【设计模式】【第四章】【订单状态流转】【状态模式 + 享元模式+模板方法模式】

文章目录

创建design-demo项目
- 创建OrderController
- 创建OrderService
- 创建OrderServiceImpl
- 创建AbstractAuditLogProcessor
- 创建AuditLog
- 创建LoginLogProcessor
- 创建OrderLogProcessor
- 创建PayLogProcessor
- 创建Order
- 创建OrderState
- 创建OrderStateChangeAction
- 创建OrderStateMachineConfig
- 创建OrderStateListener
- 创建StrategyFacade
- 创建AddFuncFactory
- 创建PayFactory
- 创建StrategyFactory
- 创建AddFuncDecorator
- 创建AbstractAddFuncDecorator
- 创建StrategyEnum
- 校验是否正常工作

创建design-demo项目

项目代码：https://gitee.com/java_wxid/java_wxid/tree/master/demo/design-demo
项目结构如下（示例）：

创建OrderController

代码如下（示例）：

package com.example.designdemo.controller;import com.example.designdemo.order.pojo.Order;
import com.example.designdemo.pay.pojo.PayBody;
import com.example.designdemo.service.OrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
/*** @Author: zhiwei Liao* @Date: 2022/9/26 21:29* @Description: 订单管理，这里简单写写，主要是设计模式，别抠细节*/
@RestController
public class OrderController {@Autowiredprivate OrderService orderService;@GetMapping("mkOrder")public Order createOrder(@RequestParam Integer oid) {return orderService.createOrder(oid);}@PostMapping("/pay")public Order payOrder(@RequestBody PayBody payBody){return orderService.pay(payBody);}@GetMapping("/send")public Order send(@RequestParam Integer oid) {return orderService.send(oid);}@GetMapping("/receive")public Order receive(@RequestParam Integer oid) {return orderService.receive(oid);}
}

创建OrderService

代码如下（示例）：

package com.example.designdemo.service;import com.example.designdemo.order.pojo.Order;
import com.example.designdemo.pay.pojo.PayBody;/*** @Author: zhiwei Liao* @Date: 2022/9/25 9:28* @Description:*/
public interface OrderService {Order createOrder(Integer oid);Order pay(PayBody payBody);Order send(Integer oid);Order receive(Integer oid);
}

创建OrderServiceImpl

代码如下（示例）：
package com.example.designdemo.service.impl;

import com.example.designdemo.order.auditlog.OrderLogProcessor;
import com.example.designdemo.order.auditlog.PayLogProcessor;
import com.example.designdemo.order.pojo.Order;
import com.example.designdemo.order.pojo.OrderState;
import com.example.designdemo.order.pojo.OrderStateChangeAction;
import com.example.designdemo.pay.facade.StrategyFacade;
import com.example.designdemo.pay.pojo.PayBody;
import com.example.designdemo.service.OrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.statemachine.StateMachine;
import org.springframework.statemachine.persist.StateMachinePersister;
import org.springframework.stereotype.Service;
import java.util.ArrayList;
import java.util.List;
/**

@Author: zhiwei Liao
@Date: 2022/9/26 21:29
@Description:
*/
@Service
public class OrderServiceImpl implements OrderService {

@Autowired
private StateMachine<OrderState, OrderStateChangeAction> orderStateMachine;

@Autowired
private StateMachinePersister<OrderState, OrderStateChangeAction, Order> stateMachinePersister;

@Autowired
private PayLogProcessor payLogProcessor;

@Autowired
private OrderLogProcessor orderLogProcessor;

//模拟一个存储
private List orders = new ArrayList<>();

public Order createOrder(Integer oid) {
Order order = new Order();
order.setOrderState(OrderState.ORDER_WAIT_PAY);
order.setOrderId(oid);
// 创建的order是不是得入库啊？如果不入库，下次访问的时候，是不是找不到了啊。
orders.add(order); // 模拟存储到 db
orderLogProcessor.processAuditLog(“acccount”, “createOrder”, oid.toString());
return order;
}

