用jakarta commons JEXL在JAVA中运算表达式

java 代码

 1. import org.apache.commons.jexl.Expression;
 2. import org.apache.commons.jexl.ExpressionFactory;
 3. import org.apache.commons.jexl.JexlContext;
 4. import org.apache.commons.jexl.JexlHelper;
 5.
 6. import junit.framework.TestCase;
 7.
 8. public class JexlTest extends TestCase {
 9.     public void test() throws Exception {
10.
11.         //Create an expression object
12.         String jexlExp = "9*(1+2)";
13.         Expression e = ExpressionFactory.createExpression(jexlExp);
14.
15.         // Create a context
16.         JexlContext jc = JexlHelper.createContext();
17.
18.         // Now evaluate the expression, getting the result
19.         Object result = e.evaluate(jc);
20.
21.         System.out.println("result:" + result);
22.         System.out.println("result type:" + result.getClass().getName());
23.
24.         assertEquals(((Long) result).intValue(), 27);
25.     }
26. }