add engine and fix bug

hutool-extra/pom.xml

@@ -413,7 +413,7 @@
 		<dependency>
 			<groupId>org.mozilla</groupId>
 			<artifactId>rhino</artifactId>
-			<version>1.7.12</version>
+			<version>1.7.13</version>
 			<scope>compile</scope>
 			<optional>true</optional>
 		</dependency>

hutool-extra/src/main/java/cn/hutool/extra/expression/engine/rhino/RhinoEngine.java

@@ -1,5 +1,6 @@
 package cn.hutool.extra.expression.engine.rhino;
 
+import cn.hutool.core.map.MapUtil;
 import cn.hutool.extra.expression.ExpressionEngine;
 import org.mozilla.javascript.Context;
 import org.mozilla.javascript.Scriptable;
@@ -11,30 +12,22 @@ import java.util.Map;
  * rhino引擎封装<br>
  * 见：https://github.com/mozilla/rhino
  *
- * @since 5.5.2
  * @author lzpeng
+ * @since 5.5.2
  */
 public class RhinoEngine implements ExpressionEngine {
 
-	/**
-	 * 构造
-	 */
-	public RhinoEngine(){
-	}
-
 	@Override
 	public Object eval(String expression, Map<String, Object> context) {
-		Context ctx = Context.enter();
-		Scriptable scope = ctx.initStandardObjects();
-		if (context != null && !context.isEmpty()) {
-			for (Map.Entry<String, Object> entry : context.entrySet()) {
-				// 将java对象转为js对象
-				Object jsObj = Context.javaToJS(entry.getValue(), scope);
-				// 将java对象放置JS的作用域中
-				ScriptableObject.putProperty(scope, entry.getKey(), jsObj);
-			}
+		final Context ctx = Context.enter();
+		final Scriptable scope = ctx.initStandardObjects();
+		if (MapUtil.isNotEmpty(context)) {
+			context.forEach((key, value)->{
+				// 将java对象转为js对象后放置于JS的作用域中
+				ScriptableObject.putProperty(scope, key, Context.javaToJS(value, scope));
+			});
 		}
-		Object result = ctx.evaluateString(scope, expression, "rhino.js", 1, null);
+		final Object result = ctx.evaluateString(scope, expression, "rhino.js", 1, null);
 		Context.exit();
 		return result;
 	}