springboot使用策略模式实现一个基本的促销

• 策略模式

定义了算法族，分别封装起来，让它们之间可以互相替换，

此模式让算法的变化独立于使用算法的客户

源码:https://github.com/youxiu326/sb_promotion.git

• 实体层

一共三个实体，分别为商品实体，促销实体，促销结果实体

商品实体定义了商品的销售价 优惠金额 优惠后金额 数量。。。

促销实体定义了促销类型 名称 参与该促销的商品集合

package com.youxiu326.entity;

import java.io.Serializable;
import java.math.BigDecimal;

/**
 * 商品:
 *
 * <br>优惠金额    <span color="red">discountAmount</span>
 * <br>优惠后价格 -1(默认等于销售金额) <span color="red">finalAmount</span>
 * <br>销售价       <span color="red">amount</span>
 *
 */
public class Product implements Serializable {

    private String code;

    private String name;

    /**
     * 销售价
     */
    private BigDecimal amount = BigDecimal.ZERO;

    /**
     * 优惠了多少金额
     */
    private BigDecimal discountAmount = BigDecimal.ZERO;

    /**
     * 优惠后金额
     */
    private BigDecimal finalAmount = new BigDecimal("-1");

    private Integer quantity;

    public Product(){}

    public Product(String code, String name, BigDecimal amount, Integer quantity) {
        this.code = code;
        this.name = name;
        this.amount = amount;
        this.quantity = quantity;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public BigDecimal getAmount() {
        return amount;
    }

    public double getAmountDouble(){
        return amount.doubleValue();
    }

    public void setAmount(BigDecimal amount) {
        this.amount = amount;
    }

    public Integer getQuantity() {
        return quantity;
    }

    public void setQuantity(Integer quantity) {
        this.quantity = quantity;
    }

    public BigDecimal getDiscountAmount() {
        return discountAmount;
    }

    public void setDiscountAmount(BigDecimal discountAmount) {
        this.discountAmount = discountAmount;
    }

    /**
     * 优惠后金额(默认等于交易金额)
     * @return
     */
    public BigDecimal getFinalAmount() {
        if(finalAmount.compareTo(new BigDecimal("-1"))==0) {
            finalAmount = amount;
        }
        return finalAmount;
    }

    public void setFinalAmount(BigDecimal finalAmount) {
        this.finalAmount = finalAmount;
    }
}

Product.java

package com.youxiu326.entity;

import java.io.Serializable;
import java.util.List;

/**
 * 促销实体类
 */
public class Promotion implements Serializable {

    /**
     *  <span color="red">促销类型:</span>
     *  <br>FREEONE  免最低一件
     *  <br>REBATE   八折
     *  <br>REDUCE   满100减20
     */
    public static enum Type{
        FREEONE,REBATE,REDUCE
    }

    private Type type;

    private String name;

    /**
     * 哪些商品应用促销
     */
    private List<Product> products;

    public Promotion(){}
    public Promotion(Type type, String name,List<Product> products) {
        this.type = type;
        this.name = name;
        this.products = products;
    }

    public Type getType() {
        return type;
    }

    public void setType(Type type) {
        this.type = type;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List<Product> getProducts() {
        return products;
    }

    public void setProducts(List<Product> products) {
        this.products = products;
    }
}

Promotion.java

package com.youxiu326.entity;

import java.io.Serializable;

/**
 * 促销结果
 */
public class PromotionResult implements Serializable {

    private String name;

    private Promotion.Type type;

    private Object result;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Promotion.Type getType() {
        return type;
    }

    public void setType(Promotion.Type type) {
        this.type = type;
    }

    public Object getResult() {
        return result;
    }

    public void setResult(Object result) {
        this.result = result;
    }
}

PromotionResult.java

package com.youxiu326.exception;

/**
 * 自定义异常
 */
public class ServiceException extends Exception {

    private Exception exception;

    public ServiceException(String message, Exception exception) {
        super(message);
        this.exception = exception;
    }

    public ServiceException(String message) {
        this(message, null);
    }

    public ServiceException(Exception exception) {
        this(null, exception);
    }

    public Exception getException() {
        return exception;
    }

    public Exception getRootCause() {
        if (exception instanceof ServiceException) {
            return ((ServiceException) exception).getRootCause();
        }
        return exception == null ? this : exception;
    }

