[英]Call a HTML program with javascript in a Java program
I am trying to run a HTML file with javascript from a java program . 我正在尝试从Java程序使用javascript运行HTML文件。
Map.html
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no">
<meta charset="utf-8">
<title>Circles</title>
<style>
html, body, #map-canvas {
height: 100%;
margin: 0px;
padding: 0px
}
</style>
<script type="text/javascript" src="https://maps.googleapis.com/maps/api/js?v=3.exp"></script>
<script>
// This example creates circles on the map, representing
// populations in North America.
// First, create an object containing LatLng and population for each city.
var citymap = [
['Chicago', 41.878113, -87.629798, 4],
['New York', 40.714352, -74.005973, 5],
['Los Angeles', 34.052234, -118.243684, 3],
['Vancouver',49.25, -123.1, 2],
['Oregon', 45, -120, 1]
];
var cityCircle;
function initialize() {
// Create the map.
var mapOptions = {
zoom: 4,
center: new google.maps.LatLng(37.09024, -95.712891),
mapTypeId: google.maps.MapTypeId.TERRAIN
};
var map = new google.maps.Map(document.getElementById('map-canvas'),
mapOptions);
// Construct the circle for each value in citymap.
// Note: We scale the area of the circle based on the population.
var fillcolor=[];
fillcolor[0]='#FF0000';fillcolor[1]='#FFFF00'; fillcolor[2]='#FF00FF'; fillcolor[3]='#00FF00';
var loop=0;
for (i = 0; i < citymap.length; i++) {
var populationOptions = {
strokeColor: '#000000',
strokeOpacity: 0.8,
strokeWeight: 2,
fillColor: fillcolor[loop],
fillOpacity: 0.35,
map: map,
center: new google.maps.LatLng(citymap[i][1], citymap[i][2]),
radius: Math.sqrt(citymap[i][3]) * 100000
};
// Add the circle for this city to the map.
cityCircle = new google.maps.Circle(populationOptions);
// cityCircle = new google.maps.Circle(populationOptions1);
loop=loop+1;
}
}
google.maps.event.addDomListener(window, 'load', initialize);
</script>
</head>
<body>
<div id="map-canvas"></div>
</body>
</html>
This program I am trying to call in the following program using ScriptEngine:- 我正在尝试使用ScriptEngine在以下程序中调用此程序:
public class RunJs {
public static void main(String[] args) throws IOException, JSONException, ScriptException {
// TODO Auto-generated method stub
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = manager.getEngineByName("html");
FileReader file = new FileReader("map.html");
engine.eval(file);
}
}
But this program doenst do anything and throws the below error 但是此程序确实做任何事情并抛出以下错误
Exception in thread "main" java.lang.NullPointerException
at google.api.search.RunJs.main(RunJs.java:28)
Is there any better way to call that html program from Java and display that html on a browser ? 有没有更好的方法从Java调用该html程序并在浏览器中显示该html? Can anyone please help me 谁能帮帮我吗
ScriptEngine::eval executes only javascript script. ScriptEngine :: eval仅执行javascript脚本。 It doesn't process HTML. 它不处理HTML。
Html page your can open in browser with Desktop::browse : 您可以使用Desktop :: browse在浏览器中打开的HTML页面:
Desktop.getDesktop().browse(new File("map.html").toURI());
PS You get NullPointerException
, because variable engine
is null
in your code. PS您会收到NullPointerException
,因为变量engine
在您的代码中为null
。
To get not null engine
, use, for example nashorn
name 要获取非null engine
,请使用例如nashorn
名称
manager.getEngineByName("nashorn");
"html"
is invalid param for ::getEngineByName by default (of course you can register your custom engine with method ::registerEngineName but you don't need it) 默认情况下, "html"
是:: getEngineByName的无效参数(当然,您可以使用:: registerEngineName方法注册自定义引擎,但不需要它)
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