515 lines
12 KiB
Markdown
515 lines
12 KiB
Markdown
# Nacos注册中心
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## 注册中心
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### 服务发现
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发现服务信息。
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```java
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@SpringBootTest()
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public class DiscoveryTest {
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@Autowired
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private DiscoveryClient discoveryClient;
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@Autowired
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private NacosDiscoveryClient nacosDiscoveryClient;
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@Test
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void discoveryClientTest() {
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for (String service : discoveryClient.getServices()) {
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System.out.println(service);
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for (ServiceInstance instance : discoveryClient.getInstances(service)) {
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System.out.println("IP地址：" + instance.getHost());
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System.out.println("端口号" + instance.getPort());
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}
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}
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System.out.println("----------------------------------------------");
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// 两个方式一样，DiscoveryClient 是 Spring自带的 NacosDiscoveryClient是 Nacos
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for (String service : nacosDiscoveryClient.getServices()) {
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System.out.println(service);
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for (ServiceInstance instance : nacosDiscoveryClient.getInstances(service)) {
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System.out.println("IP地址：" + instance.getHost());
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System.out.println("端口号" + instance.getPort());
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}
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}
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}
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}
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```
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### 远程调用
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订单模块调用远程商品模块，使用了nacos，可以使用`RestTemplate`，其中`RestTemplate`是线程安全的，只要注册一次全局都是可以使用。
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**RestTemplate源码**
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继承了`InterceptingHttpAccessor`，在`InterceptingHttpAccessor`中，使用了单例模式。
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```java
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public ClientHttpRequestFactory getRequestFactory() {
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List<ClientHttpRequestInterceptor> interceptors = this.getInterceptors();
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if (!CollectionUtils.isEmpty(interceptors)) {
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ClientHttpRequestFactory factory = this.interceptingRequestFactory;
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if (factory == null) {
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factory = new InterceptingClientHttpRequestFactory(super.getRequestFactory(), interceptors);
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this.interceptingRequestFactory = factory;
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}
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return factory;
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} else {
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return super.getRequestFactory();
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}
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}
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```
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#### 实现远程调用
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##### 普通方式调用
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注册`RestTemplate`
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```java
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@Bean
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public RestTemplate restTemplate() {
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return new RestTemplate();
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}
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```
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如果我们的服务启动了多个，在下面代码中即使一个服务宕机也可以做到远程调用。
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```java
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private Product getProductFromRemote(Long productId) {
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// 获取商品服务所有及其的 IP+port
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List<ServiceInstance> instances = discoveryClient.getInstances("service-product");
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ServiceInstance instance = instances.get(0);
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// 远程URL
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String url = "http://" + instance.getHost() + ":" + instance.getPort() + "/api/product/" + productId;
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// 2. 远程发送请求
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log.info("远程调用：{}", url);
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return restTemplate.getForObject(url, Product.class);
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}
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```
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##### 负载均衡调用
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注册`RestTemplate`
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```java
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@Bean
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public RestTemplate restTemplate() {
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return new RestTemplate();
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}
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```
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使用负载均衡`LoadBalancerClient`，通过负载均衡算法动态调用远程服务。
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```java
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/**
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* 远程调用商品模块 --- 负载均衡
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*
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* @param productId 商品id
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* @return 商品对象
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*/
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private Product getProductFromRemoteWithLoadBalancer(Long productId) {
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// 1. 获取商品服务所有及其的 IP+port
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ServiceInstance instance = loadBalancerClient.choose("service-product");
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// 远程URL
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String url = "http://" + instance.getHost() + ":" + instance.getPort() + "/api/product/" + productId;
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// 2. 远程发送请求
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log.info("负载均衡远程调用：{}", url);
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return restTemplate.getForObject(url, Product.class);
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}
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```
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##### 负载均衡注解调用
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> [!TIP]
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>
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> 如果远程注册中心宕机是否可以调用？
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>
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> 调用过：远程调用不在依赖注册中心，可以通过。
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>
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> 没调用过：第一次发起远程调用；不能通过。
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在`RestTemplate`上加上`@LoadBalanced`注解使用负载均衡。
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```java
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@Bean
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@LoadBalanced
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public RestTemplate restTemplate() {
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return new RestTemplate();
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}
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```
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在实际的调用中并不需要再显式调用，将URL替换成服务名称即可。
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```java
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/**
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* 远程调用商品模块 --- 负载均衡注解调用
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*
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* @param productId 商品id
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* @return 商品对象
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*/
