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 UnaryMinusTest extends GroovyTestCase {
				
				    void testUnaryMinus() {
				        def value = -1
				        
				        assert value == -1
				        
				        def x = value + 2
				        assert x == 1
				        
				        def y = -value
				        assert y == 1
				    }   
				    
				    void testBug() {
				        def a = 1
				        def b = -a
				        
				        assert b == -1
				    }
				    
				    void testShellBug() {
				        assertScript("""
				def a = 1
				def b = -a
				assert b == -1            
				""")
				    }
				}