Spring Cloud Feign 高级应用

使用feign进行服务间的调用

服务提供者

(1)创建provider-service服务提供者,添加如下依赖:

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<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

(2)application.properties配置文件代码如下:

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server.port=9600
spring.application.name=provider-service
eureka.instance.prefer-ip-address=true
#配置注册中心地址
eureka.client.serviceUrl.defaultZone=http://zy:zy123@localhost:10025/eureka/

(3)启动主类添加@EnableDiscoveryClient

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@EnableDiscoveryClient
@SpringBootApplication
public class ProviderServiceApplication {

public static void main(String[] args) {
SpringApplication.run(ProviderServiceApplication.class, args);
}
}

(4)创建HelloController,添加一个hello方法

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@RestController
public class HelloController {

@RequestMapping("/hello")
public String hello(String name){
return "hello " + name;
}
}

服务消费者

(1)创建consumer-service服务提供者,添加如下依赖:

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<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<!-- 因为要使用feign调用其他服务,所以需要添加此依赖 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

(2)application.properties配置文件代码如下:

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server.port=9700
spring.application.name=consumer-service
eureka.instance.prefer-ip-address=true
# 配置注册中心地址
eureka.client.serviceUrl.defaultZone=http://zy:zy123@localhost:10025/eureka/

(3)启动主类添加@EnableDiscoveryClient@EnableFeignClients2个注解

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@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class ConsumerServiceApplication {

public static void main(String[] args) {
SpringApplication.run(ConsumerServiceApplication.class, args);
}
}

(4)创建一个接口HelloFeignService,调用服务提供者

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//name为服务提供者向注册中心注册的实例名
@FeignClient(name = "provider-service" )
public interface HelloFeignService {
//地址为服务提供者对外暴露的地址
@RequestMapping(value = "/hello", method = RequestMethod.GET)
String hello(@RequestParam("name") String name);
}

(5)创建IndexController控制器,注入feign,像本地方法一样调用服务提供者的服务

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@RestController
public class IndexController {

@Autowired
private HelloFeignService feignService;

@RequestMapping(value = "/hello" , method = RequestMethod.GET)
public String hello(String name){
return feignService.hello(name);
}
}

(6)启动2个项目,访问服务消费者 http://localhost:9700/hello?name=joe

feign开启Gzip压缩

Spring Cloud Feign支持对请求与响应的压缩,以提高通信效率,在服务消费者配置文件开启压缩支持和压缩文件的类型即可

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#feign 请求与响应的压缩
feign.compression.request.enabled=true
feign.compression.response.enabled=true
feign.compression.request.mime-types=text/xml,application/xml,application/json
feign.compression.request.min-request-size=2048

feign开启日志

feign开启日志有两种方式,一种是使用配置文件,一种是使用java代码,下面将介绍代码方式

创建FeignLogConfig类,添加一个LoggerBean

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@Configuration
public class FeignLogConfig {

/**
* 日志level有4个级别
* 1.NONE,不记录任何日志
* 2.BASIC,仅记录请求方法、URL以及响应状态码和执行时间
* 3.HEADRES,除了BASIC以外的还会记录请求和响应的头信息
* 4.FULL,所有
* @return
*/
@Bean
Logger.Level feignLogger(){
return Logger.Level.FULL;
}
}

feign替换JDK默认的URLConnection为okhttp

使用okhttp,能提高qps,因为okhttp有连接池和超时时间进行调优

(1)在服务消费者中,添加feign-okhttp依赖

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<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-okhttp</artifactId>
</dependency>

(2)在配置文件中,禁用默认的http,启用okhttp

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feign.httpclient.enabled=false
feign.okhttp.enabled=true

(3)创建OkHttpConfig类,添加okhttp的bean

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/**
* 配置okhttp与连接池
* ConnectionPool默认创建5个线程,保持5分钟长连接
*/
@Configuration
@ConditionalOnClass(Feign.class)
@AutoConfigureBefore(FeignAutoConfiguration.class)
public class OkHttpConfig {

@Bean
public okhttp3.OkHttpClient okHttpClient(){
return new okhttp3.OkHttpClient.Builder()
//设置连接超时
.connectTimeout(10, TimeUnit.SECONDS)
//设置读超时
.readTimeout(10, TimeUnit.SECONDS)
//设置写超时
.writeTimeout(10, TimeUnit.SECONDS)
//是否自动重连
.retryOnConnectionFailure(true)
.connectionPool(new ConnectionPool(10, 5L, TimeUnit.MINUTES))
.build();
}
}

feign超时设置

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# feign启用hystrix,才能熔断、降级
feign.hystrix.enabled=true

# hystrix的超时时间
hystrix.command.default.execution.timeout.enabled=true
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=10000

# ribbon的超时时间
ribbon.ReadTimeout=10000
ribbon.ConnectTimeout=10000

feign使用hystrix进行熔断、降级处理

上面的超时时间设置为10秒,把服务提供者sleep睡眠时间大于10秒,服务消费者就会触发hystrix,进行熔断保护

(1)改造服务提供者,让服务睡眠60秒

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@RequestMapping("/hello")
public String hello(String name){
try {
//睡眠60秒,测试feign的熔断、降级
Thread.sleep(60 * 1000);
}catch (Exception e){
e.printStackTrace();
}
return "hello " + name;
}

(2)改造服务消费者,添加feign的熔断、降级方法,feign的hystrix熔断降级很好实现,只要在FeignClient的fallback回滚方法中指定那个实现类即可

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@FeignClient(name = "provider-service", fallback = HelloFeignFallbackService.class)
public interface HelloFeignService {

@RequestMapping(value = "/hello", method = RequestMethod.GET)
String hello(@RequestParam("name") String name);
}

HelloFeignFallbackService代码如下:

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/**
* hystrix服务降级处理,防止因超时、异常等导致的服务调用雪崩
*/
@Service
public class HelloFeignFallbackService implements HelloFeignService {
@Override
public String hello(String name) {
return "未找到" + name;
}
}

(3)然后启动服务提供者与消费者,再访问 http://localhost:9700/hello?name=joe ,发现页面缓了10来秒,就直接返回了熔断方法中的内容,说明hystrix熔断降级成功

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