小傅哥 | 重学 Java 设计模式：实战策略模式「模拟多种营销类型优惠券，折扣金额计算策略场景」

.gitignore

@@ -34,3 +34,4 @@
 /itstack-demo-design-19-02/itstack-demo-design-19-02.iml
 /itstack-demo-design-19-01/itstack-demo-design-19-01.iml
 /itstack-demo-design-19-00/itstack-demo-design-19-00.iml
+/itstack-demo-design-20-01/itstack-demo-design-20-01.iml

itstack-demo-design-20-01/pom.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http:https://maven.apache.org/POM/4.0.0"
+ xmlns:xsi="http:https://www.w3.org/2001/XMLSchema-instance"
+ xsi:schemaLocation="http:https://maven.apache.org/POM/4.0.0 http:https://maven.apache.org/xsd/maven-4.0.0.xsd">
+ <parent>
+ <artifactId>itstack-demo-design</artifactId>
+ <groupId>org.itstack</groupId>
+ <version>1.0-SNAPSHOT</version>
+ </parent>
+ <modelVersion>4.0.0</modelVersion>
+
+ <artifactId>itstack-demo-design-20-01</artifactId>
+
+
+</project>

itstack-demo-design-20-01/src/main/java/org/itstack/demo/design/CouponDiscountService.java

@@ -0,0 +1,40 @@
+package org.itstack.demo.design;
+
+import java.math.BigDecimal;
+
+/**
+ * 博客：https://bugstack.cn - 沉淀、分享、成长，让自己和他人都能有所收获！
+ * 公众号：bugstack虫洞栈
+ * Create by 小傅哥(fustack) @2020
+ * 优惠券折扣计算接口
+ * <p>
+ * 优惠券类型；
+ * 1. 直减券
+ * 2. 满减券
+ * 3. 折扣券
+ * 4. n元购
+ */
+public class CouponDiscountService {
+
+ public double discountAmount(int type, double typeContent, double skuPrice, double typeExt) {
+ // 1. 直减券
+ if (1 == type) {
+ return skuPrice - typeContent;
+ }
+ // 2. 满减券
+ if (2 == type) {
+ if (skuPrice < typeExt) return skuPrice;
+ return skuPrice - typeContent;
+ }
+ // 3. 折扣券
+ if (3 == type) {
+ return skuPrice * typeContent;
+ }
+ // 4. n元购
+ if (4 == type) {
+ return typeContent;
+ }
+ return 0D;
+ }
+
+}

itstack-demo-design-20-02/pom.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http:https://maven.apache.org/POM/4.0.0"
+ xmlns:xsi="http:https://www.w3.org/2001/XMLSchema-instance"
+ xsi:schemaLocation="http:https://maven.apache.org/POM/4.0.0 http:https://maven.apache.org/xsd/maven-4.0.0.xsd">
+ <parent>
+ <artifactId>itstack-demo-design</artifactId>
+ <groupId>org.itstack</groupId>
+ <version>1.0-SNAPSHOT</version>
+ </parent>
+ <modelVersion>4.0.0</modelVersion>
+
+ <artifactId>itstack-demo-design-20-02</artifactId>
+
+
+</project>

itstack-demo-design-20-02/src/main/java/org/itstack/demo/design/Context.java

@@ -0,0 +1,22 @@
+package org.itstack.demo.design;
+
+import java.math.BigDecimal;
+
+/**
+ * 博客：https://bugstack.cn - 沉淀、分享、成长，让自己和他人都能有所收获！
+ * 公众号：bugstack虫洞栈
+ * Create by 小傅哥(fustack) @2020
+ */
+public class Context<T> {
+
+ private ICouponDiscount<T> couponDiscount;
+
+ public Context(ICouponDiscount<T> couponDiscount) {
+ this.couponDiscount = couponDiscount;
+ }
+
+ public BigDecimal discountAmount(T couponInfo, BigDecimal skuPrice) {
+ return couponDiscount.discountAmount(couponInfo, skuPrice);
+ }
+
+}

itstack-demo-design-20-02/src/main/java/org/itstack/demo/design/ICouponDiscount.java