    @Override
    public String toString() {
        if (exception instanceof ServiceException) {
            return ((ServiceException) exception).toString();
        }
        return exception == null ? super.toString() : exception.toString();
    }
} 

ServiceException.java

• 促销实体类

定义了一个抽象类 PromotionStrategy.java

定义了三个促销策略:

/**
 * 满足价格大于等于500
 * <br>减免价格最低一件商品促销
 */
@Component
public class FreeOneStrategy extends PromotionStrategy

/**
 * 满足大于200
 * <br>八折促销
 */
@Component
public class RebateStrategy extends PromotionStrategy 

/**
 * 满足满100
 * <br>减10促销
 */
@Component
public class ReduceStrategy extends PromotionStrategy

package com.youxiu326.abst;

import com.youxiu326.entity.Product;
import com.youxiu326.entity.Promotion;
import com.youxiu326.entity.PromotionResult;
import java.math.BigDecimal;
import java.util.List;

/**
 * 促销抽象类
 * 定义公共方法，让子类继承
 * 定义抽象方法，让子类实现
 */
public abstract class PromotionStrategy {

    public abstract Promotion.Type getType();

    /**
     * 定义执行促销方法
     * @param promotion 促销
     * @param products  参加促销的商品集合
     * @return
     */
    public abstract List<PromotionResult> execute(Promotion promotion, List<Product> products);

    /*
    //加法
    BigDecimal result1 = num1.add(num2);
    //减法
    BigDecimal result2 = num1.subtract(num2);
    //乘法
    BigDecimal result3 = num1.multiply(num2);
    //除法
    BigDecimal result5 = num2.divide(num1,20,BigDecimal.ROUND_HALF_UP);
    //绝对值
    BigDecimal result4 = num3.abs();

    比较大小
    结果是:   -1：小于；   0 ：等于；   1 ：大于；
    BigDecimal b1 = new BigDecimal("-121454125453.145");
    if(b1.compareTo(BigDecimal.ZERO)==-1) {
        System.out.println("金额为负数！");
    }
    */

    //优惠金额    discountAmount
    //优惠后价格 -1(默认等于销售金额) finalAmount
    //销售价       amount

    /**
     * <span color="red">平摊优惠金额</span>
     * @param products
     * @param disAmount
     */
    protected void sharedAmount(List<Product> products,BigDecimal disAmount){

        //计算总金额
        double totalAmountTemp = products.stream().mapToDouble(it->(
                it.getFinalAmount().multiply(new BigDecimal(it.getQuantity().toString()))).doubleValue()
        ).sum();

        //总金额
        BigDecimal totalAmount = new BigDecimal(totalAmountTemp+"");
        //已分摊金额
        BigDecimal sharedAmount = new BigDecimal("0");;

        //平摊金额到明细
        for(int i=0;i<products.size();i++) {
            Product product = products.get(i);
            if(i == products.size() - 1) {
                //② 如果是最后一件商品 ，将剩余优惠金额计算到这个商品内
                //例如:
                // 商品001 销售价10 数量1      商品002 销售价20 数量2     商品001,002 总共优惠了5元
                // 商品001 已经确定可优惠1元
                // 那么最后一个商品002 可以优惠 6-1 5元

                product.setDiscountAmount(product.getDiscountAmount().add(disAmount).subtract(sharedAmount));
            }else {
                //该商品总数量
                BigDecimal quantity = new BigDecimal(product.getQuantity().toString());

                //① 将总优惠金额 * (该商品销售价/总销售价) 得出该商品所占优惠金额
                // 例如:
                // 商品001 销售价10 数量1      商品002 销售价20 数量2     商品001,002 总共优惠了5元
                // 商品001可优惠金额= 5*(10*1/50)     1元
                // 商品002可优惠金额= 5*(20*2/50)     4元

                //得出该商品可优惠金额
                BigDecimal itemDisAmount = disAmount.multiply(
                        (product.getAmount().multiply(quantity).divide(totalAmount,2,BigDecimal.ROUND_HALF_UP))
                );

                product.setDiscountAmount(product.getDiscountAmount().add(itemDisAmount));

                sharedAmount =sharedAmount.add(itemDisAmount);
            }
        }

        // ③计算出 商品优惠后的价格 finalAmount
        products.stream().forEach(it->{
            BigDecimal quantity = new BigDecimal(it.getQuantity().toString());
            it.setFinalAmount(it.getAmount().multiply(quantity).subtract(it.getDiscountAmount()));
        });
    }
} 

package com.youxiu326.strategy;

import com.youxiu326.abst.PromotionStrategy;
import com.youxiu326.entity.Product;
import com.youxiu326.entity.Promotion;
import com.youxiu326.entity.PromotionResult;
import org.springframework.stereotype.Component;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;
import java.util.OptionalDouble;