// 将来我们删除或者增加或者修改任何关于付款的模块，无需改动service。
//不会对调用层产生任何代码的改动。
// 调用层使用我们的pay 模块，无需关系实现的逻辑，只需要将入参传给我们的pay模块即可。
public Order pay(PayBody payBody) {
// 书写我们的付款逻辑
boolean flag = false;
flag = StrategyFacade.pay(payBody);
if(flag) {
Order order = (Order) orders.get(0); // 模拟查询db代码
payLogProcessor.processAuditLog(payBody.getAccount(), “pay”, order.getOrderId().toString());
Message message = MessageBuilder
.withPayload(OrderStateChangeAction.PAY_ORDER).setHeader(“order”, order).build();
//发送消息，发送给谁？和状态机有没有关系啊？有
if(changeStateAction(message,order)) {
return order;
}
//如果是 true，我们要保存到db
saveToDb(payBody);
}
return null;
}
private void saveToDb(PayBody payBody) {
}

public Order send(Integer oid) {
Order order = (Order) orders.get(0); // 模拟查询db代码
Message message = MessageBuilder
.withPayload(OrderStateChangeAction.SEND_ORDER).setHeader(“order”, order).build();
if(changeStateAction(message,order)) {
return order;
}
return null;
}

public Order receive(Integer oid) {
Order order = (Order) orders.get(0); // 模拟查询db代码
Message message = MessageBuilder
.withPayload(OrderStateChangeAction.RECEIVE_ORDER).setHeader(“order”, order).build();
if(changeStateAction(message,order)) {
return order;
}
return null;
}

private boolean changeStateAction(Message message, Order order) {
try {
orderStateMachine.start();
stateMachinePersister.restore(orderStateMachine, order); // 待议
boolean res = orderStateMachine.sendEvent(message);
stateMachinePersister.persist(orderStateMachine, order); // 持久
return res;
} catch (Exception e) {
e.printStackTrace();
} finally {
orderStateMachine.stop();
}
return false;
}
}

创建AbstractAuditLogProcessor

代码如下（示例）：

package com.example.designdemo.order.auditlog;import com.example.designdemo.order.auditlog.pojo.AuditLog;import java.util.Date;
/*** @Author: zhiwei Liao* @Date: 2022/9/26 21:29* @Description:*/
public abstract class AbstractAuditLogProcessor {// 创建我们的 AuditLog (基础部分）public final AuditLog buildAuditLog(String account, String action, String orderId){AuditLog auditLog = new AuditLog();auditLog.setAccount(account);auditLog.setAction(action);auditLog.setOrderId(orderId);auditLog.setDate(new Date());return auditLog;}protected abstract AuditLog buildDetails(AuditLog auditLog);public final void sendToQueue(AuditLog auditLog) {//send toQueue(auditLog)}public final void processAuditLog(String account, String action, String orderId) {this.sendToQueue(buildDetails(buildAuditLog(account, action, orderId)));}
}

创建AuditLog

代码如下（示例）：
package com.example.designdemo.order.auditlog.pojo;

import java.util.Date;
/**

@Author: zhiwei Liao
@Date: 2022/9/26 21:29
@Description:
*/
public class AuditLog {
private String account;
private String action;
private Date date;
private String orderId;
private Object details; //订单创建需要有相关产品信息；
// 订单支付需要有相关产品信息以及支付方式和支付金额。

public String getAccount() {
return account;
}

public void setAccount(String account) {
this.account = account;
}

public String getAction() {
return action;
}

public void setAction(String action) {
this.action = action;
}

public Date getDate() {
return date;
}

public void setDate(Date date) {
this.date = date;
}

public String getOrderId() {
return orderId;
}

public void setOrderId(String orderId) {
this.orderId = orderId;
}

public Object getDetails() {
return details;
}

public void setDetails(Object details) {
this.details = details;
}

@Override
public String toString() {
return “AuditLog{” +
“account='” + account + ‘’’ +
“, action='” + action + ‘’’ +
“, date=” + date +
“, orderId='” + orderId + ‘’’ +
“, details=” + details +
‘}’;
}
}