@@ -0,0 +1,28 @@
+package org.itstack.demo.design;
+
+import java.math.BigDecimal;
+
+/**
+ * 博客：https://bugstack.cn - 沉淀、分享、成长，让自己和他人都能有所收获！
+ * 公众号：bugstack虫洞栈
+ * Create by 小傅哥(fustack) @2020
+ * <p>
+ * 优惠券折扣计算接口
+ * <p>
+ * 优惠券类型；
+ * 1. 直减券
+ * 2. 满减券
+ * 3. 折扣券
+ * 4. n元购
+ */
+public interface ICouponDiscount<T> {
+
+ /**
+ * 优惠券金额计算
+ * @param couponInfo 券折扣信息；直减、满减、折扣、N元购
+ * @param skuPrice sku金额
+ * @return 优惠后金额
+ */
+ BigDecimal discountAmount(T couponInfo, BigDecimal skuPrice);
+
+}

itstack-demo-design-20-02/src/main/java/org/itstack/demo/design/impl/MJCouponDiscount.java

@@ -0,0 +1,34 @@
+package org.itstack.demo.design.impl;
+
+import org.itstack.demo.design.ICouponDiscount;
+
+import java.math.BigDecimal;
+import java.util.Map;
+
+/**
+ * 博客：https://bugstack.cn - 沉淀、分享、成长，让自己和他人都能有所收获！
+ * 公众号：bugstack虫洞栈
+ * Create by 小傅哥(fustack) @2020
+ *
+ * 满减
+ */
+public class MJCouponDiscount implements ICouponDiscount<Map<String,String>> {
+
+ /**
+ * 满减计算
+ * 1. 判断满足x元后-n元，否则不减
+ * 2. 最低支付金额1元
+ */
+ public BigDecimal discountAmount(Map<String,String> couponInfo, BigDecimal skuPrice) {
+ String x = couponInfo.get("x");
+ String o = couponInfo.get("n");
+
+ // 小于商品金额条件的，直接返回商品原价
+ if (skuPrice.compareTo(new BigDecimal(x)) < 0) return skuPrice;
+ // 减去优惠金额判断
+ BigDecimal discountAmount = skuPrice.subtract(new BigDecimal(o));
+ if (discountAmount.compareTo(BigDecimal.ZERO) < 1) return BigDecimal.ONE;
+
+ return discountAmount;
+ }
+}

itstack-demo-design-20-02/src/main/java/org/itstack/demo/design/impl/NYGCouponDiscount.java

@@ -0,0 +1,24 @@
+package org.itstack.demo.design.impl;
+
+import org.itstack.demo.design.ICouponDiscount;
+
+import java.math.BigDecimal;
+
+/**
+ * 博客：https://bugstack.cn - 沉淀、分享、成长，让自己和他人都能有所收获！
+ * 公众号：bugstack虫洞栈
+ * Create by 小傅哥(fustack) @2020
+ *
+ * n元购买
+ */
+public class NYGCouponDiscount implements ICouponDiscount<Double> {
+
+ /**
+ * n元购购买
+ * 1. 无论原价多少钱都固定金额购买
+ */
+ public BigDecimal discountAmount(Double couponInfo, BigDecimal skuPrice) {
+ return new BigDecimal(couponInfo);
+ }
+
+}

itstack-demo-design-20-02/src/main/java/org/itstack/demo/design/impl/ZJCouponDiscount.java

@@ -0,0 +1,27 @@
+package org.itstack.demo.design.impl;
+
+import org.itstack.demo.design.ICouponDiscount;
+
+import java.math.BigDecimal;
+
+/**
+ * 博客：https://bugstack.cn - 沉淀、分享、成长，让自己和他人都能有所收获！
+ * 公众号：bugstack虫洞栈
+ * Create by 小傅哥(fustack) @2020
+ *
+ * 直减
+ */
+public class ZJCouponDiscount implements ICouponDiscount<Double> {
+
+ /**
+ * 直减计算
+ * 1. 使用商品价格减去优惠价格
+ * 2. 最低支付金额1元
+ */
+ public BigDecimal discountAmount(Double couponInfo, BigDecimal skuPrice) {
+ BigDecimal discountAmount = skuPrice.subtract(new BigDecimal(couponInfo));
+ if (discountAmount.compareTo(BigDecimal.ZERO) < 1) return BigDecimal.ONE;
+ return discountAmount;
+ }
+
+}

itstack-demo-design-20-02/src/main/java/org/itstack/demo/design/impl/ZKCouponDiscount.java

