Javafx webEngine executescript() cant send multiline string

Question

Problem: I cant seem to find a way for javafx webengine to fire javascript function if I use a java String object with multiple line.

If I enter the following example in html: "asd" ENTER "qwe" in the input textArea then CLICK send button. The following java code wont run:

webEngine.executeScript("onRecieveMsg('" + msg + "')"); .

But it will work if I don't use ENTER in input textArea .

Please help me

 <!DOCTYPE html> <html> <head> <meta charset="ISO-8859-1"> <title>Chat</title> </head> <script type="text/javascript"> function onSendMsg(){ var msg = document.getElementById("inputTextArea").value; document.getElementById("inputTextArea").value = ""; java.onSendMsg(msg); } function onRecieveMsg(msg){ var msg = msg; msg = document.getElementById("outputTextArea").value + msg; document.getElementById("outputTextArea").value = msg + "\\n"; } </script> <body> <h1>Output</h1> <textarea id="outputTextArea" rows="10" cols="50" readonly></textarea> <h1>Input</h1> <textarea id="inputTextArea" rows="4" cols="50"></textarea> <button id="sendBtn" onclick="onSendMsg()">Send</button> </body> </html>

import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.concurrent.Worker.State;
import javafx.scene.Scene;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import javafx.stage.Stage;
import netscape.javascript.JSObject;


public class ViewFx extends Application {

//VARIABLES
private WebView webView;
private WebEngine webEngine; 
private WebEngineListener webEngineListener;
private JsBridge jsBridge;

//CONTRUCTOR

//METHODS
@Override
public void start(Stage stage) {
    webView = new WebView();
    webEngine = webView.getEngine();
    webEngine.load(getClass().getResource("view.html").toExternalForm());
    jsBridge = new JsBridge();
    webEngineListener = new WebEngineListener(jsBridge);
    webEngine.getLoadWorker().stateProperty().addListener(webEngineListener);

    stage.setScene(new Scene(webView));
    stage.setWidth(600);
    stage.setHeight(700);
    stage.show();
}

//INNER CLASS
private class WebEngineListener implements ChangeListener<State> {
    //VARIABLES
    private JsBridge jsBridge;
    private JSObject jsobj;

    //CONSTRUCTOR
    private WebEngineListener(JsBridge jsBridge) {
        this.jsBridge = jsBridge;
    }

    //METHODS
    @Override
    public void changed(ObservableValue<? extends State> observable, State oldState, State newState) {
        if(newState == State.SUCCEEDED) {
            jsobj = (JSObject) webEngine.executeScript("window");
            jsobj.setMember("java", jsBridge);
        }
    }
}

public class JsBridge {
    //VARIABLES

    //CONTRUCTOR

    //METHODS
    public void onSendMsg(String msg) {
        webEngine.executeScript("onRecieveMsg('" + msg + "')");
    }
}

public static void main(String[] args) {
    launch(args);
}

}

Answer 1

Multiline string literals neither work in JavaScript nor in java. In case of a multiline message being received you simply execute invalid JavaScript code:

message received

asd
qwe

Executed javascript

onRecieveMsg('asd
qwe')

You need to escape newline instead of including them in the script. There are a few more characters that require being quoted. You could use a method like this to get a properly quoted string:

public static String toJavaScriptString(String value) {
    value = value.replace("\u0000", "\\0")
            .replace("'", "\\'")
            .replace("\\", "\\\\")
            .replace("\"", "\\\"")
            .replace("\n", "\\n")
            .replace("\r", "\\r")
            .replace("\t", "\\t");
    return "\""+ value+"\"";
}

Javafx webEngine executescript() cant send multiline string

Question

1 answers

solution1
0 2018-05-06 12:24:34

message received

Javafx webEngine executescript() cant send multiline string

Question

1 answers

solution1 0 2018-05-06 12:24:34

message received

solution1
0 2018-05-06 12:24:34