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我想使用 Java 对象new Train()作为参数传递给 JavaScript 函数，这里是 Java 代码

public void execute() {

        File script = new File("/Test.js");

        ScriptEngine engine = new ScriptEngineManager().getEngineByName("graal.js");

        try {
            engine.eval(new FileReader(script));
            Invocable invocable = (Invocable)engine;
            
            Object result = invocable.invokeFunction("fun1", new Train());
            System.out.println(result);
        } catch(Exception e) {
            e.printStackTrace();
        }

}

public class Train {

     private double speed = 0.0D;
     
     public Train() {
          this.speed = 10.5D;
     }

     public double getSpeed() {
          return this.speed;
     }
}

JavaScript 代码

var fun1 = function test(train) {
    print(train.getSpeed());
    return train.getSpeed();
}

截至目前，它将此错误放在控制台中

[16:56:42] [INFO]: [STDERR]: javax.script.ScriptException: org.graalvm.polyglot.PolyglotException: TypeError: invokeMember (getSpeed) on ScriptExecutor$Train@429b2a7b failed due to: Unknown identifier: getSpeed [16:56:42] [INFO]: [STDERR]: at com.oracle.truffle.js.scriptengine.GraalJSScriptEngine.toScriptException(GraalJSScriptEngine.java:483) [16:56:42] [INFO]: [STDERR]: at com.oracle.truffle.js.scriptengine.GraalJSScriptEngine.invokeFunction(GraalJSScriptEngine.java:558)

有什么办法可以使这项工作？

4

1 回答 1

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GraalJS（和一般的 GraalVM）默认具有严格的安全/访问控制。GraalJS 不会将实例getSpeed()上的（或任何其他字段或方法）暴露Train给 JavaScript。

您可以使用配置设置打开对所有主机字段/方法的访问：

Bindings bindings = engine.getBindings(ScriptContext.ENGINE_SCOPE);
bindings.put("polyglot.js.allowHostAccess", true);

getSpeed()或者通过装饰在更细粒度的级别上启用它Train：

import org.graalvm.polyglot.HostAccess;
// ...
@HostAccess.Export
public double getSpeed() {
    return this.speed;
}
于 2022-01-13T01:54:57.653 回答