🍃 MongoDB 从零到生产

<!-- pom.xml --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-mongodb</artifact> </dependency> <!-- 如果用响应式（WebFlux）--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-mongodb-reactive</artifactId> </dependency>

# application.yml spring: data: mongodb: # 单节点连接 uri: mongodb://localhost:27017/milk_tea_shop # 副本集连接（推荐生产用） # uri: mongodb://user:pass@host1:27017,host2:27017,host3:27017/milk_tea_shop?replicaSet=rs0&authSource=admin # 连接池配置（重要！） # spring.data.mongodb.uri 不支持所有参数时，用下面的方式 # 更详细的配置（MongoClientSettings） spring: data: mongodb: host: localhost port: 27017 database: milk_tea_shop username: app_user password: ${MONGO_PASSWORD} authentication-database: admin

import org.springframework.data.annotation.Id; import org.springframework.data.mongodb.core.mapping.Document; import org.springframework.data.mongodb.core.mapping.Field; import java.time.LocalDateTime; import java.util.List; @Document(collection = "orders") // 映射到 orders 集合 public class Order { @Id // MongoDB 的 _id 字段 private String id; @Field("order_no") // 自定义字段名（默认用 Java 字段名） private String orderNo; private String status; private Double totalAmount; // 内嵌对象 private CustomerInfo customer; private List<OrderItem> items; private LocalDateTime createdAt; private LocalDateTime updatedAt; // getter/setter 省略... } // 内嵌的对象不需要 @Document 注解 public class CustomerInfo { private String name; private String phone; } public class OrderItem { private String product; private Double price; private Integer qty; }

import org.springframework.data.mongodb.core.MongoTemplate; import org.springframework.data.mongodb.core.query.Criteria; import org.springframework.data.mongodb.core.query.Query; import org.springframework.data.mongodb.core.query.Update; import org.springframework.stereotype.Service; import java.util.List; @Service public class OrderService { private final MongoTemplate mongoTemplate; public OrderService(MongoTemplate mongoTemplate) { this.mongoTemplate = mongoTemplate; } // ===== 查询 ===== // 按状态查订单 public List<Order> findByStatus(String status) { Query query = new Query(Criteria.where("status").is(status)); return mongoTemplate.find(query, Order.class); } // 组合条件：状态 + 金额范围 + 时间 public List<Order> findPaidOrders(Double minAmount, LocalDateTime since) { Query query = new Query(); query.addCriteria(Criteria.where("status").is("paid") .and("totalAmount").gte(minAmount) .and("createdAt").gte(since)); query.with(Sort.by(Sort.Direction.DESC, "totalAmount")); query.limit(50); return mongoTemplate.find(query, Order.class); } // 查内嵌字段 public List<Order> findByCustomerName(String name) { Query query = new Query( Criteria.where("customer.name").is(name) ); return mongoTemplate.find(query, Order.class); } // ===== 更新 ===== public void updateStatus(String orderNo, String newStatus) { Query query = new Query(Criteria.where("orderNo").is(orderNo)); Update update = new Update(); update.set("status", newStatus); update.set("updatedAt", LocalDateTime.now()); mongoTemplate.updateFirst(query, update, Order.class); } // 数组操作：往订单里追加商品 public void addItem(String orderNo, OrderItem item) { Query query = new Query(Criteria.where("orderNo").is(orderNo)); Update update = new Update(); update.push("items", item); // 追加到数组 update.inc("totalAmount", item.getPrice()); // 金额增加 mongoTemplate.updateFirst(query, update, Order.class); } }

import org.springframework.data.mongodb.repository.MongoRepository; import java.util.List; import java.util.Optional; // 只要继承 MongoRepository，常用方法自动实现 public interface OrderRepository extends MongoRepository<Order, String> { // 按方法名自动生成查询（Derived Query） List<Order> findByStatus(String status); List<Order> findByStatusAndTotalAmountGreaterThan(String status, Double amount); Optional<Order> findByOrderNo(String orderNo); List<Order> findByCustomerNameOrderByCreatedAtDesc(String name); // 自定义查询（@Query） @Query("{ 'status': ?0, 'items.product': ?1 }") List<Order> findByStatusAndProductName(String status, String productName); }

import org.springframework.data.mongodb.core.aggregation.*; import static org.springframework.data.mongodb.core.aggregation.Aggregation.*; public List<ProductStats> getProductStats() { Aggregation aggregation = newAggregation( // $match: 过滤已支付 match(Criteria.where("status").is("paid")), // $unwind: 展开商品数组 unwind("items"), // $group: 按商品名分组统计 group("items.product") .sum("items.qty").as("totalQty") .sum( ArithmeticOperators.Multiply .valueOf("items.price") .multiplyBy("items.qty") ).as("totalRevenue") .count().as("orderCount"), // $sort: 按收入降序 sort(Sort.Direction.DESC, "totalRevenue"), // $project: 重命名字段 project("totalQty", "totalRevenue", "orderCount") .and("_id").as("product") .andExclude("_id") ); AggregationResults<ProductStats> results = mongoTemplate.aggregate(aggregation, "orders", ProductStats.class); return results.getMappedResults(); }