Feign声明式HTTP客户端

作者: WebGiser | 来源:发表于2021-09-25 12:13 被阅读0次

1、项目结构

1632542563(1).png

2、pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.13.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.geovis</groupId>
    <artifactId>usercenter</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>usercenter</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencyManagement>
        <!--SpringBoot整合Spring Cloud-->
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Greenwich.SR1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--SpringBoot整合Spring Cloud Alibaba-->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>0.9.0.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>


    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--服务发现依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!--openfeign 声明式http调用-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <dependency>
            <groupId>io.github.openfeign</groupId>
            <artifactId>feign-httpclient</artifactId>
        </dependency>


        <!--        <dependency>
                    <groupId>org.mybatis.spring.boot</groupId>
                    <artifactId>mybatis-spring-boot-starter</artifactId>
                    <version>2.2.0</version>
                </dependency>-->

        <!--通用mapper依赖-->
        <dependency>
            <groupId>tk.mybatis</groupId>
            <artifactId>mapper-spring-boot-starter</artifactId>
            <version>2.1.5</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <jvmArguments>-Dfile.encoding=UTF-8</jvmArguments>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.6</version>
                <configuration>
                    <configurationFile>
                        ${basedir}/src/main/resources/generator/generatorConfig.xml
                    </configurationFile>
                    <overwrite>true</overwrite>
                    <verbose>true</verbose>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>mysql</groupId>
                        <artifactId>mysql-connector-java</artifactId>
                        <version>8.0.19</version>
                    </dependency>
                    <dependency>
                        <groupId>tk.mybatis</groupId>
                        <artifactId>mapper</artifactId>
                        <version>4.1.5</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>
</project>

3、UsercenterApplication.java主类

package com.geovis.usercenter;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
import tk.mybatis.spring.annotation.MapperScan;

@EnableFeignClients
@MapperScan("com.geovis.usercenter")
@SpringBootApplication
public class UsercenterApplication {
    public static void main(String[] args) {
        SpringApplication.run(UsercenterApplication.class, args);
    }
}

4、application.properties

server.port=8080

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://192.168.1.13:3306/user_center?characterEncoding=UTF8&serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=123456

# 服务名称尽量用-，不要用_或特殊字符
spring.application.name=user-center
# nacos服务中心地址
spring.cloud.nacos.discovery.server-addr=localhost:8848
# 指定微服务实例所在的命名空间ID
spring.cloud.nacos.discovery.namespace=476e087f-6df4-499a-af4c-9dc933293655
# 指定微服务实例所在的集群名称
spring.cloud.nacos.discovery.cluster-name=NanJing

# ribbon负载均衡细粒度控制
# 饥饿加载(解决第一次访问缓慢问题)
ribbon.eager-load.enabled=true
ribbon.eager-load.clients=content-center
# 局部配置
content-center.ribbon.NFLoadBalanceRuleClassName=com.geovis.usercenter.configuration.NacosWeightedRule

# feign
# feign日志配置（NONE、BASIC、HEADERS、FULL）
logging.level.com.geovis.usercenter.feignclient.ContentCenterFeignClient = debug
# 让feign使用apache httpclient请求，而不是默认的urlconnection
feign.httpclient.enabled=true
# feign的最大连接数
feign.httpclient.max-connections=200
# feign单个路径的最大连接数
feign.httpclient.max-connections-per-route=50
# 采用配置文件的方式控制feign的日志级别
#feign.client.config.content-center.loggerLevel = basic

5、configuration/ContentCenterFeignConfiguration.java

java代码方式细粒度控制 feign日志级别

package com.geovis.usercenter.configuration;


import feign.Logger;
import org.springframework.context.annotation.Bean;


/*
* 设置feign的日志级别：NONE、BASIC、HEADERS、FULL
* */
public class ContentCenterFeignConfiguration {
    @Bean
    public Logger.Level level(){
        return Logger.Level.BASIC;
    }
}

6、feignclient/ContentCenterFeignClient.java

package com.geovis.usercenter.feignclient;


import com.geovis.usercenter.configuration.ContentCenterFeignConfiguration;
import com.geovis.usercenter.domain.dto.ShareDto;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.cloud.openfeign.SpringQueryMap;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;


@FeignClient(name = "content-center", configuration = ContentCenterFeignConfiguration.class)
public interface ContentCenterFeignClient {

    @GetMapping(value = "/share/findById/{id}")
    ShareDto findShareById(@PathVariable(value = "id") Integer id);

    // 解决多参数请求问题：http://content-center/share/query?id=xx&title=xx&key=value...
    @GetMapping(value = "/share/query")
    ShareDto query(@SpringQueryMap ShareDto shareDto);

    // 解决多参数请求问题
    @PostMapping(value = "/share/insert")
    ShareDto insert(@RequestBody ShareDto shareDto);
}

7、feignclient/BaiduFeignClient.java

package com.geovis.usercenter.feignclient;


import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;


/*
* feign脱离ribbon使用
* */
@FeignClient(name = "baidu", url = "http://www.baidu.com")
public interface BaiduFeignClient {
    @GetMapping(value = "")
    String index();
}

8、TestController.java

package com.geovis.usercenter.controller.user;


import com.geovis.usercenter.domain.dto.ShareDto;
import com.geovis.usercenter.feignclient.BaiduFeignClient;
import com.geovis.usercenter.feignclient.ContentCenterFeignClient;
import lombok.RequiredArgsConstructor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import tk.mybatis.mapper.entity.Example;

import java.util.List;

// 解决idea自动注入的警告
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
@RestController
@RequestMapping("/test")
public class TestController {
    private final ContentCenterFeignClient contentCenterFeignClient;
    private final BaiduFeignClient baiduFeignClient;

    /*
     * 根据id查询share
     * */
    @GetMapping(value = "/findShare/{id}")
    public ShareDto findShare(@PathVariable Integer id){
        return this.contentCenterFeignClient.findShareById(id);
    }

    /*
     * 访问百度网页
     * */
    @GetMapping(value = "/index")
    public String baidu(){
        return this.baiduFeignClient.index();
    }
}

9、接口测试

1632543211(1).png

10、现有架构的问题

如果某个微服务停止，高并发的访问会导致线程池阻塞，发生雪崩效应。

3dc2aa79fdfd5716be53553ee932029.jpg

Feign声明式HTTP客户端

1、项目结构

2、pom.xml

3、UsercenterApplication.java主类

4、application.properties

5、configuration/ContentCenterFeignConfiguration.java

6、feignclient/ContentCenterFeignClient.java

7、feignclient/BaiduFeignClient.java

8、TestController.java

9、接口测试

10、现有架构的问题

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