Filter的使用
要自己创建一个URL过滤的Filter，必须继承HttpServlet和实现Filter接口。
HttpServlet是javax.servlet.http.HttpServlet的类;
Filter是javax.servlet.Filter的接口;
public class RoleFilter extends HttpServlet implements Filter {
private String msg = "";
public boolean test(int node) {
// TODO Auto-generated method stub
return false;
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
// TODO Auto-generated method stub
HttpServletResponse httpServletResponse = (HttpServletResponse) response;
HttpServletRequest httpServletRequest = (HttpServletRequest) request;
String url = httpServletRequest.getRequestURI();
System.out.println(url);
if (url.equals("/roleDemo/")) {
chain.doFilter(httpServletRequest, httpServletResponse);
} else if (url.endsWith(".jsp")) {
httpServletRequest.setAttribute("msg", msg);
chain.doFilter(httpServletRequest, httpServletResponse);
} else {
httpServletResponse.setCharacterEncoding("GB2312");
httpServletRequest.setCharacterEncoding("GB2312");
msg = "你没有登录！";
httpServletResponse.sendRedirect(httpServletRequest
.getContextPath()
+ "/error.jsp");
}
}
public void init(FilterConfig filterConfig) throws ServletException {
// TODO Auto-generated method stub
}