web.xml配置
<filter>
<filter-name>LoginFilter</filter-name>
//編寫攔截的類的全類名
<filter-class>cn.books.filter.LoginFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>LoginFilter</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>
LoginFilter類
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
/*攔截jsp頁面*/
// TODO Auto-generated method stub
HttpServletRequest request1=(HttpServletRequest) request;
String currentURL=request1.getRequestURI();
String ctxPath=request1.getContextPath();
//targerURl是路徑
String targetURL=currentURL.substring(ctxPath.length());
HttpSession sessionuser = request1.getSession();
//取到你存入httpsession中的數據
String user = (String) sessionuser.getAttribute("usersession");
//判斷路徑是否是/login.jsp或者/register.jsp如果是則放行繼續執行
if(("/login.jsp").equals(targetURL)||("/register.jsp").equals(targetURL)) {
chain.doFilter(request, response);
}else if(!(user==null)){//判斷用戶是否登錄
chain.doFilter(request, response);
}else if(("/").equals(targetURL)){//判斷是否是第一次默認跳轉頁面
chain.doFilter(request, response);
}else {//如果以上情況都不是則跳回登錄界面
((HttpServletResponse) response).sendRedirect("/books/login.jsp");
}