创建LoginLogProcessor

代码如下（示例）：

package com.example.designdemo.order.auditlog;import com.example.designdemo.order.auditlog.pojo.AuditLog;
import org.springframework.stereotype.Component;
/*** @Author: zhiwei Liao* @Date: 2022/9/26 21:29* @Description:*/
@Component
public class LoginLogProcessor extends AbstractAuditLogProcessor{@Overrideprotected AuditLog buildDetails(AuditLog auditLog) {return auditLog;}
}

创建OrderLogProcessor

代码如下（示例）：

package com.example.designdemo.order.auditlog;import com.example.designdemo.order.auditlog.pojo.AuditLog;
import org.springframework.stereotype.Component;
/*** @Author: zhiwei Liao* @Date: 2022/9/26 21:29* @Description:*/
@Component
public class OrderLogProcessor extends AbstractAuditLogProcessor{@Overrideprotected AuditLog buildDetails(AuditLog auditLog) {String orderId = auditLog.getOrderId();String productDetails = "通过 orderId 获取";auditLog.setDetails(productDetails);System.out.println(auditLog);return auditLog;}
}

创建PayLogProcessor

代码如下（示例）：

package com.example.designdemo.order.auditlog;import com.example.designdemo.order.auditlog.pojo.AuditLog;
import org.springframework.stereotype.Component;
/*** @Author: zhiwei Liao* @Date: 2022/9/26 21:29* @Description:*/
@Component
public class PayLogProcessor extends AbstractAuditLogProcessor{@Overrideprotected AuditLog buildDetails(AuditLog auditLog) {String orderId = auditLog.getOrderId();String allDetails = "通过 orderId 或者是参数 获取产品信息，金额，支付方式";auditLog.setDetails(allDetails);System.out.println(auditLog);return auditLog;}
}

创建Order

代码如下（示例）：

package com.example.designdemo.order.pojo;/*** @Author: zhiwei Liao* @Date: 2022/9/26 21:29* @Description:状态转化的一个控制机。状态机：初始化状态；配置我们的所有状态之间的转化关系；一些持久化的工作（redis）。*/
public class Order {private Integer orderId;private OrderState orderState;//订单状态public Integer getOrderId() {return orderId;}public void setOrderId(Integer orderId) {this.orderId = orderId;}public OrderState getOrderState() {return orderState;}public void setOrderState(OrderState orderState) {this.orderState = orderState;}
}

创建OrderState

代码如下（示例）：

package com.example.designdemo.order.pojo;
/*** @Author: zhiwei Liao* @Date: 2022/9/26 21:29* @Description:订单状态*/
public enum  OrderState {ORDER_WAIT_PAY, // 待支付ORDER_WAIT_SEND, // 待发货ORDER_WAIT_RECEIVE, // 待收货ORDER_FINISH; // 完成订单
}

创建OrderStateChangeAction

代码如下（示例）：

package com.example.designdemo.order.pojo;
/*** @Author: zhiwei Liao* @Date: 2022/9/26 21:29* @Description:订单状态操作*/
public enum OrderStateChangeAction {PAY_ORDER, // 支付操作SEND_ORDER, // 发货操作RECEIVE_ORDER; // 收货操作
}

