servlet中 跳转到jsp界面 不能跳转 也没有任何报错

Question

在servlet中不能跳转界面 我测试过deBUG,能够一直到代码request.getRequestDispatcher("/Exchange/JSP/main.jsp").forward(request, response);这里 可就是不能跳到界面去，还没有任何提示
public class accError extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
// response.setContentType("text/html;charset=utf-8");
accPasCheck apcheck = new accPasCheck();// 帐号密码检测类
PrintWriter out = response.getWriter();

    // 得到客户端的帐号和密码
    String account = request.getParameter("account");
    String password = request.getParameter("password");

    // 帐号密码正确验证
    if (apcheck.exit(account, password)) {
        // 帐号密码正确
        // out.print("yes");
        request.getRequestDispatcher("/Exchange/JSP/main.jsp").forward(
                request, response);
    }