java实现策略模式

创建策略接口

public interface Calculate {public int operation(int a, int b);}

实现接口

加法策略

@Component
public class AddCalculate implements Calculate {@Overridepublic int operation(int a, int b) {return a + a;}
}

减法策略

@Component
public class SubCalculate implements Calculate {@Overridepublic int operation(int a, int b) {return a - a;}
}

策略实现类

在springboot中，对于添加了 @Autowired 的map会自动将实现类注入到map中，key是beanid，value是注入的对象实例

@Component
public class CalculateFactory {@Autowiredprivate Map<String, Calculate> calculateMap;public int calculate(String calculate, int a, int b) throws Exception {return Optional.ofNullable(calculateMap.get(calculate)).orElseThrow(() -> new RuntimeException("异常")).operation(a, b);}}

使用

@RestController
@RequestMapping("/demo")
public class DemoController {@Autowiredprivate CalculateFactory calculateFactory;@GetMapping("/calculate")public int calculate() throws Exception {return calculateFactory.calculate("addCalculate", 1, 1);}}