如何将值从 HTML 页面传递到 Java 小程序?

问题描述：

我尝试过使用如下所示的 javascript 传递值

I have tried passing values using javascript like below

<script language= "javascript" type= "text/javascript">
var num;
function getVal()
{
num=document.getElementById('in').value;
alert(document.getElementById('parm').value);
}
</script>
<body>
<form >
Number : <input type="text" id="in"  ><br/>
<button id="myBtn" onclick="getVal()">Try it</button><br/>  
</form>
<APPLET code="Calc.class" width="100" height="100">
<PARAM name="number" id="parm">
</APPLET>

</body>    
</html>

警告框在屏幕上显示输入的值，但小程序代码显示不一样.我的小程序代码是

The alert box displays the entered value on screen but the applet code is not displaying the same. My applet code is

public class Calc extends Applet
{

    private String strDefault = "Hello! Java Applet.";
    public void paint(Graphics g) {
    String strParameter = this.getParameter("number");
    if (strParameter == null)
    strParameter = strDefault;
    g.drawString(strParameter, 10, 10);
    }
}

谁能告诉我在 param 标签和 html 之间传递和检索值的代码?

Can anyone tell me the code to pass and retrieve values to and from param tag to html?

答

我认为您可以像这样从 javascript 对象指定参数:

I think you can specify your parameters from javascript objects like so:

<applet code="Calc.class" width="100" height="100">
    <param name="number" id="parm" value="&{num};">
</applet>

但是，我不确定与 IE 的兼容性，因此您可能必须document.write 将您的小程序代码注入相应的参数值，如下所示:

However, I'm not sure of the compatibility with IE so you may have to document.write out your applet code injecting the respective parameter values like so:

<head>
    <script type="text/javascript">
        var num;

        function getVal() {
            num = document.getElementById('in').value;

            writeAppletTags();
        }

        function writeAppletTags() { 
            var container = document.getElementById("applet-container");

            container.innerHTML = "<applet code=\"Calc.class\" width=\"100\" height=\"100\">";
            container.innerHTML += "<param name=\"number\" value=\"" + num + "\">";
            container.innerHTML += "</applet>";
        }
    </script> 
</head>
<body>
    Number : <input type="text" id="in"  ><br/>
    <button id="myBtn" onclick="getVal()">Try it</button><br/>  
    <div id="applet-container" />
</body>

从 Java 发送 POST

正如我在评论中所说，这有点复杂.您必须将值发布到托管文件(可以是任何服务器端脚本技术)(您也可以使用 GET).下面演示了这一点，从这里获取的代码一>.

As I said in my comment, this is a little more complicated. You'd have to POST (you could also use GET) your values to a hosted file (can be any server side scripting technology). The following demonstrates this, code taken from here.

URL url;
URLConnection urlConnection;
DataOutputStream outStream;
DataInputStream inStream;

// Build request body
String body = "key=value";

// Create connection
url = new URL("http://myhostedurl.com/receiving-page.php");
urlConnection = url.openConnection();
((HttpURLConnection)urlConnection).setRequestMethod("POST");
urlConnection.setDoInput(true);
urlConnection.setDoOutput(true);
urlConnection.setUseCaches(false);
urlConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
urlConnection.setRequestProperty("Content-Length", ""+ body.length());

// Create I/O streams
outStream = new DataOutputStream(urlConnection.getOutputStream());
inStream = new DataInputStream(urlConnection.getInputStream());

// Send request
outStream.writeBytes(body);
outStream.flush();
outStream.close();

// Close I/O streams
inStream.close();
outStream.close();

如何将值从 HTML 页面传递到 Java 小程序?

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