2312");if(session.getAttribute("me")==null){PrintWriter out=response.getWriter();out.print("<script>alert('請登入！');location.href='../login1.htm'</script>");}else{// pass the request along the filter chainchain.doFilter(request, response);}}public void init(FilterConfig fConfig) throws ServletException {// TODO Auto-generated method stubthis.filterConfig=fConfig;}}
（2）配置web.xml
<filter><filter-name>filterstation</filter-name><filter-class>zhou.FilterStation</filter-class></filter><filter-mapping><filter-name>filterstation</filter-name><url-pattern>/chap08/*</url-pattern></filter-mapping>
（3）login1.htm代碼
<html><head><title>使用者登入</title></head><body><form method="POST" action="login1.jsp"><p>使用者名稱：<input type="text" name="user" size="18"></p><p>密碼：<input type="text" name="pass" size="20"></p><p><input type="submit" value="提交" name="ok"><input type="reset" value="重設" name="cancel"></p></form></body></html>
（4）login1.jsp代碼
<%@ page contentType="text/html;charset=GB2312" %><html><head><title>Session 應用示範</title></head><% if (request.getParameter("user")!=null && request.getParameter("pass")!=null){String strName=request.getParameter("user");String strPass=request.getParameter("pass");if (strName.equals("admin") && strPass.equals("admin")){session.setAttribute("login","OK");session.setAttribute("me",strName);response.sendRedirect("chap08/welcome.jsp");}else{out.print("<script>alert('使用者名稱或密碼錯誤');location.href='login1.htm'</script>");}}%></html>
希望本文所述對大家JSP程式設計有所協助。
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