场景

1. 场景介绍

公司在做一个物联卡相关的项目时，需要对多个卡供应商（移动、联通、电信的下级卡片代理商，公司已经接入了5家卡片供应商）的接口进行调用，我负责将不同供应商的接口进行整合，形成一个统一的调用接口，大概的流程如下。

image

比较常见的实现方式是通过if - else if - else来进行不同供应商的选择，但是使用if-else 时，随着供应商的不断增多，else if的代码会越来越多,越来越复杂，不利于扩展，违反了开闭原则（对扩展开放，对修改关闭）

2. 其他类似场景

2.1 接入多家三方支付公司接口

2.2 接入多种加密方式

2.3 接入多种登录方式

2.4 接入多家物流公司接口

3. 如何干掉 if-else 语句？

使用工厂方法模式+模板方法模式，感觉我的代码实现和这两个设计模式比较接近，代码结构如下。

image

代码

1. 配置

1.1 添加配置类

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

import java.util.Map;

@Data
@Component
@ConfigurationProperties(prefix = "esim")
public class EsimSupplierProp {

    private Map<Long, SupplierInfo> suppliers;

    @Data
    public static class SupplierInfo {
        private String name;
        private String className;
    }

}

1.2 添加配置文件

配置供应商key(supplierId)、name(供应商名称)、class-name(全类名，通过反射创建实例)

esim:
  suppliers:
    1:
      name: 中国移动
      class-name: com.gnl.auth.test.service.SupplierYiDong
    2:
      name: 中国联通
      class-name: com.gnl.auth.test.service.SupplierLianTong
    3:
      name: 中国电信
      class-name: com.gnl.auth.test.service.SupplierDianXin

2. 添加实体类

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.math.BigDecimal;

@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class Esim {
    private Long esimId;
    private Long esimSupplierId;
    private String msisdn;
    private BigDecimal packagePrice;
    private BigDecimal packageCapacity;
}

3. 添加供应商模板方法抽象类

import com.gnl.auth.test.config.EsimSupplierProp;
import com.gnl.auth.test.entity.Esim;
import lombok.Data;

@Data
public abstract class EsimSupplier {

    /**
     * 供应商信息
     */
    private EsimSupplierProp.SupplierInfo supplierInfo;

    /**
     * 卡信息
     */
    public abstract Esim info(Esim esim);

    /**
     * 停机
     */
    public abstract Boolean stop(Esim esim);

    /**
     * 复机
     */
    public abstract Boolean reply(Esim esim);

    /**
     * 卡充值
     */
    public Boolean recharge(Esim esim) {
        throw new RuntimeException(supplierInfo.getName() + "不支持充值操作");
    }

}

4. 添加供应商工厂类并注入

添加工厂类

方法一：通过配置文件和反射拿到所有供应商实现类

import com.gnl.auth.test.config.EsimSupplierProp;
import com.gnl.auth.test.service.EsimSupplier;

import java.util.HashMap;
import java.util.Map;

public class EsimSupplierFactory {
    /**
     * 供应商服务map
     */
    private Map<Long, EsimSupplier> esimSupplierMap;

    /**
     * 构造函数
     *
     * @param esimSupplierProp 配置文件
     */
    public EsimSupplierFactory(EsimSupplierProp esimSupplierProp) {
        // 初始化map
        this.esimSupplierMap = new HashMap<>();
        // 遍历配置文件
        Map<Long, EsimSupplierProp.SupplierInfo> suppliers = esimSupplierProp.getSuppliers();
        for (Map.Entry<Long, EsimSupplierProp.SupplierInfo> supplier : suppliers.entrySet()) {
            try {
                // 使用反射创建供应商服务对象，并设置进map中
                Class<?> classBook = Class.forName(supplier.getValue().getClassName());
                EsimSupplier esimSupplier = (EsimSupplier) classBook.newInstance();
                // 设置供应商信息
                esimSupplier.setSupplierInfo(supplier.getValue());
                esimSupplierMap.put(supplier.getKey(), esimSupplier);
            } catch (ClassNotFoundException e) {
                throw new RuntimeException(supplier.getValue().getName() + "供应商不存在", e);
            } catch (IllegalAccessException e) {
                throw new RuntimeException(supplier.getValue().getName() + "供应商不存在", e);
            } catch (InstantiationException e) {
                throw new RuntimeException(supplier.getValue().getName() + "供应商不存在", e);
            }
        }
    }