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private Product getProductFromRemoteWithLoadBalancerAnnotation(Long productId) {
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// 远程URL，实现动态替换
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String url = "http://service-product/api/product/" + productId;
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// 远程发送请求
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log.info("负载均衡注解调用：{}", url);
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return restTemplate.getForObject(url, Product.class);
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}
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```
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## 按需加载
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### 数据隔离架构
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### 命名空间管理
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#### 创建命名空间
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> [!TIP]
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> 预配置的命名空间示例可在项目 `samples/namespace-config` 目录下找到。
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建议创建以下标准命名空间：
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- `dev` - 开发环境
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- `test` - 测试环境
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- `prod` - 生产环境
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**操作步骤**：
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1. 进入Nacos控制台命名空间管理
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2. 点击"新建命名空间"
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3. 填写命名空间信息（ID和名称）
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#### 配置管理
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**开发环境配置示例**：
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1. 基础配置：
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```yaml
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order:
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timeout: 1min
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auto-confirm: 1h
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```
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2. 数据库配置：
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```yaml
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order:
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db-url: jdbc:mysql://dev-db:3306/order_dev
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```
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#### 命名空间克隆
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通过克隆功能快速创建相似环境的命名空间：
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### 动态环境配置
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#### Spring Boot 配置方案
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**基础配置**：
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```yaml
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server:
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port: 8000
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spring:
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application:
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name: service-order
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profiles:
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active: dev
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cloud:
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nacos:
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server-addr: ${NACOS_HOST:192.168.95.135}:8848
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config:
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namespace: ${spring.profiles.active:dev} # 动态匹配当前profile
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group: DEFAULT_GROUP
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```
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**多环境配置加载**：
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```yaml
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spring:
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config:
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import:
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- optional:nacos:service-order.yml
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- optional:nacos:common.yml?group=order
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- optional:nacos:database.yml?group=order
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```
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> [!NOTE]
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> 使用`optional:`前缀可避免配置不存在时启动失败
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### 配置读取实现
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**配置类**：
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```java
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@Configuration
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@ConfigurationProperties(prefix = "order")
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@Getter
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@Setter
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public class OrderProperties {
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private String timeout;
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private String autoConfirm;
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private String dbUrl; // 自动映射db-url
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}
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```
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**REST接口**：
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```java
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@RestController
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@RequestMapping("/api/order")
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@RequiredArgsConstructor
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public class OrderController {
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private final OrderProperties orderProperties;
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@GetMapping("/config")
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public Map<String, String> getConfig() {
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return Map.of(
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"timeout", orderProperties.getTimeout(),
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"autoConfirm", orderProperties.getAutoConfirm(),
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"dbUrl", orderProperties.getDbUrl()
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);
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}
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}
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```
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### 按需加载策略
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#### 多环境差异化配置
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```yaml
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spring:
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profiles:
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active: prod # 可通过启动参数覆盖
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---
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# 生产环境配置
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spring:
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config:
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import:
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- nacos:service-order-prod.yml
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- nacos:common-prod.yml?group=order
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activate:
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on-profile: prod
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---
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# 开发环境配置
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spring:
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config:
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import:
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- nacos:service-order-dev.yml
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- nacos:database-dev.yml?group=order
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activate:
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on-profile: dev
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---
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# 测试环境配置
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spring:
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config:
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import:
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- nacos:service-order-test.yml
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- nacos:database-test.yml?group=order
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activate:
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on-profile: test
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```
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## OpenFeign
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### 基础配置
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#### 依赖引入
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```xml
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<dependency>
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<groupId>org.springframework.cloud</groupId>
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<artifactId>spring-cloud-starter-openfeign</artifactId>
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<version>${spring-cloud.version}</version>
