OpenFeign入门以及超时控制

OpenFeign入门

​ 跟着yang哥的视频学，来简单做一下入门笔记,新手使用Markdown，如果有写的不对的地方请多多指教^_

• 什么是openFeign

  • openFeign是一个微服务调用框架，主要作用在消费者端，即调用服务。

  • 是个声明式的web服务客户端，让编写web服务客户端变得更加容易，只需创建一个接口并在接口上添加注解即可–>@FeignClient,即只需要提供一个与provider服务一模一样的接口，并加上@GetMapping/@PostMapping，Feign就会帮我们调用这个ProVider的方法

  • SpringCloud对Feign进行了封装，指出Spring mvc标准注解以及HttpMessageConverters。

• OpenFeign的入门案例

  • 入门案例所需环境IDEA+eureka(做服务注册与发现,现已停更可以改用zookeeper/consul)+OpenFeign+SpringCloud H+mybatis

  • 一、provider服务

    • maven的依赖

    <dependencies>
            
            <dependency>
                <groupId>org.springframework.cloudgroupId>
                <artifactId>spring-cloud-starter-zipkinartifactId>
            dependency>
    
            <dependency>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-starter-webartifactId>
            dependency>
            
            <dependency>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-starter-actuatorartifactId>
            dependency>
            <dependency>
                <groupId>org.mybatis.spring.bootgroupId>
                <artifactId>mybatis-spring-boot-starterartifactId>
            dependency>
            
            <dependency>
                <groupId>org.springframework.cloudgroupId>
                <artifactId>spring-cloud-starter-netflix-eureka-clientartifactId>
            dependency>
            <dependency>
                <groupId>com.alibabagroupId>
                <artifactId>druid-spring-boot-starterartifactId>
                
            dependency>
            
            <dependency>
                <groupId>mysqlgroupId>
                <artifactId>mysql-connector-javaartifactId>
            dependency>
            
            <dependency>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-starter-jdbcartifactId>
            dependency>
            
    
            <dependency>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-devtoolsartifactId>
                <scope>runtimescope>
                <optional>trueoptional>
            dependency>
            <dependency>
                <groupId>org.projectlombokgroupId>
                <artifactId>lombokartifactId>
                <optional>trueoptional>
            dependency>
            <dependency>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-starter-testartifactId>
                <scope>testscope>
            dependency>
            <dependency>
                <groupId>com.psfgroupId>
                <artifactId>cloud-api-commonsartifactId>
                <version>${project.version}version>
            dependency>
    
            <dependency>
                <groupId>org.springframework.cloudgroupId>
                <artifactId>spring-cloud-starter-netflix-eureka-clientartifactId>
            dependency>
    
        dependencies>
    

    • 配置yml

      server:
        port: 8001
      #配置名字
      spring:
        application:
          name: cloud-payment-service
        datasource:
          # 当前数据源操作类型
          type: com.alibaba.druid.pool.DruidDataSource
          # mysql驱动类
          driver-class-name: com.mysql.jdbc.Driver
          username: root
          password: 123
          url: jdbc:mysql://localhost:3306/db2019?serverTimezone=UTC&useUnicode=true&characterEncoding=utf8
      
      mybatis:
      	//在resources下创建一个Mapper目录管理mybatis的xml
        mapper-locations: classpath*:mapper/*.xml
        type-aliases-package: com.psf.springcloud.entities
      
      eureka:
        client:
          register-with-eureka: true
          fetch-registry: true
          service-url:
      #       单击版
      #      defaultZone: http://localhost:7001/eureka
      #      集群版
            defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka  #集群版
        #配置访问7001端口的时候显示的信息
        instance:
          instance-id: payment8001
          #显示ip地址
          prefer-ip-address: true
          lease-renewal-interval-in-seconds:  1
          lease-expiration-duration-in-seconds:  2
      

    • 编写主启动类

      @SpringBootApplication
      //使注解生效
      @EnableEurekaClient
      @EnableDiscoveryClient
      public class PaymentMain8001 {
                 
          public static void main(String[] args) {
                 
              SpringApplication.run(PaymentMain8001.class,args);
          }
      }
      

    • 编写dao

      @Mapper
      public interface PaymentDao {
                 
      
          public int create(Payment payment);
      
          public Payment getPaymentById(@Param("id") Long id);
      
      }
      

    • 编写service(这里还要编写一个实现类，就不写出)

      public interface PaymentService {
                 
          public int create(Payment payment);
      
          public Payment getPaymentById(@Param("id") Long id);
      }
      

    • 编写controller

      @RestController
      @Slf4j
      public class PaymentController {
                 
           @Autowired
          private PaymentService paymentService;
      
          @Value("${server.port}")
          private String serverPort;
          
          /**CommonResult是个实体类，如果没看过yang哥的视频的同学可以参考下面属性去创建,主要属性有
          private Integer code;
          private String message;
          private T       data;
          */
          @GetMapping("/payment/get/{id}")
          public CommonResult getPaymentById(@PathVariable("id") Long id){
                 
