Calling external javascript function from java

Question

I have tried to call javascript function from java code, but I am getting the following error while using javascript API:

Caused by: sun.org.mozilla.javascript.internal.EcmaError: ReferenceError: "File" is not defined. (#8) at sun.org.mozilla.javascript.internal.ScriptRuntime.constructError(ScriptRuntime.java:3770) at sun.org.mozilla.javascript.internal.ScriptRuntime.constructError(ScriptRuntime.java:3748) at sun.org.mozilla.javascript.internal.ScriptRuntime.notFoundError(ScriptRuntime.java:3833) at sun.org.mozilla.javascript.internal.ScriptRuntime.name(ScriptRuntime.java:1760) at sun.org.mozilla.javascript.internal.Interpreter.interpretLoop(Interpreter.java:1785) at sun.org.mozilla.javascript.internal.Interpreter.interpret(Interpreter.java:849)

java code:

    ScriptEngineManager manager = new ScriptEngineManager();
    ScriptEngine engine = manager.getEngineByName("JavaScript");

    engine.eval(Files.newBufferedReader(Paths.get("D:/test/test.js"), StandardCharsets.UTF_8));
    Invocable inv = (Invocable) engine;

    inv.invokeFunction("display", "test");
    inv.invokeFunction("writeTextFile", "D:\\test\\file.txt", "test");

test.js:

var display = function(name) {
    print("Hello, I am a Javascript display function "+name);
    return "display function return"
}

function writeTextFile(afilename, output) {
    var txtFile = new File(afilename);
    txtFile.writeln(output);
    txtFile.close();
}

display function working fine, the error appear while executing writeTextFile function.

Possible duplicate of Call external javascript functions from java code — dganenco
– dganenco, Commented Aug 5, 2019 at 14:10
Seems like it is due to wrong arguments passed for new File() in the test.js. I think the following would help you get it resolved:stackoverflow.com/a/26181292/3981539 — Kavitha Karunakaran
– Kavitha Karunakaran, Commented Aug 5, 2019 at 14:12
Hi, I tried the same but same error appears. I seems my missing is the JavaScript libraries as File can't be defined well. But I don't know how to import javaScript lib to java. — user8058941
– user8058941, Commented Aug 5, 2019 at 14:45

AlexC · Accepted Answer · 2019-08-05 14:14:38Z

0

in your test.js, try:

var txtFile = new File([""], afilename);

answered Aug 5, 2019 at 14:14

AlexC

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3 Comments

user8058941 Over a year ago

Hi, same error. I seems my missing is the JavaScript libraries as File can't be defined well.

AlexC Over a year ago

I don't think you will be able to write a file to the local filesystem using javascript called via script engine. See w3c.github.io/FileAPI for more info (and comments about restrictions and compatibility). And also discussion at stackoverflow.com/questions/461791/… This is essentially a huge security hole, if you execute a script in your java app and someone replaces it with malicious that writes to user disk without approval. Most browsers don't allow you to write to user's disk.

AlexC Over a year ago

As a work around, call "display", get result and then use Java to create the file for you instead of JavaScript.

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