呼叫通过JavaScript Java小程序的方法 [英] Call a java applet method via javascript

问题描述

我怎么能调用一个函数，当一个特定的事件在我的Java小程序出现？

How can I call a function when a specific event occurs in my java Applet ?

在我的javascript我有以下code，总是返回空值。

In my Javascript I has the following code, that always return a empty value.

$(function () {
    alert(document.applets[0].returnClientId());
});

我需要调用此警报，只是当执行一个特定的方法。更具体地，称为识别方法，存在于我的Java小程序

I need to call this alert, just when a specific method is executed. To be more specific, the method called identify, that exists in my java Applet.

的识别方法，存在于我的Util.class，即不要从JApplet的延伸。
我FormMain.class从JApplet的延伸，我称之为从这个Util.class一些方法（包括识别方法）。

The identify method, exists in my Util.class, that don't extends from JApplet. My FormMain.class extends from JApplet and I call some methods (including the identify method) from this Util.class.

更新：我的Java code

UPDATE: My Java Code

public String getClientid() {
    return clientid;
}

public void setClientid(String clientid) {
    this.clientid = clientid;
}

public String returnClientId() {
    return getClientid();
}

public void identify() {
    try {
        fingerprintSDK.prepareForIdentification(this.template);

        ResultSet rs = identifyStmt.executeQuery();

        while (rs.next()) {         
            byte[] templateBuffer = rs.getBytes("template");

            Template referenceTemplate = new Template(templateBuffer);

            boolean matched = fingerprintSDK.identify(referenceTemplate);

            if (matched) {
            // ui is my FormMain instance
                ui.showImage(GrFingerJava.getBiometricImage(template,
                        fingerprint, fingerprintSDK));

                ui.writeLog("Found. Client = "
                        + rs.getString("Name"));

                ui.setClienteid(rs.getString("Cliente_Id"));

                ui.disableTemplate();                   
                return;
            }
        }

        ui.writeLog("Not Found.");
        ui.enableTemplate();
    } catch (SQLException e) {

        ui.writeLog(e.getMessage());
    } catch (GrFingerJavaException e) {
        ui.writeLog(e.getMessage());
    }
}

在我的用户把手指在生物识别设备是刚刚执行的鉴定方法。

The Identify method is executed just when my User put the finger in the biometric device.

有人有一些想法？

推荐答案

假设你有以下的JS函数

Suppose you have the following JS function

function foo(client) {
    alert(client);
}

您会修改 Utils.java 如下：

public void identify() {
    // the rest of your code
    String id = rs.getString("Cliente_Id");
    ui.setClienteid(id);
    // call the Javascript function
    JSObject.getWindow(ui).eval(String.format("foo(%s)", id));
}

• 从applet的Javascript调用code


• Java来的Javascript通信（Oracle官方文档）


• Invoking Javascript code from an Applet
• Java to Javascript communication (Official Oracle docs)

要使用编译code netscape.javascript。* 包您需要的 $ JAVA_HOME / JRE / lib目录/ plugin.jar 。 看到这里

To compile the code using netscape.javascript.* package you need the $JAVA_HOME/jre/lib/plugin.jar. See here

为了调用JavaScript，Java的code使用
  netscape.javascript.JSObject和netscape.javascript.JSException
  类。由于Java 2的发布，标准版1.4版，
  在JAR文件中的jre / lib中提供了这些类/ plugin.jar内
  无论是Java开发工具和Java运行时环境。如果你
  引用这些JavaScript类，您将需要plugin.jar增加
  你的编译类路径。这可以通过你的Java IDE来完成，如果
  您可以使用一个，或者通过-classpath命令行参数
  Java编译器javac的。

In order to call JavaScript, Java code uses the netscape.javascript.JSObject and netscape.javascript.JSException classes. Since the release of Java 2, Standard Edition version 1.4, these classes are provided in the jar file jre/lib/plugin.jar within either the Java Development Kit or Java Runtime Environment. If you reference these JavaScript classes, you will need to add plugin.jar to your compilation classpath. This can be done through your Java IDE, if you use one, or by passing the -classpath command-line argument to the Java compiler javac.

在运行时，Java插件会自动使这些类
  适用于小程序，所以没有给小程序改变或它是如何设置
  是必要的。

At run-time, the Java Plug-In automatically makes these classes available to applets, so no changes to the applet or how it is set up are necessary.

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