/**
 * 满足价格大于等于500
 * <br>减免价格最低一件商品促销
 */
@Component
public class FreeOneStrategy extends PromotionStrategy {

    /**
     * 指定促销类型为：FREEONE
     * @return
     */
    @Override
    public Promotion.Type getType() {
        return Promotion.Type.FREEONE;
    }

    @Override
    public List<PromotionResult> execute(Promotion promotion, List<Product> products) {

        List<PromotionResult> results = new ArrayList<PromotionResult>();

        //计算总金额 总数量
        double totalAmount = products.stream().mapToDouble(it->(
                (it.getAmount().multiply(new BigDecimal(it.getQuantity().toString())))).subtract(it.getDiscountAmount()).doubleValue()
        ).sum();
        int totalQuantity =  products.stream().mapToInt(it->it.getQuantity()).sum();

        //TODO 这儿简单处理定死了规则
        //不满足促销规则的返回空促销
        if (totalAmount<500 || totalQuantity<=1){
            return results;
        }

        //获得可优惠金额
        double reduceAmount = products.stream().mapToDouble(Product::getAmountDouble).min().orElse(0);

        //平摊金额
        sharedAmount(products, new BigDecimal(reduceAmount+""));

        //创建减免促销信息
        PromotionResult result = new PromotionResult();
        result.setName(promotion.getName());
        result.setType(Promotion.Type.FREEONE);
        result.setResult(reduceAmount);
        results.add(result);

        return results;
    }
}

FreeOneStrategy.java

package com.youxiu326.strategy;

import com.youxiu326.abst.PromotionStrategy;
import com.youxiu326.entity.Product;
import com.youxiu326.entity.Promotion;
import com.youxiu326.entity.PromotionResult;
import org.springframework.stereotype.Component;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;

/**
 * 满足大于200
 * <br>八折促销
 */
@Component
public class RebateStrategy extends PromotionStrategy {

    /**
     * 指定促销类型为：REBATE
     * @return
     */
    @Override
    public Promotion.Type getType() {
        return Promotion.Type.REBATE;
    }

    @Override
    public List<PromotionResult> execute(Promotion promotion, List<Product> products) {

        List<PromotionResult> results = new ArrayList<PromotionResult>();

        //计算总金额 总数量
        double totalAmount = products.stream().mapToDouble(it->(
                (it.getAmount().multiply(new BigDecimal(it.getQuantity().toString())))).subtract(it.getDiscountAmount()).doubleValue()
        ).sum();
        int totalQuantity =  products.stream().mapToInt(it->it.getQuantity()).sum();

        //TODO 这儿简单处理定死了规则
        //不满足促销规则的返回空促销
        if (totalAmount<200){
            return results;
        }

        //获得可优惠金额
        double reduceAmount = totalAmount * 0.2;

        //平摊金额
        sharedAmount(products, new BigDecimal(reduceAmount+""));

        //创建减免促销信息
        PromotionResult result = new PromotionResult();
        result.setName(promotion.getName());
        result.setType(Promotion.Type.REBATE);
        result.setResult(reduceAmount);
        results.add(result);

        return results;
    }

} 

RebateStrategy.java

package com.youxiu326.strategy;

import com.youxiu326.abst.PromotionStrategy;
import com.youxiu326.entity.Product;
import com.youxiu326.entity.Promotion;
import com.youxiu326.entity.PromotionResult;
import org.springframework.stereotype.Component;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;

/**
 * 满足满100
 * <br>减10促销
 */
@Component
public class ReduceStrategy extends PromotionStrategy {

    /**
     * 指定促销类型为：REDUCE
     * @return
     */
    @Override
    public Promotion.Type getType() {
        return Promotion.Type.REDUCE;
    }

    @Override
    public List<PromotionResult> execute(Promotion promotion, List<Product> products) {

        List<PromotionResult> results = new ArrayList<>();

        //计算总金额 总数量
        double totalAmount = products.stream().mapToDouble(it->(
                (it.getAmount().multiply(new BigDecimal(it.getQuantity().toString())))).subtract(it.getDiscountAmount()).doubleValue()
        ).sum();
        int totalQuantity =  products.stream().mapToInt(it->it.getQuantity()).sum();