@@ -0,0 +1,29 @@
+package org.itstack.demo.design.impl;
+
+import org.itstack.demo.design.ICouponDiscount;
+
+import java.math.BigDecimal;
+
+/**
+ * 博客：https://bugstack.cn - 沉淀、分享、成长，让自己和他人都能有所收获！
+ * 公众号：bugstack虫洞栈
+ * Create by 小傅哥(fustack) @2020
+ *
+ * 折扣
+ */
+public class ZKCouponDiscount implements ICouponDiscount<Double> {
+
+
+ /**
+ * 折扣计算
+ * 1. 使用商品价格乘以折扣比例，为最后支付金额
+ * 2. 保留两位小数
+ * 3. 最低支付金额1元
+ */
+ public BigDecimal discountAmount(Double couponInfo, BigDecimal skuPrice) {
+ BigDecimal discountAmount = skuPrice.multiply(new BigDecimal(couponInfo)).setScale(2, BigDecimal.ROUND_HALF_UP);
+ if (discountAmount.compareTo(BigDecimal.ZERO) < 1) return BigDecimal.ONE;
+ return discountAmount;
+ }
+
+}

itstack-demo-design-20-02/src/test/java/org/itstack/demo/design/test/ApiTest.java

@@ -0,0 +1,61 @@
+package org.itstack.demo.design.test;
+
+import org.itstack.demo.design.Context;
+import org.itstack.demo.design.impl.MJCouponDiscount;
+import org.itstack.demo.design.impl.NYGCouponDiscount;
+import org.itstack.demo.design.impl.ZJCouponDiscount;
+import org.itstack.demo.design.impl.ZKCouponDiscount;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.math.BigDecimal;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * 博客：https://bugstack.cn - 沉淀、分享、成长，让自己和他人都能有所收获！
+ * 公众号：bugstack虫洞栈
+ * Create by 小傅哥(fustack) @2020
+ */
+public class ApiTest {
+
+ private Logger logger = LoggerFactory.getLogger(ApiTest.class);
+
+ @Test
+ public void test_zj() {
+ // 直减；100-10，商品100元
+ Context<Double> context = new Context<Double>(new ZJCouponDiscount());
+ BigDecimal discountAmount = context.discountAmount(10D, new BigDecimal(100));
+ logger.info("测试结果：直减优惠后金额 {}", discountAmount);
+ }
+
+ @Test
+ public void test_mj() {
+ // 满100减10，商品100元
+ Context<Map<String,String>> context = new Context<Map<String,String>>(new MJCouponDiscount());
+ Map<String,String> mapReq = new HashMap<String, String>();
+ mapReq.put("x","100");
+ mapReq.put("n","10");
+ BigDecimal discountAmount = context.discountAmount(mapReq, new BigDecimal(100));
+ logger.info("测试结果：满减优惠后金额 {}", discountAmount);
+ }
+
+
+ @Test
+ public void test_zk() {
+ // 折扣9折，商品100元
+ Context<Double> context = new Context<Double>(new ZKCouponDiscount());
+ BigDecimal discountAmount = context.discountAmount(0.9D, new BigDecimal(100));
+ logger.info("测试结果：折扣9折后金额 {}", discountAmount);
+ }
+
+ @Test
+ public void test_nyg() {
+ // n元购；100-10，商品100元
+ Context<Double> context = new Context<Double>(new NYGCouponDiscount());
+ BigDecimal discountAmount = context.discountAmount(90D, new BigDecimal(100));
+ logger.info("测试结果：n元购优惠后金额 {}", discountAmount);
+ }
+
+}

pom.xml

@@ -55,6 +55,8 @@
  <module>itstack-demo-design-19-00</module>
  <module>itstack-demo-design-19-01</module>
  <module>itstack-demo-design-19-02</module>
+ <module>itstack-demo-design-20-01</module>
+ <module>itstack-demo-design-20-02</module>
  </modules>
 
  <dependencies>