JavaWeb的Filter中获取当前项目物理路径

1.在init方法中获取

	public void init(FilterConfig arg0) throws ServletException {
		arg0.getServletContext().getRealPath("/");
	}

2.在doFilter方法中获取

	public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain){
		((HttpServletRequest) request).getSession().getServletContext().getRealPath("/");
	}