查看：案例11

1 web层LoginServlet修改

package www.test.web.servlet;

import java.io.IOException;
import java.net.URLEncoder;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import www.test.domain.User;
import www.test.service.LoginService;

public class LoginServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// 解决乱码问题
request.setCharacterEncoding("UTF-8");
HttpSession session = request.getSession();

// 获得页面输入的验证
String checkCode_client = request.getParameter("checkCode");
// 获得生成图片的文字的验证码
String checkCode_session = (String) request.getSession().getAttribute("checkcode_session");
// 比对页面的和生成图片的文字的验证码是否一致
if (!checkCode_session.equals(checkCode_client)) {
request.setAttribute("loginInfo", "您的验证码不正确");
request.getRequestDispatcher("/login.jsp").forward(request, response);
return;
}
// 获取用户输入的数据
String username = request.getParameter("username"); //中文名 张三
String password = request.getParameter("password");

LoginService service = new LoginService();
User user = null;
try {
user = service.login(username, password);
} catch (SQLException e) {

e.printStackTrace();
}

if (user != null) {
// 登录成功
// 判断用户是否勾选自动登录
String autoLogin = request.getParameter("autoLogin");
if (autoLogin != null) {
//对中文张三进行编码
String username_code = URLEncoder.encode(username, "UTF-8");// %AE4%kfj

Cookie cookie_username = new Cookie("cookie_username", username_code);
Cookie cookie_password = new Cookie("cookie_password", user.getPassword());
// 设置 cookie 的持久化时间
cookie_username.setMaxAge(60 * 60);
cookie_password.setMaxAge(60 * 60);
// 设置 cookie 的携带路径
cookie_username.setPath(request.getContextPath());
cookie_password.setPath(request.getContextPath());
// 发送 cookie
response.addCookie(cookie_username);
response.addCookie(cookie_password);
}
//将登录的用户的 user 对象存到 session 中
session.setAttribute("user", user);
//重定向到首页
response.sendRedirect(request.getContextPath());

} else {
request.setAttribute("loginInfo", "密码或者用户名不正确");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
}

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}

2 web层AutoLoginFilter

package www.test.web.filter;

import java.io.IOException;
import java.net.URLDecoder;
import java.sql.SQLException;

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.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import www.test.domain.User;
import www.test.service.LoginService;

public class AutoLoginFilter implements Filter {

public AutoLoginFilter() {
super();
}

private FilterConfig filterConfig;

public void init(FilterConfig filterConfig) throws ServletException {

this.filterConfig = filterConfig;

}

public void doFilter(ServletRequest req, ServletResponse res, FilterChain filterChain)
throws IOException, ServletException {

HttpServletRequest request = (HttpServletRequest) req;

HttpServletResponse response = (HttpServletResponse) res;

HttpSession session = request.getSession();

// 获得 cookie 中用户名和密码 进行登录的操作
// 定义 cookie_username
String cookie_username = null;
// 定义 cookie_password
String cookie_password = null;
// 获得 cookie
Cookie[] cookies = request.getCookies();
if (cookies != null) {
for (Cookie cookie : cookies) {// 获得名字是 cookie_username 和
// cookie_password
if ("cookie_username".equals(cookie.getName())) {
cookie_username = cookie.getValue();
//恢复中文用户名
cookie_username = URLDecoder.decode(cookie_username, "UTF-8");
}
if ("cookie_password".equals(cookie.getName())) {
cookie_password = cookie.getValue();
}
}
}
// 判断 username 和 password 是否是 null
if (cookie_username != null && cookie_password != null) {
// 登录的代码
LoginService service = new LoginService();

User user = null;
try {
user = service.login(cookie_username, cookie_password);
} catch (SQLException e) {
e.printStackTrace();
}
// 将登录的用户的 user 对象存到 session 中
session.setAttribute("user", user);
}

//放行
filterChain.doFilter(request, response);
}

public void destroy() {

}
}