        //TODO 这儿简单处理定死了规则
        //不满足促销规则的返回空促销
        if (totalAmount<100){
            return results;
        }

        //获得可优惠金额
        double reduceAmount = 10;

        //平摊金额
        sharedAmount(products, new BigDecimal(reduceAmount+""));

        //创建减免促销信息
        PromotionResult result = new PromotionResult();
        result.setName(promotion.getName());
        result.setType(Promotion.Type.REDUCE);
        result.setResult(reduceAmount);
        results.add(result);

        return results;
    }

} 

ReduceStrategy.java

package com.youxiu326.context;

import com.youxiu326.abst.PromotionStrategy;
import com.youxiu326.entity.Product;
import com.youxiu326.entity.Promotion;
import com.youxiu326.entity.PromotionResult;
import com.youxiu326.exception.ServiceException;
import java.util.Collection;
import java.util.List;

/**
 * 促销上下文
 */
public class PromotionContext {

    /**
     * 促销策略
     */
    private PromotionStrategy strategy;

    /**
     * 当前促销
     */
    private Promotion promotion;

    public static Collection<PromotionStrategy> strategys;

    public PromotionContext(){}

    public PromotionContext(Promotion promotion) throws ServiceException {

        this.promotion = promotion;
        //初始化促销列表
        if(strategys == null)throw new ServiceException("无可用促销");

        //根据传入的促销 找到对应的促销策略 【strategy】
        strategy = strategys.stream().filter(it->it.getType() == promotion.getType()).findFirst().orElse(null);

        if(strategy == null) throw new ServiceException("找不到符合促销类型");
    }

    public List<PromotionResult> execute(List<Product> products) throws ServiceException{
        return strategy.execute(promotion, products);
    }

    public Collection<PromotionStrategy> getStrategys() {
        return strategys;
    }

    public void setStrategys(Collection<PromotionStrategy> strategys) {
        PromotionContext.strategys = strategys;
    }
}

• 促销service

处理促销业务逻辑

package com.youxiu326.service;

import com.youxiu326.entity.Product;
import com.youxiu326.entity.Promotion;
import com.youxiu326.entity.PromotionResult;
import com.youxiu326.exception.ServiceException;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;
import java.util.List;
import java.util.Map;

public interface PromotionService {

    /**
     * <span color="red">结算方法</span>
     * <br>结算对象包含:
     * <br>1.商品优惠价格
     * <br>2.优惠后最终价格
     * <br>3.优惠信息
     * @param products 要结算的商品集合
     * @return Object 返回结算后的对象
     */
    public Map<String,Object> settlement(List<Product> products) throws ServiceException;

    /**
     * 查询可用的促销
     * @return
     */
    public List<Promotion> findUsablePromotions();

    /**
     * 过滤出可以参加指定促销的商品
     * @param promotion 指定促销
     * @param products 要过滤的商品集合
     * @return 返回过滤后的商品集合
     */
    public List<Product> filterProduct(Promotion promotion, List<Product> products);

    /**
     * 执行促销
     * @param promotions 促销集合
     * @param products 商品集合
     * @return
     */
    public List<PromotionResult> execute(List<Promotion> promotions, List<Product> products) throws ServiceException;

} 

package com.youxiu326.service.impl;

import com.youxiu326.abst.PromotionStrategy;
import com.youxiu326.context.PromotionContext;
import com.youxiu326.entity.Product;
import com.youxiu326.entity.Promotion;
import com.youxiu326.entity.PromotionResult;
import com.youxiu326.exception.ServiceException;
import com.youxiu326.service.PromotionService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Service;
import javax.annotation.PostConstruct;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * 促销service
 */
@Service
public class PromotionServiceImpl implements PromotionService {

    private static final Logger LOGGER = LoggerFactory.getLogger(PromotionServiceImpl.class);

    //@Autowired
    //private ContextStartup contextStartup;

    @Autowired
    private ApplicationContext application;

    /**
     *  被@PostConstruct修饰的方法会在服务器加载Servlet的时候运行，并且只会被服务器调用一次，
     *  <br>类似于Serclet的inti()方法
     *  <br>被@PostConstruct修饰的方法会在构造函数之后，init()方法之前运行
     */
    @PostConstruct
    public void init() {
        PromotionContext.strategys =  application.getBeansOfType(PromotionStrategy.class).values();
    }

