后端：增加 cart 系统

cart/cart-service-api/pom.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>cart</artifactId>
+        <groupId>cn.iocoder.mall</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>cart-service-api</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>cn.iocoder.mall</groupId>
+            <artifactId>common-framework</artifactId>
+            <version>1.0-SNAPSHOT</version>
+        </dependency>
+
+        <dependency>
+            <groupId>javax.validation</groupId>
+            <artifactId>validation-api</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.mapstruct</groupId>
+            <artifactId>mapstruct</artifactId> <!-- use mapstruct-jdk8 for Java 8 or higher -->
+        </dependency>
+        <dependency>
+            <groupId>org.mapstruct</groupId>
+            <artifactId>mapstruct-jdk8</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+        </dependency>
+    </dependencies>
+
+</project>

cart/cart-service-api/src/main/java/cn/iocoder/mall/cart/api/CartService.java

@@ -0,0 +1,4 @@
+package cn.iocoder.mall.cart.api;
+
+public interface CartService {
+}

cart/cart-service-api/src/main/java/cn/iocoder/mall/cart/api/constant/CartErrorCodeEnum.java

@@ -0,0 +1,28 @@
+package cn.iocoder.mall.cart.api.constant;
+
+/**
+ * 错误码枚举类
+ *
+ * 购物车系统，使用 1-005-000-000 段
+ */
+public enum CartErrorCodeEnum {
+
+    ;
+
+    private final int code;
+    private final String message;
+
+    CartErrorCodeEnum(int code, String message) {
+        this.code = code;
+        this.message = message;
+    }
+
+    public int getCode() {
+        return code;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+}