filter的问题?求指教
这是SetFilter.java代码:
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
request.setCharacterEncoding("gbk");
response.setContentType("text/html;charset=gbk");
HttpServletRequest request2 = (HttpServletRequest) request;
HttpServletResponse response2 = (HttpServletResponse) response;
HttpSession session = request2.getSession(true);
String username = (String) session.getAttribute("username");
if (username == "") {
response2.sendRedirect("login.jsp");
}
chain.doFilter(request, response);
}
这是web.xml代码:
<filter>
<filter-name>SetFilter</filter-name>
<filter-class>
com.bbs.filter.SetFilter
</filter-class>
</filter>
<filter-mapping>
<filter-name>SetFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
为什么过滤器不起作用呀?