jsp : 我可以更改 render/execution 的顺序吗

Question

我正在研究 jsp，我要实现的很简单。

用Java
在处理时，向用户显示微调器

所以我实现如下

<%@ page contentType="text/html; charset=UTF-8" %>
<%@ page isThreadSafe="true" %>
<%

    boolean isFinish = false;
    Thread executeThread = new Thread(new Runnable() {
        @Override
        public void run() {
            for(int i = 0; i < 10; i++){
                try{
                    System.out.println(i + " Thread ");
                    Thread.sleep(1000);
                }catch(Exception ex){
                    System.err.println(ex);
                }
            }
        }
    });

    executeThread.run();
%>
<!DOCTYPE html>
<html>
    <head>
        <meta charset='utf-8'>
        <title>Loading</title>
    </head>
    <body>
        <div class="popup" style="text-align: center;">
            <div class="l_img">
                <img src="resources/image/spinner/loading_gif.gif" alt="LOADING...">
            </div>
            <div class="b_txt">Processing</div>
            <div class="s_txt">Please, wait..</div>
        </div>
    </body>
    <%
        if(isFinish){
    %>
        <script>
            alert('done');
        </script>
    <%
        }
    %>
</html>

但是，页面会在 Thread 终止后显示。我可以颠倒顺序吗？我想要的顺序

显示html页(spinner gif)
执行Java逻辑
捕获Java执行的return
如果 return 是 true，则用 javascript

可能吗？感谢您的回答

Answer 1

您无法通过服务器端操作动态更改页面呈现。

页面将始终在 if(isFinish) 已执行的位置呈现。

只有当所有的java都执行完并且在一个块中时，服务器才会将完整的html页面发送给用户！你需要在前端实现它，例如你发送一个开始加载的基本页面，然后你用 ajax 调用或类似的东西调用长期过程。

Answer 2

<!DOCTYPE html>
<html>
<body onload="alert('done')">
    Put your spinner here.
    Some text here is necessary here for the browser to start displaying. 
    Otherwise it will wait until it receives enough of a response to begin displaying anything. 
    I am not sure how much is necessary. This works for me.
<%
    out.print("<br/>Starting processing now. <br/>");
    out.flush();
    Thread.sleep(2000);
    out.print("<br/>Processing..... <br/>");
    out.flush();
    for(int x = 1; x < 4; x++){
        Thread.sleep(2000); 
        out.print("Result " + x + ".<br/>"); 
        out.flush();
    }
%>
</body>
</html>

jsp : 我可以更改 render/execution 的顺序吗

jsp : Could I change the order of render/execution

javascript

jsp

spinner

java-threads