package com.asurplus.common.strategy;
import lombok.AllArgsConstructor;
import lombok.Getter;
/**
 * 訂單類型枚舉類
 */
@Getter
@AllArgsConstructor
public enum OrderTypeEnum {
    COMMON(1001, "普通訂單"),
    SECKILL(1002, "秒殺訂單"),
    SPELL(1003, "拼團訂單");
    int type;
    String desc;
}

package com.asurplus.common.strategy;
/**
 * 訂單處理接口
 */
public interface OrderService {
    /**
     * 創(chuàng)建訂單
     *
     * @return
     */
    void createOrder();
    /**
     * 獲取訂單類型
     *
     * @return
     */
    OrderTypeEnum type();
}

package com.asurplus.common.strategy;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
/**
 * 普通訂單處理器
 */
@Slf4j
@Service
public class CommonOrderServiceImpl implements OrderService {
    @Override
    public void createOrder() {
        log.info("創(chuàng)建 普通訂單");
    }
    @Override
    public OrderTypeEnum type() {
        return OrderTypeEnum.COMMON;
    }
}

package com.asurplus.common.strategy;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
/**
 * 秒殺訂單處理器
 */
@Slf4j
@Service
public class SeckillOrderServiceImpl implements OrderService {
    @Override
    public void createOrder() {
        log.info("創(chuàng)建 秒殺訂單");
    }
    @Override
    public OrderTypeEnum type() {
        return OrderTypeEnum.SECKILL;
    }
}

package com.asurplus.common.strategy;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
/**
 * 拼團訂單處理器
 */
@Slf4j
@Service
public class SpellOrderServiceImpl implements OrderService {
    @Override
    public void createOrder() {
        log.info("創(chuàng)建 拼團訂單");
    }
    @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;
/**
 * 訂單管理器
 */
@Component
public class OrderManager {
    /**
     * Autowired 注解的強大之處
     */
    @Autowired
    private List<OrderService> orderServices;
    /**
     * 創(chuàng)建訂單
     *
     * @param type 訂單類型
     * @return
     */
    public void createOrder(int type) {
        /**
         * 根據(jù)訂單類型，找到對應的處理器
         */
        Optional<OrderService> any = orderServices.stream().filter(f -> f.type().getType() == type).findAny();
        /**
         * 沒有對應的處理器
         */
        if (!any.isPresent()) {
            throw new RuntimeException("沒有找到相應的訂單實現(xiàn)");
        }
        // 創(chuàng)建訂單
        any.get().createOrder();
    }
}

<!-- 測試依賴 -->
<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;
/**
 * 策略模式
 */
@RunWith(SpringRunner.class)
@SpringBootTest
public class TestMain {
    @Autowired
    private OrderManager orderManager;
    @Test
    public void test() {
        // 創(chuàng)建 秒殺訂單
        orderManager.createOrder(OrderTypeEnum.SECKILL.getType());
    }
}