Groovy动态语言 运行在JVM中的动态语言 可以方便的处理业务逻辑变化大的业务

				class NegationTests extends GroovyTestCase {
				
				    void testNegateInteger() {
				        def a = -1
				        assert a == -1
				    }
				
				    void testNegateIntegerExpression() {
				        def a = -1
				        a = -a
				        assert a == 1
				    }
				
				    void testNegateDouble() {
				        def a = -1.0
				        assert a == -1.0
				    }
				
				    void testNegateDoubleExpression() {
				        def a = -1.0
				        a = -a
				        assert a == 1.0
				    }
				
				}