Enjoy 3.2 release ^_^

src/main/java/com/jfinal/kit/ElKit.java

@@ -0,0 +1,74 @@
+/**
+ * Copyright (c) 2011-2017, James Zhan 詹波 (jfinal@126.com).
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.jfinal.kit;
+
+import java.io.Writer;
+import java.util.Map;
+import com.jfinal.template.Directive;
+import com.jfinal.template.Engine;
+import com.jfinal.template.Env;
+import com.jfinal.template.Template;
+import com.jfinal.template.stat.Scope;
+
+/**
+ * EL 表达式语言求值工具类
+ * 
+ * <pre>
+ * 1：不带参示例
+ * 	  Integer value = ElKit.eval("1 + 2 * 3");
+ * 
+ * 2：带参示例
+ * 	  Kv data = Kv.by("a", 2).set("b", 3);
+ * 	  Integer value = ElKit.eval("1 + a * b", data);
+ * </pre>
+ */
+public class ElKit {
+	
+	private static Engine engine = new Engine();
+	private static final String RETURN_VALUE_KEY = "_RETURN_VALUE_";
+	
+	static {
+		engine.addDirective("eval", new InnerEvalDirective());
+	}
+	
+	public Engine getEngine() {
+		return engine;
+	}
+	
+	public static <T> T eval(String expr) {
+		return eval(expr, Kv.create());
+	}
+	
+	@SuppressWarnings("unchecked")
+	public static <T> T eval(String expr, Map<?, ?> data) {
+		String stringTemplate = "#eval(" + expr + ")";
+		Template template = engine.getTemplateByString(stringTemplate);
+		template.render(data, null);
+		return (T)data.get(RETURN_VALUE_KEY);
+	}
+	
+	public static class InnerEvalDirective extends Directive {
+		public void exec(Env env, Scope scope, Writer writer) {
+			Object value = exprList.eval(scope);
+			scope.set(RETURN_VALUE_KEY, value);
+		}
+	}
+}
+
+
+
+