    @Override
    public Map<String,Object> settlement(List<Product> products) throws ServiceException{

        Map<String,Object> resultMap = new HashMap<>();

        //查询可用促销
        List<Promotion> promotions = findUsablePromotions();
        //执行促销
        List<PromotionResult> result = execute(promotions,products);

        //返回促销结果 与商品
        resultMap.put("promotionResult", result);
        resultMap.put("products", products);
        return resultMap;
    }

    /**
     * 执行促销
     * @param promotions 促销集合
     * @param products 商品集合
     * @return
     */
    @Override
    public List<PromotionResult> execute(List<Promotion> promotions, List<Product> products) throws ServiceException {
        LOGGER.info("促销开始执行 促销数量:{} 商品数量:{}",promotions.size(),products.size());

        products.stream().forEach(it->LOGGER.info("执行促销商品信息->编号:{} 价格:{} 数量:{}",it.getCode(),it.getAmount(),it.getQuantity()));

        //返回促销结果
        List<PromotionResult> promotionResults = new ArrayList<PromotionResult>();

        //遍历执行促销
        for (Promotion promotion : promotions) {

            //根据传入的促销 得到对应的促销上下文
            PromotionContext context  = new PromotionContext(promotion);

            //过滤出可以参加该促销的商品
            List<Product> filterProductList = filterProduct(promotion, products);

            //根据策略模式 执行先对应的促销规则，返回促销结果
            List<PromotionResult> result = context.execute(filterProductList);
            if (result!=null){
                promotionResults.addAll(result);
            }

        }

        //TODO 如果有的促销参加多次，应该要进行一定处理，只取一个即可

        LOGGER.info("促销执行结束");
        return promotionResults;
    }

    /**
     * 查询可用的促销
     * @return
     */
    @Override
    public List<Promotion> findUsablePromotions(){
        //TODO 这儿你可以直接查询数据库

        List<Promotion> promotions = new ArrayList<>();
        Promotion p1 = new Promotion(Promotion.Type.FREEONE,"价格大于等于500免最低一件",null);
        Promotion p2 = new Promotion(Promotion.Type.REBATE,"大于200八折",null);
        Promotion p3 = new Promotion(Promotion.Type.REDUCE,"满100减10",null);
        promotions.add(p1);
        promotions.add(p2);
        promotions.add(p3);
        LOGGER.info("查询到可用促销数量：{}",promotions.size());
        return promotions;
    }

    /**
     * 过滤出可以参加指定促销的商品
     * @param promotion 指定促销
     * @param products 要过滤的商品集合
     * @return 返回过滤后的商品集合
     */
    @Override
    public List<Product> filterProduct(Promotion promotion, List<Product> products){
        List<Product> list = new ArrayList<Product>();

        products.stream().forEach(it->{
            if (isMatching(promotion, it)) {
                list.add(it);
            }
        });

        return list;
    }

    /**
     * 判断该商品是否可以参加该促销
     * @param promotion
     * @param product
     * @return
     */
    private boolean isMatching(Promotion promotion, Product product) {
        //TODO 这里你应该查询数据库 1.看满足该促销的商品中是否包含该商品，2.如果该促销未设置商品默认所有商品都满足

        List<Product> products = null;

        //没有 所以商品都满足参加该促销的要求 返回true
        if(products == null || products.size() == 0)return true;

        //如果该商品在该促销商品集合内 则返回true 否则返回false
        long count = products.stream().filter(it->it.getCode().equals(product.getCode())).count();

        return count>0?true:false;
    }

}

• Junit

package com.youxiu326;

import com.youxiu326.entity.Product;
import com.youxiu326.exception.ServiceException;
import com.youxiu326.service.PromotionService;
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.ArrayList;
import java.util.List;
import java.util.Map;

@RunWith(SpringRunner.class)
@SpringBootTest
public class SbPromotionApplicationTests {

    @Autowired
    PromotionService service;

    @Test
    public void contextLoads() throws ServiceException {

        List<Product> products = new ArrayList<>();