创建OrderStateMachineConfig

代码如下（示例）：

package com.example.designdemo.order.config;import com.example.designdemo.order.pojo.Order;
import com.example.designdemo.order.pojo.OrderState;
import com.example.designdemo.order.pojo.OrderStateChangeAction;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.statemachine.StateMachineContext;
import org.springframework.statemachine.StateMachinePersist;
import org.springframework.statemachine.config.EnableStateMachine;
import org.springframework.statemachine.config.StateMachineConfigurerAdapter;
import org.springframework.statemachine.config.builders.StateMachineStateConfigurer;
import org.springframework.statemachine.config.builders.StateMachineTransitionConfigurer;
import org.springframework.statemachine.persist.DefaultStateMachinePersister;
import org.springframework.statemachine.support.DefaultStateMachineContext;
import java.util.EnumSet;
/*** @Author: zhiwei Liao* @Date: 2022/9/26 21:29* @Description:*/
@Configuration
@EnableStateMachine(name="orderStateMachine")
public class OrderStateMachineConfig extends StateMachineConfigurerAdapter<OrderState, OrderStateChangeAction> {public void configure(StateMachineStateConfigurer<OrderState, OrderStateChangeAction> states) throws Exception {states.withStates().initial(OrderState.ORDER_WAIT_PAY).states(EnumSet.allOf(OrderState.class));}public void configure(StateMachineTransitionConfigurer<OrderState, OrderStateChangeAction> transitions) throws Exception {transitions.withExternal().source(OrderState.ORDER_WAIT_PAY).target(OrderState.ORDER_WAIT_SEND).event(OrderStateChangeAction.PAY_ORDER).and().withExternal().source(OrderState.ORDER_WAIT_SEND).target(OrderState.ORDER_WAIT_RECEIVE).event(OrderStateChangeAction.SEND_ORDER).and().withExternal().source(OrderState.ORDER_WAIT_RECEIVE).target(OrderState.ORDER_FINISH).event(OrderStateChangeAction.RECEIVE_ORDER);}// 配置状态机持久化@Beanpublic DefaultStateMachinePersister machinePersister() {return new DefaultStateMachinePersister<>(new StateMachinePersist<Object, Object, Order>() {@Overridepublic void write(StateMachineContext<Object, Object> stateMachineContext, Order order) throws Exception {//持久化操作。可以通过任何形式进行持久化。redis 、 mongodb、mysql，ecache}@Overridepublic StateMachineContext<Object, Object> read(Order order) throws Exception {// 本来是应该从持久化组件里进行读取的。但是没做持久化return new DefaultStateMachineContext(order.getOrderState(), null, null, null);}});}
}

创建OrderStateListener

代码如下（示例）：

package com.example.designdemo.order.listener;import com.example.designdemo.order.pojo.Order;
import com.example.designdemo.order.pojo.OrderState;
import com.example.designdemo.order.pojo.OrderStateChangeAction;
import org.springframework.messaging.Message;
import org.springframework.statemachine.annotation.OnTransition;
import org.springframework.statemachine.annotation.WithStateMachine;
import org.springframework.stereotype.Component;/*** @Author: zhiwei Liao* @Date: 2022/9/26 21:29* @Description:监听器是监听到 action 后进行状态的一个变更。*/
@Component("orderStateListener")
@WithStateMachine(name="orderStateMachine")
public class OrderStateListener {@OnTransition(source = "ORDER_WAIT_PAY", target = "ORDER_WAIT_SEND")public boolean payToSend(Message<OrderStateChangeAction> message){Order order = (Order) message.getHeaders().get("order");order.setOrderState(OrderState.ORDER_WAIT_SEND);return true;}@OnTransition(source = "ORDER_WAIT_SEND", target = "ORDER_WAIT_RECEIVE")public boolean sendToReceive(Message<OrderStateChangeAction> message){Order order = (Order) message.getHeaders().get("order");order.setOrderState(OrderState.ORDER_WAIT_RECEIVE);return true;}@OnTransition(source = "ORDER_WAIT_RECEIVE", target = "ORDER_FINISH")public boolean receiveToFinish(Message<OrderStateChangeAction> message){Order order = (Order) message.getHeaders().get("order");order.setOrderState(OrderState.ORDER_FINISH);return true;}}