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</dependency>
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```
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#### 启用Feign客户端
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```java
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@SpringBootApplication
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@EnableDiscoveryClient
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@EnableFeignClients(basePackages = "com.yourpackage.feign")
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public class OrderServiceApplication {
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public static void main(String[] args) {
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SpringApplication.run(OrderServiceApplication.class, args);
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}
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}
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```
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### Feign客户端使用
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#### 服务间调用
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**Feign客户端定义**：
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```java
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@FeignClient(
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value = "service-product",
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path = "/api/product",
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configuration = ProductFeignConfig.class
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)
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public interface ProductFeignClient {
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@GetMapping("/{id}")
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ResponseEntity<Product> getProductById(@PathVariable("id") Long productId);
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@PostMapping
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ResponseEntity<Void> createProduct(@RequestBody Product product);
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}
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```
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**服务调用示例**：
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```java
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@Service
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@RequiredArgsConstructor
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public class OrderService {
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private final ProductFeignClient productFeignClient;
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public Order createOrder(Long productId, Long userId) {
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// 使用Feign客户端调用远程服务
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ResponseEntity<Product> response = productFeignClient.getProductById(productId);
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if (!response.getStatusCode().is2xxSuccessful()) {
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throw new RuntimeException("商品服务调用失败");
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}
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Product product = response.getBody();
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Order order = new Order();
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// 订单业务逻辑处理...
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return order;
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}
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}
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```
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#### 第三方服务调用
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```java
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@FeignClient(
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name = "bunny-client",
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url = "${external.bunny.api.url}",
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configuration = ExternalFeignConfig.class
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)
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public interface BunnyFeignClient {
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@PostMapping("/login")
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ResponseEntity<String> login(@RequestBody LoginDto loginDto);
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}
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```
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**测试用例**：
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```java
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@SpringBootTest
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public class BunnyFeignClientTest {
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@Autowired
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private BunnyFeignClient bunnyFeignClient;
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@Test
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void testLogin() {
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LoginDto loginDto = new LoginDto("bunny", "admin123", "default");
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ResponseEntity<String> response = bunnyFeignClient.login(loginDto);
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assertThat(response.getStatusCode()).isEqualTo(HttpStatus.OK);
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System.out.println("登录响应: " + response.getBody());
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}
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}
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```
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### 负载均衡对比
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#### 客户端负载均衡 vs 服务端负载均衡
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| 特性 | 客户端负载均衡 (OpenFeign) | 服务端负载均衡 (Nginx等) |
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| ------------ | -------------------------- | ------------------------ |
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| **实现位置** | 客户端实现 | 服务端实现 |
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| **依赖关系** | 需要服务注册中心 | 不依赖注册中心 |
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| **性能** | 直接调用，减少网络跳转 | 需要经过代理服务器 |
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| **灵活性** | 可定制负载均衡策略 | 配置相对固定 |
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| **服务发现** | 集成服务发现机制 | 需要手动维护服务列表 |
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| **适用场景** | 微服务内部调用 | 对外暴露API或跨系统调用 |
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### 高级配置
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#### 日志配置
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**application.yml**:
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```yaml
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logging:
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level:
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org.springframework.cloud.openfeign: DEBUG
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com.yourpackage.feign: DEBUG
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```
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**Java配置**：
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```java
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public class FeignConfig {
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@Bean
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Logger.Level feignLoggerLevel() {
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return Logger.Level.FULL; // NONE, BASIC, HEADERS, FULL
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}
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}
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```
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#### 超时与重试配置
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**application-feign.yml**:
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```yaml
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spring:
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cloud:
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openfeign:
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client:
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config:
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default: # 全局默认配置
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connect-timeout: 2000
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read-timeout: 5000
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logger-level: basic
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service-product: # 特定服务配置
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connect-timeout: 3000
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read-timeout: 10000
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```
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**重试机制配置**：
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```java
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@Bean
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public Retryer feignRetryer() {
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// 重试间隔100ms，最大间隔1s，最大尝试次数3次
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return new Retryer.Default(100, 1000, 3);
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}
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```
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