java switch里面能用字符串的

之前一直觉得不可以，今天下了下居然可以，上网查了下，原来jdk7开始就可以了

public class OperationFactory {


public static Operation creatOperation(String op) {

Operation oper = null;

switch (op) {
case "+":
oper = new Add();
break;
case "-":
oper = new Sub();
break;
case "*":
oper = new Mul();
break;
case "/":
oper = new Div();
break;

default:
break;
}

return oper;

}

}