如何在java8的JavaScript引擎中使用java对象

Question

我想在 javascript 引擎中使用 java 对象，但无法执行并获得异常：javax.script.ScriptException: :1:11 Expected ;但找到了

ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
Object map = engine.eval("var HashMap<String,String> = Java.type('java.util.HashMap<String,String>()');" +
                      "var map = new HashMap();" +
                      "map.put('key1', 'value1');" +
                      "map.put('key2', 'value2');" +
                      "map.put('key3', 'value3');" +
                      "map");
            System.out.println(map);

Answer 1

用这段代码试试，正常工作。

ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
Object map = engine.eval("var HashMap = Java.type('java.util.HashMap');" +
            "var map = new HashMap();" +
            "map.put('key1', 'value1');" +
            "map.put('key2', 'value2');" +
            "map.put('key3', 'value3');" +
            "map");
System.out.println(map);

问题出在脚本的第一行：

var HashMap<String,String> = Java.type('java.util.HashMap<String,String>()');

而不是

var HashMap = Java.type('java.util.HashMap');

---

但您也可以将地图注入到您的脚本中，并像这样在脚本上对其进行操作：

Map<String, String> map = new HashMap<>();
ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
engine.getContext().getBindings(ScriptContext.GLOBAL_SCOPE).put ("map", map);
engine.eval("map.put('key1', 'value1');" +
            "map.put('key2', 'value2');" +
            "map.put('key3', 'value3');");
System.out.println(map);