创建StrategyFacade

代码如下（示例）：

package com.example.designdemo.pay.facade;import com.example.designdemo.pay.additionalDecorator.AddFuncDecorator;
import com.example.designdemo.pay.context.PayContext;
import com.example.designdemo.pay.factory.AddFuncFactory;
import com.example.designdemo.pay.factory.PayFactory;
import com.example.designdemo.pay.strategy.PayStrategy;
import com.example.designdemo.pay.factory.StrategyFactory;
import com.example.designdemo.pay.pojo.PayBody;
import com.example.designdemo.pay.strategyEnum.StrategyEnum;/*** @Author: zhiwei Liao* @Date: 2022/9/25 11:27* @Description: 门面模式，最终只暴露门面即可，门面就是我们的超级封装*/public class StrategyFacade {// 定义一个map，将对应关系提前初始化好。// 双十一的时候，有大量的用户进行下单（千万级），就会造成千万级的pay接口的调用。// 很可惜，这部分代码里边有两个 new 关键字（new PayContext(payStrategy) 和 new AddFuncDecorator）。// 如果瞬时见。有几十万的并发进来，那么会创建几十万个 context对象和 addFunc对象，造成 年轻代的eden区的频繁对象创建// 虽然说调用完就进行了对象的垃圾收集，但是这么多的访问对象进来会造成，minorgc。// 1. 单例模式吗？PayContext创建是基于payStrategy，不止一种paycontext啊，用单例不行呀。 AddFuncDecorator 是基于PayContext// 创建的，PayContext 不止一种，AddFuncDecorator 也不止一种。// 2. 享元模式。享元模式是单例模式的一种思想升级。单例模式，针对的是同一种对象，没有任何不同的细节。而享元模式，针对多个对象。// 多个对象：同一种class，但是里边的属性有些许不同。PayContext是同一种对象吧？是的； PayContext 是不是有细节上的不同呢？是的，// payStrategy不同； 那么我们是否可以知道这个PayContext的种类数量呢？是的，目前有三种。 享元模式能够对这可控数量的有不同细节的//同一种class对象进行共享，保证我们的程序不频繁的创建对象。public static Boolean pay(PayBody payBody) {//获取我们的 策略枚举StrategyEnum strategyEnum = getStrategyEnum(payBody.getType());if(strategyEnum == null) {return false;}//获取我们的策略对象PayStrategy payStrategy = StrategyFactory.getPayStrategy(strategyEnum);//生成我们的策略上下文PayContext context = PayFactory.getPayContext(payStrategy); // 享元模式解决高并发下频繁创建对象的问题// 装饰一下 context，。立马多了一个功能// 我看这行代码啊，就不顺眼。代理模式搞他。AddFuncDecorator addFuncDecorator = (AddFuncDecorator) AddFuncFactory.getAddFunc(context); // 享元模式解决高并发下频繁创建对象的问题//进行扣款return addFuncDecorator.execute(payBody);}private static StrategyEnum getStrategyEnum(int type) {switch (type) {case 0:return StrategyEnum.ZfbPayStrategy;case 1:return StrategyEnum.WxPayStrategy;case 2:return StrategyEnum.BankPayStrategy;default:return null;}}}

创建AddFuncFactory

代码如下（示例）：

package com.example.designdemo.pay.factory;import com.example.designdemo.pay.additionalDecorator.AbstractAddFuncDecorator;
import com.example.designdemo.pay.additionalDecorator.AddFuncDecorator;
import com.example.designdemo.pay.context.PayContext;import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;/*** @Author: zhiwei Liao* @Date: 2022/9/25 20:53* @Description:*/
public class AddFuncFactory {// 工厂的目的是生产 AddFuncDecorator； 生产几个啊？ 多个：享元// key 应该是能够和 AbstractAddFuncDecorator 做成对应的东西。// 这个map最多保存是三个对象。public final static Map<PayContext, AbstractAddFuncDecorator> maps = new ConcurrentHashMap<>();public static AbstractAddFuncDecorator getAddFunc(PayContext payContext) {if(maps.get(payContext) == null) {AddFuncDecorator addFuncDecorator = new AddFuncDecorator(payContext);maps.put(payContext, addFuncDecorator);}return maps.get(payContext);}
}

创建PayFactory

代码如下（示例）：

package com.example.designdemo.pay.factory;import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import com.example.designdemo.pay.context.PayContext;
import com.example.designdemo.pay.strategy.PayStrategy;/*** @author zhiweiLiao<zhiwei.liao @ sgs.com>* @Description 享元模式解决高并发下频繁创建对象的问题* @Date create in 2022/9/28 0028 13:57*/
public class PayFactory {public final static Map<PayStrategy, PayContext> maps = new ConcurrentHashMap<>();public static PayContext getPayContext(PayStrategy payStrategy) {if(maps.get(payStrategy) == null) {PayContext payContext = new PayContext(payStrategy);maps.put(payStrategy, payContext);}return maps.get(payStrategy);}}

