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");
