108 lines
3.3 KiB
Markdown
108 lines
3.3 KiB
Markdown
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---
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layout: pattern
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title: Aggregator Microservices
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folder: aggregator-microservices
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permalink: /patterns/aggregator-microservices/
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categories: Architectural
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tags:
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- Cloud distributed
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- Decoupling
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- Microservices
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---
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## 意图
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用户对聚合器服务进行一次调用，然后聚合器将调用每个相关的微服务。
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## 解释
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真实世界例子
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> 我们的网络市场需要有关产品及其当前库存的信息。 它调用聚合服务，聚合服务依次调用产品信息微服务和产品库存微服务，返回组合信息。
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通俗地说
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> 聚合器微服务从各种微服务中收集数据，并返回一个聚合数据以进行处理。
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Stack Overflow上说
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> 聚合器微服务调用多个服务以实现应用程序所需的功能。
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**程序示例**
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让我们从数据模型开始。 这是我们的`产品`。
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```java
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public class Product {
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private String title;
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private int productInventories;
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// getters and setters ->
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...
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}
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```
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接下来，我们将介绍我们的聚合器微服务。 它包含用于调用相应微服务的客户端`ProductInformationClient`和` ProductInventoryClient`。
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```java
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@RestController
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public class Aggregator {
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@Resource
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private ProductInformationClient informationClient;
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@Resource
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private ProductInventoryClient inventoryClient;
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@RequestMapping(path = "/product", method = RequestMethod.GET)
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public Product getProduct() {
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var product = new Product();
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var productTitle = informationClient.getProductTitle();
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var productInventory = inventoryClient.getProductInventories();
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//Fallback to error message
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product.setTitle(requireNonNullElse(productTitle, "Error: Fetching Product Title Failed"));
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//Fallback to default error inventory
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product.setProductInventories(requireNonNullElse(productInventory, -1));
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return product;
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}
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}
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```
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这是产品信息微服务的精华实现。 库存微服务类似，它只返回库存计数。
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```java
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@RestController
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public class InformationController {
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@RequestMapping(value = "/information", method = RequestMethod.GET)
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public String getProductTitle() {
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return "The Product Title.";
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}
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}
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```
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Now calling our `Aggregator` REST API returns the product information.
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现在调用我们的聚合器 REST API会返回产品信息。
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```bash
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curl http://localhost:50004/product
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{"title":"The Product Title.","productInventories":5}
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```
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## 类图
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## 适用性
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当需要各种微服务的统一API时，无论客户端设备如何，都可以使用Aggregator微服务模式。
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## 鸣谢
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* [Microservice Design Patterns](http://web.archive.org/web/20190705163602/http://blog.arungupta.me/microservice-design-patterns/)
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* [Microservices Patterns: With examples in Java](https://www.amazon.com/gp/product/1617294543/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=1617294543&linkId=8b4e570267bc5fb8b8189917b461dc60)
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* [Architectural Patterns: Uncover essential patterns in the most indispensable realm of enterprise architecture](https://www.amazon.com/gp/product/B077T7V8RC/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=B077T7V8RC&linkId=c34d204bfe1b277914b420189f09c1a4)
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