如何从一个Java类传递一个变量的值到JSP页面 [英] How to pass a value of a variable from a java class to the jsp page

问题描述

我有一个名为2个文件 Admin.java 和的index.jsp 。

I have 2 files named Admin.java and index.jsp.

在 Admin.java 通过函数我取回了名为 RES 的varible的价值。这个变量需要传递到JSP页面。

In Admin.java through a function I retrieve the value of the varible named res. This variable needs to be passed to a JSP page.

在 Admin.java 是 C：\ Users \用户普利文\工作区\ SemanticWeb的\ src \控制器而在的index.jsp 是 C：\ Users \用户普利文\工作区\ SemanticWeb \的WebContent

的code Admin.java 是：

public Admin() 
{
  super();
}       

  protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException 
 {

    if (action.equals("login")) 
    {
        String userName="";
        String password="";

        userName = request.getParameter("username");
        password = request.getParameter("password");

        response.setCharacterEncoding("UTF-8");

        SemanticSearch semsearch = new SemanticSearch(request.getSession());
        semsearch.loadData(REALPATH + RDFDATASOURCEFILE1);

        String res=semsearch.searchForUser(userName, password);
        System.out.println("The value of res been passed is "+res);

        request.setAttribute("rest", res);

        return;
     }

的code 的index.jsp 是

function login(user, pass) 
{

  $.ajax({
    type:"GET",
    url: "Admin?action=login",
    dataType: "text",
    data: { username: user, password: pass },
    success: function(response){

    }

在

function(response)
{
 ......
} 

我需要访问的 RES 按 Admin.java通过的值。我不能得到任何适当的帮助，我在互联网上code。请有人可以帮我这个。

I need to access the value of res passed by Admin.java. I am not able to get any proper help for my code on the Internet. Please can someone help me with this.

推荐答案

从code，

request.setAttribute("rest", res);

您不应该将它设置为请求属性。如果你转发到JSP文件设置请求属性才有用。你需要将它写入直接到自己的反应。通过

You shouldn't set it as request attribute. Setting request attributes is only useful if you're forwarding to a JSP file. You need to write it straight to the response yourself. Replace the line by

response.getWriter().write(res);

此方式，它最终会在响应正文和可作为变量响应在你的JS函数。

This way it'll end up in the response body and be available as variable response in your JS function.

• 如何通过的Servlet / Ajax来更新当前页面？

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