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Fegin client entry test

2022-06-25 23:20:00 【WhyLearnCode】

Fegin Client- Introductory quiz

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Fegin Client- Introductory quiz

1 Interface provider

1.1 To configure ：pom.yml and bootstrap.yml

1) pom.xml Add the following dependencies

artifactId	explain	edition
spring-cloud-starter-alibaba-nacos-discovery	nacos Registry dependent packages
spring-boot-starter-actuator	Monitoring checks
spring-cloud-starter-alibaba-nacos-config	nacos Configuration center depends on support
spring-cloud-dependencies	Spring Cloud begin	Greenwich.SR2
spring-cloud-alibaba-dependencies	Spring Cloud Alibaba begin	2.1.0.RELEASE

Pay attention to the version problem ,spring-boot 、spring-cloud as well as spring.cloud.alibaba
and The difference between
Main management version , It is useful for subclasses to inherit from the same parent class , Centrally manage dependent versions without adding dependencies , For the version defined therein , Son pom You don't have to inherit from your father pom Defined version . Medium jar Add directly to the project , Managing dependencies （ If there is a father pom, Son pom, Then son pom Can only passively accept the version of the parent class ）;

2) bootstrap.yml

bootstrap.yml and application.yml The difference between
a. Use spring cloud need bootstrap.yml Provide... Before the project loads server Configuration information , As boot configuration .

server:
  port: 9005
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/myqx?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
    username: root
    password: 1234
  application:
    name: itcast-map
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
      config:
        server-addr: localhost:8848

1.2 Provide the interface

@Autowired
private UserInfoService userInfoService;

@GetMapping("/get")
public List<UserInfo> findAll() {
    
    List<UserInfo> result = userInfoService.findAll();
    return result;
}

Only the configuration and interfaces are exposed here , The details are CURD Simple interface implementation , No need to pay attention. , Just know it's through

2 Service caller

2.1 To configure ：pom.yml and bootstrap.yml

No business dependencies are required compared to service providers , Such as mybatis-plus、mysql etc. , Also need to nacos Registry dependent packages 、 Monitoring checks 、nacos Configuration center dependency , You need to add remote calls and Feign rely on .

<properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <!-- Spring Cloud  Version information  --> <spring-cloud.version>Greenwich.SR2</spring-cloud.version> <!-- Spring Cloud Alibaba  Version information  --> <spring.cloud.alibaba.version>2.1.0.RELEASE</spring.cloud.alibaba.version>
</properties>
<!--  The parent project  -->
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.6.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<dependencyManagement>
    <dependencies>
        <!-- Spring Cloud begin--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>${spring-cloud.version}</version> <type>pom</type> <scope>import</scope> </dependency> <!-- Spring Cloud end--> <!-- Spring Cloud Alibaba begin--> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-alibaba-dependencies</artifactId> <version>${spring.cloud.alibaba.version}</version> <type>pom</type> <scope>import</scope> </dependency> <!-- Spring Cloud Alibaba end -->
    </dependencies>
</dependencyManagement>

<dependencies>
    <!--SpringMVC--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!-- tool kit --> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> </dependency> <!-- lombok --> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.10</version> <scope>provided</scope> </dependency> <!-- restTemplate  The remote invocation  --> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.5</version> </dependency> <!-- nacos Registry dependent packages  --> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency> <!--  Monitoring checks --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> <!-- nacos Configuration center depends on support  --> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId> </dependency>

    <!-- feign call  --> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency>
</dependencies>

2) bootstrap.yml

server:
  port: 9013

spring:
  application:
    name: itcast-nacos
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
      config:
        server-addr: localhost:8848

2.2 Start class

You need to add... On the startup class @SpringBootApplication、@EnableDiscoveryClient、@EnableFeignClients

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients    //  Open remote call 
public class NacosApplication {
    
    public static void main(String[] args) {
    
        SpringApplication.run(NacosApplication.class, args);
    }

}

2.3 Interface

With the interface caller Controller The difference between writing interfaces is , Service callers are used to create interface classes @FeignClien Annotation implementation

@FeignClien annotation
@FeignClient The common attributes of tags are as follows ：
- name： Appoint FeignClient The name of , If the project is used Ribbon,name The property will be used as the name of the microservice , For service discovery
- url: url Generally used for debugging , Can be specified manually @FeignClient The address of the call
- decode404: Happen when http 404 When it's wrong , If the word segment true, Would call decoder decode , Otherwise throw FeignException
- configuration: Feign Configuration class , You can customize Feign Of Encoder、Decoder、LogLevel、Contract
- fallback: Defines fault-tolerant handling classes , When the call to the remote interface fails or times out , The fault-tolerant logic of the corresponding interface is invoked ,fallback The specified class must be implemented @FeignClient Tagged interface
- fallbackFactory: Factory , Used to generate fallback Class example , With this property we can implement fault tolerance logic common to each interface , Reduce duplicate code
- path: Define the current FeignClient Unified prefix of
1、 The interface provider is in the registry .
If the service provider has registered with the registry , that name perhaps value The value of is ： Service provider's service name . One... Must be specified for all clients name perhaps value
@FeignClient(value=“run-product”,fallback = ProductClientServiceFallBack.class)
2、 A single one http Interface , The interface provider is not registered with the registry .
@FeignClient(name=“runClient11111”,url=“localhost:8001”)
here name The value of is : The name of the calling client .

@FeignClient(value = "itcast-map",fallback = UserHystrix.class)
public interface UserFegin {
    

    @GetMapping("user/get")
    public List<UserInfo> findAll();
}

2.4 Fault tolerant processing class

@Component
public class UserHystrix implements UserFegin {
    
@Override
public List<UserInfo> findAll() {
    
    return null;
	}
}

2.5 UserController

@RestController
@RequestMapping("/user")
public class UserController {
    
    @Autowired
    private RestTemplate restTemplate;

    @Autowired
    private UserFegin userFegin;

    /** *  Parameters  * @return */
    @GetMapping("/test006")
    public String feignClien() {
    
        List<UserInfo> all = userFegin.findAll();
        System.out.println(all);
        return "myqxin";
}