创建StrategyFactory

代码如下（示例）：

package com.example.designdemo.pay.factory;import com.example.designdemo.pay.strategy.PayStrategy;
import com.example.designdemo.pay.strategyEnum.StrategyEnum;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;/*** @Author: zhiwei Liao* @Date: 2022/9/25 10:53* @Description: 策略工厂 工厂类依靠策略枚举返回策略类 后面都不需要修改了，因为它是一个无状态的 使用饿汉单例模式创建*/public class StrategyFactory {private static final Map<String, PayStrategy> strategyMaps = new ConcurrentHashMap();public static PayStrategy getPayStrategy(StrategyEnum strategyEnum){PayStrategy payStrategy = strategyMaps.get(strategyEnum.getValue());try {payStrategy = (PayStrategy) Class.forName(strategyEnum.getValue()).newInstance();strategyMaps.put(strategyEnum.getValue(), payStrategy);} catch (Exception e) {//异常信息打印}return payStrategy;}}

创建AddFuncDecorator

代码如下（示例）：

package com.example.designdemo.pay.additionalDecorator;import com.example.designdemo.pay.context.AbstractPayContext;
import com.example.designdemo.pay.pojo.PayBody;/*** @Author: zhiwei Liao* @Date: 2022/9/25 20:53* @Description:abstractPayContext 不是共享的，因为有的小伙伴选择 zfb 支付，有的小伙伴选择wx支付，等等。。。*/
public class AddFuncDecorator extends AbstractAddFuncDecorator{public AddFuncDecorator(AbstractPayContext abstractPayContext) {super(abstractPayContext);}// 新活儿@Overridepublic void additionalFunction(PayBody payBody) { // 共享的，跟支付策略没有任何关系String product = payBody.getProduct();// 从db里边获取 product的详细信息。// 从配置中心（redis缓存）里获取产品的更新策略。// 根据策略更新用户平台币 或（和） 发放红包。System.out.println("更新平台币成功，发送红包到用户优惠券模块成功。");}@Overridepublic Boolean execute(PayBody payBody) { // 算共享的。共享的调用逻辑Boolean result = super.execute(payBody); //老活儿this.additionalFunction(payBody); // 新活儿. 新活儿的各种重试，失败补偿return result;}}

创建AbstractAddFuncDecorator

代码如下（示例）：

package com.example.designdemo.pay.additionalDecorator;import com.example.designdemo.pay.context.AbstractPayContext;
import com.example.designdemo.pay.pojo.PayBody;
/*** @Author: zhiwei Liao* @Date: 2022/9/25 20:53* @Description:*/
public abstract class AbstractAddFuncDecorator extends AbstractPayContext {// 这是我们的装饰器类。专门干装修的。 专门添加新功能的（平台币，红包）// 装饰的是谁啊？ 我作为一个称职的装饰器，我必须得知道装饰的是谁，不然我咋干活儿啊。private AbstractPayContext abstractPayContext = null;public AbstractAddFuncDecorator(AbstractPayContext abstractPayContext) {this.abstractPayContext = abstractPayContext;}// 开始干活儿//1. 老活儿。 支付。但是我又不能修改支付代码，也不能修改支付逻辑。@Overridepublic Boolean execute(PayBody payBody) {return abstractPayContext.execute(payBody);}//2. 老活儿不合适，没你装饰器照样能execute。 新活儿：平台币，红包）public abstract void additionalFunction(PayBody payBody);
}

创建StrategyEnum

代码如下（示例）：

package com.example.designdemo.pay.strategyEnum;
/*** @Author: zhiwei Liao* @Date: 2022/9/25 10:56* @Description: 准备使用反射*/public enum StrategyEnum {ZfbPayStrategy("com.example.designdemo.pay.strategy.ZfbPayStrategy"),WxPayStrategy("com.example.designdemo.pay.strategy.WxPayStrategy"),BankPayStrategy("com.example.designdemo.pay.strategy.BankPayStrategy");String value = "";StrategyEnum(String value){this.value = value;}public String getValue(){return this.value;}
}

校验是否正常工作