              Payment payment = paymentService.getPaymentById(id);
              log.info("*****查询结果"+payment);
      
              if (payment !=null){
                 
                  return new CommonResult(200,"查询成功,端口号:"+serverPort,payment);
              }else {
                 
                  return new CommonResult(444,"没有对应记录，查询id"+id,null);
              }
          }
      }
      

    • controller写完

  • 二、customer服务

    • 由于customer是调用provider端的，所以可以不用dao层,service层也有一点变化

    • pom其实就是多了个OpenFeign的starter

      <dependency>
          <groupId>org.springframework.cloudgroupId>
          <artifactId>spring-cloud-starter-openfeignartifactId>
      dependency>
      

    • 配置yml

      server:
        port: 80
      eureka:
        client:
          register-with-eureka: false
          service-url:
          #这里配置的是集群
            defaultZone: http://eureka7001.com:7001/eureka, http://eureka7002.com:7002/eureka
      

    • 主启动类

      @SpringBootApplication
      @EnableFeignClients
      public class OrderFeignMain80 {
                 
          public static void main(String[] args) {
                 
              SpringApplication.run(OrderFeignMain80.class);
          }
      }
      

    • 编写service

      //要添加component注解
      @Component
      //这里要添加一个新的注解
      @FeignClient(value = "cloud-payment-service")
      public interface PaymentFeignService {
                 
          @GetMapping("/payment/get/{id}")
          public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id);
      
      }
      

    • 编写controlelr

      @RestController
      @Slf4j
      public class OrderFeignController {
                 
      
          @Resource
          private PaymentFeignService paymentFeignService;
      
          @GetMapping("/customer/payment/get/{id}")
          public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id){
                 
              //这里也是只需要调用service的方法就行
              return paymentFeignService.getPaymentById(id);
          }
      }
      

    • 到这里customer服务也写完了

  • 三、discovery and regist(注册与发现)服务

    • pom

      <dependency>
          <groupId>org.springframework.cloudgroupId>
          <artifactId>spring-cloud-starter-netflix-eureka-serverartifactId>
      dependency>
      

    • yml

      server:
        port: 7001
      
      ##搭建集群的话：相互守望，相互注册
      eureka:
        #初始化主机名字
        instance:
          hostname: eureka7001.com  #eureka服务端的实例名字
        client:
          fetch-registry: false
          #不注册自己
          register-with-eureka: false
          #注册的ur,开启集群模式，需要指向对方
          service-url:
            defaultZone: http://eureka7002.com:7002/eureka/
      #      defaultZone: http://eureka7001.com:7001/eureka/
        #关闭自我保护机制
        server:
          enable-self-preservation: false
          eviction-interval-timer-in-ms: 2000
      

    • 配置主启动类

      @SpringBootApplication
      //这里要引入一个注解，才能使eureka生效
      @EnableEurekaServer
      public class EurekaMain7001 {
                 
          public static void main(String[] args) {
                 
              SpringApplication.run(EurekaMain7001.class);
          }
      }
      

    • 到这里就完全结束啦

    • 先把注册服务启动，再把消费者与provider服务启动

    • 访问localhost:/customer/payment/get/1 就能看到信息

• openFeign超时控制

  • 意思就是在provider端，需要处理3秒钟，但是customer端只能等1秒钟，这样就会报错

  • status 404 reading PaymentFeignService#paymentFeignTimeout()

  • 案例演示：

  • provider的controller添加如下方法

    //模拟超时控制
    @GetMapping("/payment/feign/timeout")
    public String paymentFeignTimeout(){
             
        try {
             
            //模拟处理三秒钟 
            TimeUnit.SECONDS.sleep(3);
        } catch (InterruptedException e) {
             
            e.printStackTrace();
        }
        return serverPort;
    }
    

  • customer的service添加上面方法的一个接口

  • customer的controller添加接口的方法

    @GetMapping("/customer/payment/feign/timeout")
    public String paymentFeignTimeout(){
             
        //openFeign底层是ribbon，客户端默认等待1秒钟，但是支付端要处理三秒钟
        return paymentFeignService.paymentFeignTimeout();
    }
    

  • 那我们需要解决这种问题,feign的超时控制是由ribbon控制的，所以我们可以在yml中配置一下超时控制。解决某些请求确实要超过默认时间，把默认等待时间和默认处理时间调整一致

  • 在customer的yml添加

    #与server同级
    ribbon:
      ReadTimeout:  5000
      ConnectTimeout: 5000
    

• openFeign日志打印功能

  • 对feign接口的调用情况进行监控和输出

  • 配置yml

    logging:
      level:
        com.atguigu.springcloud.service.PaymentFeignService: debug
    

  • 配置config类

    @Configuration
    public class FeignConfig {
             
        /**
        *feign的日志打印有5中
        FULL:除了HEAD，全部打印
        BASE:仅记录请求方法,URL,响应装代码
        HEAD:除BASE，打印
        NONE:不打印
        */
        @Bean
        Logger.Level feignLoggerLevel(){
             
            return Logger.Level.FULL;
        }
    }