        Product p1 = new Product("YX001", "牙刷", new BigDecimal("50"), 2);
        Product p2 = new Product("YX002", "电视", new BigDecimal("200"), 2);
        Product p3 = new Product("YX003", "圆珠笔", new BigDecimal("20"), 2);
        Product p4 = new Product("YX004", "水杯", new BigDecimal("60"), 1);
        Product p5 = new Product("YX005", "充电宝", new BigDecimal("400"), 1);
        /*products.add(p1);
        products.add(p2);
        products.add(p3);
        products.add(p4);*/
        products.add(p5);

        Map<String, Object> result = service.settlement(products);

        System.out.println(result);

    }

}

• 为了方便 写了一个简易页面

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <base th:href="${#httpServletRequest.getContextPath()+'/'}">
    <meta charset="UTF-8">
    <title>springboot+策略模式 实现简单促销</title>
</head>
<body>
<h2>提交商品</h2>

<body>

<table>
    <tr>
        <td>商品名称</td>
        <td>商品价格</td>
        <td>商品数量</td>
        <td>操作</td>
    </tr>
    <tr>
        <td><input id="name" /></td>
        <td><input id="amount" type="number" /></td>
        <td><input id="quantity" type="number" /></td>
        <td><input type="button" value="添加该商品" onclick="data()"/></td>
    </tr>
</table>

<h6>购物车商品</h6>
<div width="400px" height="400px" id="showShoop"></div>

<br>
<input  type="button" onclick="sub()" value="将这些商品进行促销"/>
<br>

<h6>参加促销信息展示</h6>
<div width="400px" height="400px" id="showPro"></div>

<h6>已添加商品信息展示</h6>
<table>
    <tr>
        <td>商品编号</td>
        <td>商品名称</td>
        <td>商品数量</td>
        <td>优惠后总价</td>
        <td>总优惠金额</td>
    </tr>
    <tbody id="showTab"></tbody>
</table>

</body>

<script src="/jquery-1.11.3.min.js"></script>
<script>

    var products = [];
    var num = 1;
    <!-- 准备数据 -->
    function data(){
        var name = $("#name").val();
        var amount = $("#amount").val();
        var quantity = $("#quantity").val();
        if(name=="" || amount=="" || quantity=="" || name==undefined || amount==undefined || quantity==undefined ){
            alert("商品格式有误");
            return ;
        }
        var code = "youxiu-"+ num;
        num=num+1;
        var product = {"code":code,"name":name,"amount":amount,"quantity":quantity};
        products.push(product);
        console.log(products);

        var em = "<span>"+product.name+"--"+product.quantity+"--"+product.amount+"</span><br>";
        $("#showShoop").append(em);
    }

    function sub(){
        if(products.length<=0){
            alert("请添加商品");
            retur;
        }
        $.ajax({
            type: 'POST',
            url: "/data",
            data: JSON.stringify(products),
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function(map){
                if(map==null){
                    alert("出错了");
                }
                var promotionResult = map.promotionResult;
                var result = map.products;
                console.log("促销结果:");
                console.log(promotionResult);
                console.log();
                console.log("促销后商品信息:");
                console.log(result);

                //促销信息展示
                $("#showPro").empty();
                for(var i=0;i<promotionResult.length;i++){
                    var em = "<span>"+promotionResult[i].name+"------"+promotionResult[i].result+"</span><br>";
                    $("#showPro").append(em);
                }

                //促销商品展示
                $("#showTab").empty();
                for(var i=0;i<result.length;i++){
                    var em = "<tr><td>"+result[i].code+"</td><td>"+result[i].name+"</td><td>"+result[i].quantity+"</td><td>"+result[i].finalAmount+"</td><td>"+result[i].discountAmount+"</td></tr>";
                    $("#showTab").append(em);
                }
            },
            error:function(map){
                alert(map);
                console.log(map);
            }
        });
    }

</script>

</html>

package com.youxiu326.controller;

import com.youxiu326.entity.Product;
import com.youxiu326.exception.ServiceException;
import com.youxiu326.service.PromotionService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import java.util.List;
import java.util.Map;

/**
 * 促销controller
 */
@Controller
public class PromotionCtrl {

    @Autowired
    private PromotionService service;

    @GetMapping("/index")
    public String index(){
        return "/index";
    }

    @PostMapping("/data")
    @ResponseBody
    public Map data(@RequestBody List<Product> products){
        Map map = null;
        try {
            map = service.settlement(products);
        } catch (ServiceException e) {
            return null;
        }
        return map;
    }

}

演示地址:http://promotion.youxiu326.xin

源码:https://github.com/youxiu326/sb_promotion.git