springmvc提供了拦截器，类似于过滤器，他将在我们的请求具体出来之前先做检查，有权决定接下来是否继续，对我们的请求进行加工。
AccessFilter.java
import java.io.IOException;
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.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class AccessFilter implements Filter {
@Override
public void destroy() {
// TODO Auto-generated method stub
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
HttpServletResponse res = (HttpServletResponse) response;
HttpServletRequest req = (HttpServletRequest) request;
String path = req.getRequestURI();
System.out.println(path);
if (path.endsWith("login.html") || path.endsWith("register.html")) {
chain.doFilter(request, response);
return;
}
HttpSession session = req.getSession();
Object id = session.getAttribute("id");
if (id == null) {
// System.out.println("用户没有登录");
String contextPath = req.getContextPath();
// System.out.println("contextPath:"+contextPath);
res.sendRedirect(contextPath + "/login.html");
return;
}
chain.doFilter(request, response);
}
@Override
public void init(FilterConfig arg0) throws ServletException {
// TODO Auto-generated method stub
}
}
