用springboot優(yōu)雅的實現(xiàn)設計模式--狀態(tài)機模式

在一些復雜的業(yè)務當中场刑，涉及到某個業(yè)務有多個狀態(tài)鳄乏，按照傳統(tǒng)寫法無非就是if else，其實還是有一種比較優(yōu)雅的實現(xiàn)方式区丑，就是設計模式中的狀態(tài)機模式拧粪。沒有spring之前雖然也能實現(xiàn)狀態(tài)機模式，但是并不優(yōu)雅沧侥。下面來說一個用springboot來實現(xiàn)狀態(tài)機模式的案例可霎。

舉一個例子，比如訂單：訂單當中涉及到多個狀態(tài)的跳轉正什，有的時候還需要對修改狀態(tài)前的邏輯進行判斷啥纸，這個時候用狀態(tài)機模式就是很好的實現(xiàn)号杏。

1婴氮、引入部分依賴

<groupId>org.example</groupId>
    <artifactId>order_demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <parent>
        <artifactId>spring-boot-parent</artifactId>
        <groupId>org.springframework.boot</groupId>
        <version>2.3.0.RELEASE</version>
    </parent>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.20</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

主要的包結構:

Snipaste_2021-06-09_22-35-07.png

2、訂單類：

/**
 * @version 1.0
 * @date 2021/6/9 21:33
 * 訂單類
 */
@AllArgsConstructor
@NoArgsConstructor
@Data
public class Order implements Serializable {
    /**
     * id
     */
    private Long id;
    /**
     * 金額
     */
    private BigDecimal price;
    /**
     * 狀態(tài)
     */
    private Integer status;
    /**
     * 創(chuàng)建時間
     */
    private Date createTime;
}

3盾致、創(chuàng)建訂單狀態(tài)處理超類

package org.example.bll;

import org.example.pojo.Order;

/**
 * @version 1.0
 * @date 2021/6/9 21:43
 * 訂單狀態(tài)處理超類
 */
public interface OrderState {
    /**
     * 原來狀態(tài)
     * @param newOrder 新訂單
     * @param oldOrder 老訂單
     */
    void handle(Order newOrder,Order oldOrder);
}

4主经、各個狀態(tài)處理類

package org.example.bll;

import org.example.pojo.Order;

/**
 * @version 1.0
 * @date 2021/6/9 21:46
 * 訂單各狀態(tài)處理
 */
public class OrderStateCommon implements OrderState {
    @Override
    public void handle(Order newOrder, Order oldOrder) {

    }

    /**
     * 生成日志
     *
     * @param order 訂單
     */
    public void buildOrderLog(Order order) {
        //保存日志
        System.out.println("保存日志訂單狀態(tài): " + order.getStatus());
    }
}

import org.example.pojo.Order;
import org.springframework.stereotype.Component;

import java.util.Objects;

/**
 * @version 1.0
 * @date 2021/6/9 21:52
 * 訂單狀態(tài): 1
 */
@Component(OrderStateFactory.ORDER_STATUS + 1)
public class OrderStateFor1 extends OrderStateCommon {
    @Override
    public void handle(Order newOrder, Order oldOrder) {
        if (Objects.isNull(oldOrder)){
            System.out.println("不做操作");
        }
        System.out.println("訂單狀態(tài):1 處理邏輯==>");
        //保存日志
        super.buildOrderLog(newOrder);
    }
}

package org.example.bll;

import org.example.pojo.Order;
import org.springframework.stereotype.Component;

/**
 * @version 1.0
 * @date 2021/6/9 21:52
 * 訂單狀態(tài): 2
 */
@Component(OrderStateFactory.ORDER_STATUS + 2)
public class OrderStateFor2 extends OrderStateCommon{
    @Override
    public void handle(Order newOrder, Order oldOrder) {
        System.out.println("訂單狀態(tài):2 處理邏輯==>");
        //保存日志
        super.buildOrderLog(newOrder);
    }
}

package org.example.bll;

import org.example.pojo.Order;
import org.springframework.stereotype.Component;

/**
 * @version 1.0
 * @date 2021/6/9 21:52
 * 訂單狀態(tài): 3
 */
@Component(OrderStateFactory.ORDER_STATUS + 3)
public class OrderStateFor3 extends OrderStateCommon{
    @Override
    public void handle(Order newOrder, Order oldOrder) {
        System.out.println("訂單狀態(tài):3 處理邏輯==>");
        //保存日志
        super.buildOrderLog(newOrder);
    }
}

5、主要工廠類獲取主要處理類

package org.example.bll;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * @author wenlinshan
 * @version 1.0
 * @date 2021/6/9 21:56
 */
@Component
public class OrderStateFactory {
    /**
     * 自定義bean名字前綴
     */
    public static final String ORDER_STATUS = "orderStatus";
    /**
     * 注入到容器里面
     */
    @Autowired
    Map<String, OrderState> states = new ConcurrentHashMap<>(4);

    /**
     * 獲取對應狀態(tài)的執(zhí)行類
     *
     * @param status 狀態(tài)
     * @return 具體狀態(tài)的執(zhí)行類
     */
    public OrderState getState(Integer status) {
        if (states.containsKey(ORDER_STATUS + status)) {
            return states.get(ORDER_STATUS + status);
        }
        throw new RuntimeException("未找到執(zhí)行狀態(tài)的類");
    }
}

6庭惜、主要的入口類代碼

package org.example.service.impl;

import org.example.bll.OrderState;
import org.example.bll.OrderStateFactory;
import org.example.pojo.Order;
import org.example.service.IOrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.Objects;

/**
 * @version 1.0
 * @date 2021/6/9 21:37
 */
@Service
public class OrderServiceImpl implements IOrderService {
    @Autowired
    private OrderStateFactory factory;
    @Override
    public void saveOrUpdateOrder(Order order) {
        //查找出原來的訂單
        Order oldOrder = this.getById(order.getId());
        if (Objects.isNull(oldOrder)) {
            //新增
            this.save(order);
            if (Objects.nonNull(order.getStatus())) {
                //調用狀態(tài)機
                factory.getState(order.getStatus()).handle(order,null);
            }
            return;
        }
        //修改
        OrderState orderState = Objects.isNull(order.getStatus()) ? factory.getState(oldOrder.getStatus()) : factory.getState(order.getStatus());
        orderState.handle(order,oldOrder);

    }

至此罩驻，所有的代碼都已實現(xiàn)，下面開始演示‘

7护赊、測試類：

package org.example;

import org.example.pojo.Order;
import org.example.service.IOrderService;
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;

import java.math.BigDecimal;
import java.util.Date;

/**
 * @version 1.0
 * @date 2021/6/9 22:03
 */
@RunWith(SpringRunner.class)
@SpringBootTest
public class OrderTest {
    @Autowired
    private IOrderService orderService;

    @Test
    public void testOrder1() {
        Order order = new Order(1L, BigDecimal.ONE, 2, new Date());
        orderService.saveOrUpdateOrder(order);
    }
    
}

運行結果：

Snipaste_2021-06-09_22-44-33.png