    /**
     * 获取供应商服务
     */
    public EsimSupplier getEsimSupplier(Long supplierId) {
        EsimSupplier esimSupplier = esimSupplierMap.get(supplierId);
        if (esimSupplier == null) {
            throw new RuntimeException("卡供应商不存在");
        }
        return esimSupplier;
    }

}

注入工厂类

import com.gnl.auth.test.factory.EsimSupplierFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class EsimSupplierConfig {
    /**
     * 注入工厂
     */
    @Bean
    public EsimSupplierFactory EsimSupplierFactory(EsimSupplierProp esimSupplierProp) {
        return new EsimSupplierFactory(esimSupplierProp);
    }
}

5. 添加不同供应商实现类

5.1 中国移动

import com.alibaba.fastjson.JSON;
import com.gnl.auth.test.config.EsimSupplierProp;
import com.gnl.auth.test.entity.Esim;
import lombok.extern.log4j.Log4j2;

import java.math.BigDecimal;

@Log4j2
public class SupplierYiDong extends EsimSupplier {
    @Override
    public Esim info(Esim esim) {
        Esim info = Esim.builder()
                .esimId(esim.getEsimId())
                .esimSupplierId(1L)
                .msisdn("1800000000" + esim.getEsimId())
                .packageCapacity(new BigDecimal(2048))
                .packagePrice(new BigDecimal(22))
                .build();
        log.info("移动卡查询成功: {}", JSON.toJSONString(info));
        EsimSupplierProp.SupplierInfo supplierInfo = this.getSupplierInfo();
        log.info("移动配置: {}",JSON.toJSONString(supplierInfo));
        return info;
    }

    @Override
    public Boolean stop(Esim esim) {
        log.info("移动卡停机成功: {}", esim.getEsimId());
        return true;
    }

    @Override
    public Boolean reply(Esim esim) {
        log.info("移动卡复机成功: {}", esim.getEsimId());
        return true;
    }
}

5.1 中国联通

import com.alibaba.fastjson.JSON;
import com.gnl.auth.test.config.EsimSupplierProp;
import com.gnl.auth.test.entity.Esim;
import lombok.extern.log4j.Log4j2;

import java.math.BigDecimal;

@Log4j2
public class SupplierLianTong extends EsimSupplier {
    @Override
    public Esim info(Esim esim) {
        Esim info = Esim.builder()
                .esimId(esim.getEsimId())
                .esimSupplierId(2L)
                .msisdn("1800000000" + esim.getEsimId())
                .packageCapacity(new BigDecimal(3072))
                .packagePrice(new BigDecimal(33))
                .build();
        log.info("联通卡查询成功: {}", JSON.toJSONString(info));
        EsimSupplierProp.SupplierInfo supplierInfo = this.getSupplierInfo();
        log.info("联通配置: {}", JSON.toJSONString(supplierInfo));
        return info;
    }

    @Override
    public Boolean stop(Esim esim) {
        log.info("联通卡停机成功: {}", esim.getEsimId());
        return true;
    }

    @Override
    public Boolean reply(Esim esim) {
        log.info("联通卡复机成功: {}", esim.getEsimId());
        return true;
    }
}

5.1 中国电信

import com.alibaba.fastjson.JSON;
import com.gnl.auth.test.config.EsimSupplierProp;
import com.gnl.auth.test.entity.Esim;
import lombok.extern.log4j.Log4j2;

import java.math.BigDecimal;

@Log4j2
public class SupplierDianXin extends EsimSupplier {

    @Override
    public Esim info(Esim esim) {
        Esim info = Esim.builder()
                .esimId(esim.getEsimId())
                .esimSupplierId(3L)
                .msisdn("1800000000" + esim.getEsimId())
                .packageCapacity(new BigDecimal(6144))
                .packagePrice(new BigDecimal(66))
                .build();
        log.info("电信卡查询成功: " + JSON.toJSONString(info));
        EsimSupplierProp.SupplierInfo supplierInfo = this.getSupplierInfo();
        log.info("电信配置: {}",JSON.toJSONString(supplierInfo));
        return info;
    }

