[英]Why does not Rhino (jsr-223) evaluate a string when it is an attribute of an object?
為什么當對象的屬性是jsr-223時不評估字符串?
僅具有一個String屬性的簡單類:
public class EvalJSR223Bean {
public String evalFnt;
}
使用文本和對象進行簡單評估,使用該對象時,Rhino不執行評估。 但是,如果我將空的javascript字符串連接到對象屬性,則Rhino eval。
public static void main(String[] args) throws ScriptException {
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = manager.getEngineByName("JavaScript");
engine.eval("function f2() {println('EXECUTED!!!!!')}; function f1(source) { return eval(source); };");
String evalFnt = "(function(){f2();return '0';})();";
engine.put("evalFnt", evalFnt);
engine.eval("f1(evalFnt);"); // f2 is executed.
EvalJSR223Bean bean = new EvalJSR223Bean();
bean.evalFnt = evalFnt;
engine.put("bean1", bean.evalFnt);
engine.eval("f1(bean1.evalFnt);"); // Why does NOT executed f2 ?!!.
engine.put("bean", bean);
engine.eval("f1(bean.evalFnt);"); // Why does NOT executed f2 ?!!.
engine.put("bean", bean);
engine.eval("f1( ''+bean.evalFnt );"); // And if I concatenate a string, f2 is executed!!!
}
如果字符串不是“ string”類型,則eval
忽略該字符串:
eval(new String('console.log("foo");'));
因此,這可能是Rhino如何將該屬性視為“對象”類型的結果。 put
字符串放入引擎時,它必須將其轉換為值類型。
這段代碼:
import javax.script.*;
public class ScriptDemo {
public static class Bar {
public String bar = "bar";
}
public static void main(String[] args) throws ScriptException {
ScriptEngine engine =
new ScriptEngineManager().getEngineByName("JavaScript");
engine.put("foo", "foo");
engine.put("bar", new Bar());
engine.eval("println(typeof foo);");
engine.eval("println(typeof bar.bar);");
engine.eval("println(typeof String(bar.bar));");
engine.eval("println(typeof new String(bar.bar));");
}
}
輸出:
string
object
string
object
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