步骤一:定义接口
public interface ICalculator { public int calculate(String exp); }
步骤二:定义个抽象类(可有可无,用于辅助)
public abstract class AbstractCalculator { public int[] split(String exp,String opt){ String array[] = exp.split(opt); int arrayInt[] = new int[2]; arrayInt[0] = Integer.parseInt(array[0]); arrayInt[1] = Integer.parseInt(array[1]); return arrayInt; } }
步骤三:定义实现类,继承抽象类,实现接口
public class Minus extends AbstractCalculator implements ICalculator{ @Override public int calculate(String exp) { int[] arrayInt=split(exp,"-"); return arrayInt[0]-arrayInt[1]; } }
步骤四:测试
public class StrategyTest { public static void main(String[] args) { String exp="2+8"; ICalculator cal=new Plus(); int result=cal.calculate(exp); System.out.println("2+8="+result); } }