Javascript 如何将值从 HTML 页面传递到 Java 小程序？
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How to pass values from HTML page to java applet?
提问by prgmrDev
I have tried passing values using javascript like below
我曾尝试使用 javascript 传递值，如下所示
<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>
The alert box displays the entered value on screen but the applet code is not displaying the same. My applet code is
警报框在屏幕上显示输入的值，但小程序代码显示不同。我的小程序代码是
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);
}
}
Can anyone tell me the code to pass and retrieve values to and from param tag to html?
谁能告诉我在 param 标签和 html 之间传递和检索值的代码？
回答by Paul Aldred-Bann
I think you can specify your parameters from javascript objects like so:
我认为您可以从 javascript 对象中指定参数，如下所示：
<applet code="Calc.class" width="100" height="100">
<param name="number" id="parm" value="&{num};">
</applet>
However, I'm not sure of the compatibility with IE so you may have to document.writeout your applet code injecting the respective parameter values like so:
但是，我不确定与 IE 的兼容性，因此您可能必须document.write删除注入相应参数值的小程序代码，如下所示：
<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>
Sending POST from Java
从 Java 发送 POST
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.
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，代码取自此处。
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();
回答by Khanh Tran
Source from this article
来自这篇文章
For example: This is your applet codes:
例如：这是您的小程序代码：
import java.applet.*;
import java.awt.*;
public class DrawStringApplet extends Applet {
private String defaultMessage = "Hello!";
public void paint(Graphics g) {
String inputFromPage = this.getParameter("Message");
if (inputFromPage == null) inputFromPage = defaultMessage;
g.drawString(inputFromPage, 50, 25);
}
}
Then in HTML:
然后在 HTML 中：
<HTML>
<HEAD>
<TITLE> Draw String </TITLE>
</HEAD>
<BODY>
This is the applet:<P>
<APPLET code="DrawStringApplet" width="300" height="50">
<PARAM name="Message" value="Howdy, there!">
This page will be very boring if your
browser doesn't understand Java.
</APPLET>
</BODY>
</HTML>
Notice:DrawStringApplet is you applet name; Message is a parameter sent to applet; Applet will then display: Howdy, there!as a result.
注意：DrawStringApplet 是您的小程序名称；消息是发送给小程序的参数；然后小程序将显示：Howdy, there!结果。
