今天一直想重写DispatchAction的excute方法来判断用户session是否过期，但是由于项目中所有的Action从一开始都是extends DispatchAction，全盘替换总怕出什么问题，所以想换一种方式，考虑在进入具体action前先走过滤器，那么是否可以在过滤器中试一下呢？上网一搜果然可以，先将代码备份一下作将来参考用：
public class SetCharacterEncodingFilter implements Filter {
// ----------------------------------------------------- Instance Variables
/**
* The default character encoding to set for requests that pass through this
* filter.
*/
protected String encoding = null;
/**
* The filter configuration object we are associated with. If this value is
* null, this filter instance is not currently configured.
*/
protected FilterConfig filterConfig = null;
/**
* Should a character encoding specified by the client be ignored?
*/
protected boolean ignore = true;
// --------------------------------------------------------- Public Methods
/**
* Take this filter out of service.
*/
public void destroy() {
this.encoding = null;
this.filterConfig = null;
}
private final static String[] ignore_url={"/index.do"};//进入各子平台时不用坐登录check
/**
* Select and set (if specified) the character encoding to be used to
* interpret request parameters for this request.
*
* @param request
* The servlet request we are processing
* @param result
* The servlet response we are creating
* @param chain
* The filter chain we are processing
*
* @exception IOException
* if an input/output error occurs
* @exception ServletException
* if a servlet error occurs
*/
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
System.out.println("&&&&&&&&&&&&&&&&doFilter&&&&&&&&&&&&&&");
// Conditionally select and set the character encoding to be used
boolean haveFind = true;
if (ignore || (request.getCharacterEncoding() == null)) {
String encoding = selectEncoding(request);
if (encoding != null)
{
request.setCharacterEncoding(encoding);
response.setCharacterEncoding(encoding);
}
}
RequestDispatcher dispatcher = request.getRequestDispatcher("logout.jsp");//这里设置如果没有登陆将要转发到的页面
HttpServletRequest req = (HttpServletRequest) request;
HttpServletResponse res = (HttpServletResponse) response;
HttpSession session = req.getSession(true);
if (req.getRequestURI().indexOf(".jsp") >= 0 || req.getRequestURI().indexOf(".do") >= 0)
haveFind = false;
//System.out.println(haveFind);
for (int i = 0; i < ignore_url.length; i++) {
if (req.getRequestURI().indexOf(ignore_url[i]) >= 0) {
haveFind = true;
break;
}
}
//System.out.println(req.getRequestURI()+haveFind);
// 从session里取的用户名信息
String username = (String) session.getAttribute("Hthm_RealName");//这里获取session，为了检查session里有没有保存用户信息，没有的话回转发到登陆页面
// 判断如果没有取到用户信息,就跳转到登陆页面
if (!haveFind&&(username == null || "".equals(username)))
{
// 跳转到登陆页面
dispatcher.forward(request,response);
System.out.println("用户没有登陆，不允许操作");
res.setHeader("Cache-Control","no-store");
res.setDateHeader("Expires",0);
res.setHeader("Pragma","no-cache");
}
else
{
// 已经登陆,继续此次请求
chain.doFilter(request,response);
// System.out.println("用户已经登陆，允许操作");
}
// Pass control on to the next filter
//chain.doFilter(request, response);
Map map = request.getParameterMap();
Set set = map.entrySet();
if(map!= null)
{
for(Iterator it = set.iterator();it.hasNext();)
{
Map.Entry entry = (Entry) it.next();
if(entry.getValue() instanceof String[])
{
String[] values = (String[]) entry.getValue();
//TransHtmlTag是spring中类文件.
for(int i = 0 ; i < values.length ; i++)
values[i] = TransHtmlTag.TransHtmlTag(values[i]);
entry.setValue(values);
}
}
}
}
/**
* Place this filter into service.
*
* @param filterConfig
* The filter configuration object
*/
public void init(FilterConfig filterConfig) throws ServletException {
this.filterConfig = filterConfig;
this.encoding = filterConfig.getInitParameter("encoding");
String value = filterConfig.getInitParameter("ignore");
if (value == null)
this.ignore = true;
else if (value.equalsIgnoreCase("true"))
this.ignore = true;
else if (value.equalsIgnoreCase("yes"))
this.ignore = true;
else
this.ignore = false;
}
// ------------------------------------------------------ Protected Methods
/**
* Select an appropriate character encoding to be used, based on the
* characteristics of the current request and/or filter initialization
* parameters. If no character encoding should be set, return
* <code>null</code>.
* <p>
* The default implementation unconditionally returns the value configured
* by the <strong>encoding</strong> initialization parameter for this
* filter.
*
* @param request
* The servlet request we are processing
*/
protected String selectEncoding(ServletRequest request) {
return (this.encoding);
}
}// EOC