SpringCloud-OpenFeign-服务接口调用

是什么

把需要暴露的api使用接口来暴露，客户端需要调用的时候，直接查看这个接口中有没有就可以了

通用步骤

架构说明

common模块

common 引入 openfeign

新建服务接口类

@FeignClient(value = "cloud-payment-service") // 服务名
public interface PayFeignApi {@PostMapping("/pay/add")public Result<Integer> addPay(@RequestBody PayDTO payDTO);@GetMapping("/pay/get/{id}")public Result<PayDTO> getById(@PathVariable("id") Integer id); // 必须指明 PathVariable 的 value@GetMapping("/pay/getInfo")public Result<String> getInfo();
}

客户端

<dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

主启动类 @EnableFeignClients

使用

@RestController
public class OrderController {@Resourceprivate PayFeignApi payFeignApi;@GetMapping("/consumer/pay/add")public Result addOrder(PayDTO payDTO) {return payFeignApi.addPay(payDTO);}@GetMapping("/consumer/pay/get/{id}")public Result<PayDTO> getPayByOrderNo(@PathVariable("id") Integer id) {return payFeignApi.getById(id);}@GetMapping("/consumer/pay/getInfo")public Result<String> getInfoByConsul() {return payFeignApi.getInfo();}
}

最后一个案例可以看到，openfeign 天生支持负载均衡

OpenFeign高级特性

日志打印

// 日志记录级别@Beanpublic Logger.Level feignLoggerLevel() {return Logger.Level.FULL;}

超时控制

测试超时时间异常

@GetMapping("/consumer/pay/getInfo")public Result<String> getInfoByConsul() {Result<String> result = null;try {System.out.println("调用开始: " + DateUtil.now());result = payFeignApi.getInfo();} catch (Exception e) {e.printStackTrace();System.out.println("调用结束: " + DateUtil.now());Result.fail(ReturnCodeEnum.RC500.getCode(), e.getMessage());}return result;}

read-timeout 默认 60s

如何调整

全局配置

调整后测试，发现3s后就异常返回

手动配置(服务级别)

同时存在，细粒度的覆盖粗粒度的

重试机制

性能优化HttpClient5替换

<dependency><groupId>io.github.openfeign</groupId><artifactId>feign-hc5</artifactId><version>13.1</version>
</dependency>
<dependency><groupId>org.apache.httpcomponents.client5</groupId><artifactId>httpclient5</artifactId><version>5.3.1</version>
</dependency>

spring:cloud:openfeign:httpclient:hc5:enabled: true

HttpClient5 开启

替换以后

请求回应压缩

spring:cloud:openfeign:compression:request:enabled: truemime-types: text/xml,application/xml,application/jsonmin-request-size: 2048response:enabled: true