    @Override
    public Boolean stop(Esim esim) {
        log.info("电信卡停机成功: {}", esim.getEsimId());
        return true;
    }

    @Override
    public Boolean reply(Esim esim) {
        log.info("电信卡复机成功: {}", esim.getEsimId());
        return true;
    }

    public Boolean recharge(Esim esim){
        log.info("电信卡充值成功: {}", esim.getEsimId());
        return true;
    }
}

6. 测试

6.1 添加测试类

import com.gnl.auth.test.entity.Esim;
import com.gnl.auth.test.factory.EsimSupplierFactory;
import com.gnl.auth.test.service.EsimSupplier;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
public class EsimTest {

    @Autowired
    private EsimSupplierFactory esimSupplierFactory;

    @Test
    void test1() {
        // 移动
        Esim esim = Esim.builder().esimId(1L).esimSupplierId(1l).build();
        // 联通
//        Esim esim = Esim.builder().esimId(2L).esimSupplierId(2l).build();
        // 电信
//        Esim esim = Esim.builder().esimId(3L).esimSupplierId(3l).build();

        EsimSupplier esimSupplier = esimSupplierFactory.getEsimSupplier(esim.getEsimSupplierId());

        esimSupplier.info(esim);
        esimSupplier.stop(esim);
        esimSupplier.reply(esim);
        esimSupplier.recharge(esim);
    }

}

6.2 测试结果

中国移动

image

中国联通

image

中国电信

image

7. 拓展新供应商

拓展新的供应商只需要两个步骤，第一个步骤：添加配置，第二个步骤：实现供应商接口，具体如下。

7.1 添加配置文件

image

7.2 实现供应商接口

继承EsimSupplier，重写抽象类里的方法即可。

image

8. EsimSupplier的实现类中使用SpringBean方法

https://www.jianshu.com/p/8b3864623a42

9.之后学到的更优雅的办法

9.1 供应商实现类都加上@Component，注册为SpringBean

9.2 创建获取SpringBean的工具类

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

import java.util.Map;

@Component
public class SpringUtil implements ApplicationContextAware {

    private static ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        if (SpringUtil.applicationContext == null) {
            SpringUtil.applicationContext = applicationContext;
        }
    }

    //获取applicationContext
    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    //通过name获取 Bean.
    public static Object getBean(String name) {
        return applicationContext.getBean(name);
    }

    //通过class获取Bean.
    public static <T> T getBean(Class<T> clazz) {
        return applicationContext.getBean(clazz);
    }

    //通过name,以及Clazz返回指定的Bean
    public static <T> T getBean(String name, Class<T> clazz) {
        return applicationContext.getBean(name, clazz);
    }

    //通过Class返回指定的BeanMap
    public static <T> Map<String, T> getBeansOfType(Class<T> clazz) {
        return applicationContext.getBeansOfType(clazz);
    }
}

9.3 创建工厂类

import vip.gnloypp.test.svc.config.SpringUtil;
import vip.gnloypp.test.svc.service.EsimSupplier;

import java.util.Map;

public class EsimSupplierFactory {

    // 获取所有 EsimSupplier 的实现类
    private static Map<String, EsimSupplier> beansMap;
    static {
        // 通过SpringBean工具类获取所有 EsimSupplier 的实现类
        beansMap = SpringUtil.getBeansOfType(EsimSupplier.class);
    }

    // 根据实现类beanName获取实现类
    public static EsimSupplier getEsimSupplier(String esimSupplierName) {
        EsimSupplier esimSupplier = beansMap.get(esimSupplierName);
        if(esimSupplier == null){
            throw new RuntimeException("供应商不存在");
        }
        return esimSupplier;
    }
}

9.4 查询esim卡信息获取相应的供应商beanName，得到供应商实现类

EsimSupplier supplierYiDong= EsimSupplierFactory.getEsimSupplier("supplierYiDong");
EsimSupplier supplierDianXin= EsimSupplierFactory.getEsimSupplier("supplierDianXin");
EsimSupplier supplierLianTong= EsimSupplierFactory.getEsimSupplier("supplierLianTong");