利用java servlet實現簡單的web請求過濾和跳轉

今日有兩個微信web項目合並了，但是還有些鏈接指向廢棄的項目，另外不想在服務器上運行兩份相同web項目(1、影響性能、2、維護升級容易出錯)，因此決定寫一個簡單鏈接跳轉的項目，spring的filter過濾器可以實現，但想想spring干這個有點大材小用，想到java的servlet可以支持通配符，因此用servlet寫了一個簡單的跳轉程序，總共花了不到一小時的時間。廢話少說上代碼：

/**
 * Servlet implementation class Default
 */
@WebServlet("/*")
public class Default extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Default() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        String thisURI = request.getRequestURL().toString();
        String queryString = request.getQueryString();
        String host = "112.125.121.163";
        //String host = "localhost";
        String oldURI = "http://" + host + ":8080/travel-core";
        if (thisURI.indexOf(oldURI) >= 0) {
            String newURI = thisURI.replaceAll(oldURI, "http://" + host
                    + ":8080/travel-weixin");
            if (queryString != null && queryString.length() > 0)
                newURI += "?" + queryString;
            response.sendRedirect(newURI);
        }
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }

}

注意代碼第四行是關鍵@WebServlet("/*")，這里使用了通配符，所有的請求都會送到doGet和doPost方法里，另外要注意 request.getRequestURL()方法不能獲取到queryString因此一定要request.getQueryString()獲取參數，拼到新地址的后面。