JSP：转发页面时出错

Question

这个问题与上一个问题相关，当我单击一个锚点时，

<a href="#" id="Email">send email</a>

它会使用servlet中的json调用servlet

   $("#Email").click(function() {

    var option={
        "action":"sendEmail"
    };
    $.getJSON('StudentManagementServlet',option, function(hasEmail) {
        if(hasEmail == false){
            // //view form to let user enter his email
            $("#CommViaEmail").fadeIn("normal");   
        }
    });
});

我处理请求

 if (action != null && action.equals("sendEmail")) {

    //open connection to db
    con.setAutoCommit(false);
    String email = ParentManagement.getParentEmail(con, stdNo);
    if (email != null) {
        String commResult = createAccountAndSendEmail(con, parentNo, email);
        request.setAttribute("result", commResult);
        request.setAttribute("incp", "ResultPage");
         RequestDispatcher dispatcher = request.getRequestDispatcher("/index.jsp");
        dispatcher.forward(request, response);  //doesn't make forward!!!!!
        System.out.println(">>send email DONE!!");
        con.commit();
        return;
    } else {
        boolean hasEmail = false;
        String json = new Gson().toJson(hasEmail);
        response.setContentType("application/json");
        response.setCharacterEncoding("UTF-8");
        response.getWriter().write(json);

    }
}

这里的问题是如果用户有电子邮件，那么我发送一封电子邮件但请求不会转发到结果页面，甚至打印语句也被打印为“ System.out.println(">>send email DONE!!");" ??

Answer 1

你需要让 JS/jQuery 来完成这项工作。让servlet将true写入JSON结果并在JS中执行

if (hasEmail) {
    window.location = 'index.jsp';
} else {
    $("#CommViaEmail").fadeIn("normal");   //view form to let user enter his email
}

或者当您想自己控制URL时，将新位置添加到JSON

Map<String, Object> data = new HashMap<String, Object>();
data.put("hasEmail", true);
data.put("location", "index.jsp");
// ...

中

..., function(data) {
    if (data.hasEmail) {
        window.location = data.location;
    } else {
        $("#CommViaEmail").fadeIn("normal");   //view form to let user enter his email
    }
}

Answer 2

您正在从客户端发出 AJAX 请求，并尝试在服务器端“转发”该请求。

AJAX 请求不要刷新页面。 javascript 函数 中的hasEmail 变量将是一个包含index.jsp 的HTML 的字符串。