Java 防盗链 Referer

public class HTTPWebAuthFilter implements Filter {

	@Autowired
	private CommonConfig commonConfig;
	
	@Autowired
	private HttpSession session;
	
	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		SpringBeanAutowiringSupport.processInjectionBasedOnServletContext(this,
				filterConfig.getServletContext());

	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {

		HttpServletRequest httpRequest = (HttpServletRequest) request;
		
		// 防盗链
		String refer = httpRequest.getHeader("Referer");
		if(!WebTool1.isNull(refer)
				&& refer.indexOf(commonConfig.getLocalServerName()) < 0){

        	String str = "<script language='javascript'>alert('您的违规操作将被中止、记录并保留追溯权利！');"
                    + "window.top.location.href='"
                    + httpRequest.getContextPath()+"/bi/init"
                    + "';</script>";
        	response.setContentType("text/html;charset=UTF-8");// 解决中文乱码
            PrintWriter writer = response.getWriter();
            try {
                writer.write(str);
                writer.flush();
                writer.close();
            } catch (Exception e) {
                e.printStackTrace();
            }finally{
            	writer.close();
            }
            return;
        
		}
		
		if(httpRequest.getRequestURI().endsWith("/login") ){
			if(WebTool1.isNull(session.getAttribute(commonConfig.getAccHeader()))){
				chain.doFilter(request, response);
			}else{
				
				if(!WebTool1.isNull(httpRequest.getParameterMap().get("account"))
						&& httpRequest.getParameterMap().get("account").length > 0){
					chain.doFilter(request, response);
				}else{
					request.setAttribute("roleModels", session.getAttribute("roleModels"));
					request.setAttribute("username", session.getAttribute("username"));
					request.getRequestDispatcher("/WEB-INF/jsp/welcome.jsp").forward(request, response);
					return;
				}
			}
		}else{
			chain.doFilter(request, response);
		}
	}

	@Override
	public void destroy() {
	}
}