java用过滤器验证登录框架_jsp实现登录验证的过滤器

本文实例为大家分享了jsp实现登录验证的过滤器，供大家参考，具体内容如下

1.新建一个Dynamic Web Project项目，里面新建1个filter文件、1个servlet文件和2个jsp文件，整体的框架如图所示：

2.LoginFilter.java里面的代码如下所示：

package filter;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.annotation.WebFilter;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

@WebFilter(filterName = "loginFilter", urlPatterns = { "/*" })

public class LoginFilter implements Filter {

public void destroy() {

}

public void doFilter(ServletRequest request, ServletResponse response,

FilterChain chain) throws IOException, ServletException {

HttpServletRequest req = (HttpServletRequest) request;

HttpServletResponse resp = (HttpServletResponse) response;

HttpSession session = req.getSession(true);

resp.setContentType("text/html;");

resp.setCharacterEncoding("utf-8");

PrintWriter out = resp.getWriter();

String request_uri = req.getRequestURI();

String ctxPath = req.getContextPath();

String uri = request_uri.substring(ctxPath.length());

if (uri.contains("login.jsp") || uri.contains("loginServlet")) {

chain.doFilter(request, response);

} else {

if (session.getAttribute("user") != null) {

chain.doFilter(request, response);

} else {

out.println("您没有登录，请先登录！3秒后回到登录页面。");

resp.setHeader("refresh", "3;url=" + ctxPath + "/login.jsp");

return;

}

}

}

public void init(FilterConfig fConfig) throws ServletException {

}

}

3.LoginServlet.java里面的代码如下所示：

package servlet;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

@WebServlet(name = "loginServlet", urlPatterns = { "/loginServlet" })

public class LoginServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

protected void doGet(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

doPost(request, response);

}

protected void doPost(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

String username = request.getParameter("name");

String password = request.getParameter("pwd");

if ("filter".equals(username) && "filter".equals(password)) {

HttpSession session = request.getSession(true);

session.setAttribute("user", username);

response.sendRedirect("loginSuccess.jsp");

} else {

response.sendRedirect("login.jsp");

}

}

}

4.login.jsp里面的代码如下所示：

pageEncoding="UTF-8"%>

5.loginSuccess.jsp里面的代码如下所示：

pageEncoding="UTF-8"%>

String username = (String) session.getAttribute("user");

%>

恭喜登录成功！

6.在浏览器里面输入http://localhost:8080/Servlet/login.jsp运行之后得到的结果如下所示：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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