Java中常用的设计模式之策略模式详解

package com.asurplus.common.strategy;
import lombok.AllArgsConstructor;
import lombok.Getter;

@Getter
@AllArgsConstructor
public enum OrderTypeEnum {
    COMMON(1001, "普通订单"),
    SECKILL(1002, "秒杀订单"),
    SPELL(1003, "拼团订单");
    int type;
    String desc;
}

package com.asurplus.common.strategy;

public interface OrderService {
    
    void createOrder();
    
    OrderTypeEnum type();
}

package com.asurplus.common.strategy;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

@Slf4j
@Service
public class CommonOrderServiceImpl implements OrderService {
    @Override
    public void createOrder() {
        log.info("创建 普通订单");
    }
    @Override
    public OrderTypeEnum type() {
        return OrderTypeEnum.COMMON;
    }
}

package com.asurplus.common.strategy;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

@Slf4j
@Service
public class SeckillOrderServiceImpl implements OrderService {
    @Override
    public void createOrder() {
        log.info("创建 秒杀订单");
    }
    @Override
    public OrderTypeEnum type() {
        return OrderTypeEnum.SECKILL;
    }
}

package com.asurplus.common.strategy;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

@Slf4j
@Service
public class SpellOrderServiceImpl implements OrderService {
    @Override
    public void createOrder() {
        log.info("创建 拼团订单");
    }
    @Override
    public OrderTypeEnum type() {
        return OrderTypeEnum.SPELL;
    }
}

package com.asurplus.common.strategy;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.util.List;
import java.util.Optional;

@Component
public class OrderManager {
    
    @Autowired
    private List<OrderService> orderServices;
    
    public void createOrder(int type) {
        
        Optional<OrderService> any = orderServices.stream().filter(f -> f.type().getType() == type).findAny();
        
        if (!any.isPresent()) {
            throw new RuntimeException("没有找到相应的订单实现");
        }
        // 创建订单
        any.get().createOrder();
    }
}

<!-- 测试依赖 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
</dependency>

package com.asurplus.common.strategy;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest
public class TestMain {
    @Autowired
    private OrderManager orderManager;
    @Test
    public void test() {
        // 创建 秒杀订单
        orderManager.createOrder(OrderTypeEnum.SECKILL.getType());
    }
}