Articles posted by: Alan

Spring cloud配置Ribbon用于负载君和，如果要在细节上配置更多，那么需要阅读一下官方文档。

* RoundRobinRule:轮询
* RandomRule:随机
* AvailabilityFilteringRule: 会先过滤掉由于多次访问故障而处于断路器跳闸状态的服务,以及并发的连接数量
*      超过阈值的服务,然后对剩余的服务列表按照轮询策略进行访问;
* WeightedResponseTimeRule: 根据平均响应时间计算所有服务的权重,响应时间越快,服务权重越大,被选中的机率越高;
*      刚启动时,如果统计信息不足,则使用RoundRobinRule策略,等统计信息足够时,会切换到WeightedResponseTimeRule
* RetryRule: 先按照RoundRobinRule的策略获取服务,如果获取服务失败,则在指定时间内会进行重试,获取可用的服务;
* BestAvailableRule: 会先过滤掉由于多次访问故障而处于断路器跳闸状态的服务,然后选择一个并发量最小的服务;
* ZoneAvoidanceRule: 默认规则,复合判断server所在区域的性能和server的可用性选择服务器;

首先maven文件：

<?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>2.2.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.test</groupId>
    <artifactId>router</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>router</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Hoxton.M3</spring-cloud.version>
    </properties>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
        </repository>
    </repositories>

</project>

配置文件：

server:
  address: 127.0.0.1
  port: 7001
  undertow:
    io-threads: 19 # 设置IO线程数, 它主要执行非阻塞的任务,它们会负责多个连接, 默认设置每个CPU核心一个线程
    worker-threads: 24 # 阻塞任务线程池, 当执行类似servlet请求阻塞操作, undertow会从这个线程池中取得线程,它的值设置取决于系统的负载
    buffer-size: 1024 # 以下的配置会影响buffer,这些buffer会用于服务器连接的IO操作,有点类似netty的池化内存管理
    direct-buffers: true # 是否分配的直接内存
    always-set-keep-alive: true #socket-binding="http"，保持长连接

spring:
  application:
    name: router-server
  profiles:
    active: test
  cloud:
    loadbalancer:
      retry:
        enabled: true #重试机制开启为true，关闭为false

eureka:
  instance:
    appname: router-server
    virtual-host-name: router-server
    secure-virtual-host-name: router-server
    instance-id: ${server.address}:router-server-peer:${server.port}
    hostname: localhost
#    non-secure-port: 6001 #非安全通信端口
#    non-secure-port-enabled: true #是否启用非安全端口接受请求
#    secure-port: 6444 #安全通信端口
#    secure-port-enabled: true #是否启用安全端口接受请求
    prefer-ip-address: false #是否优先使用IP地址作为主机名的标识，默认false
    lease-renewal-interval-in-seconds: 30 #eureka节点定时续约时间，默认30
    lease-expiration-duration-in-seconds: 90 #eureka节点剔除时间，默认90
  client:
    register-with-eureka: true #将自己注册到eureka注册中心，单节点关闭
    fetch-registry: true #从注册中心获取注册信息，单节点关闭
    registry-fetch-interval-seconds: 30 #从注册中心获取注册信息的时间间隔
    eureka-server-connect-timeout-seconds: 15
    eureka-server-read-timeout-seconds: 10
    service-url:
      defaultZone: http://${eureka.instance.hostname}:7000/eureka/ #注册到另外两个节点，实现集群

ribbon:
  eureka:
    enabled: true

注解开启服务：

@EnableEurekaClient
@SpringBootApplication
public class RouterApplication {

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

}

写一个RestTemplate服务层，用于公共接口转发：

package com.test.router.system.service;

import com.test.router.system.core.BaseService;
import com.test.router.system.core.ResultResp;
import com.test.router.system.service.resources.IAPIDispatcherService;
import org.springframework.http.*;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

import javax.annotation.Resource;
import java.util.Map;

@Service
public class APIDispatcherServiceImpl extends BaseService implements IAPIDispatcherService {

    @Resource
    private RestTemplate restTemplate;


    @Override
    public ResultResp<Map<String, Object>> getForObject(String name, Object... uriVariables) {
        return restTemplate.getForObject("http://api-server/" + name, ResultResp.class);
    }

    @Override
    public ResultResp<Map<String, Object>> postForObject(String name, Map<String, Object> body) {
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        HttpEntity<Map<String, Object>> data = new HttpEntity<>(body,headers);

        ResponseEntity<ResultResp> resp = restTemplate.postForEntity("http://api-server/" + name , data, ResultResp.class);
        return resp.getBody();
    }

    @Override
    public ResultResp<Map<String, Object>> putForObject(String name, Integer id, Map<String, Object> body) {
        HttpEntity<Map<String, Object>> data = new HttpEntity<>(body);
        ResponseEntity<ResultResp> resp = restTemplate.exchange("http://api-server/" + name + "/{1}", HttpMethod.PUT, data, ResultResp.class, id);
        return resp.getBody();
    }

    @Override
    public ResultResp<Map<String, Object>> deleteForObject(String name, Integer id) {
        ResponseEntity<ResultResp> resp = restTemplate.exchange("http://api-server/" + name + "/{1}", HttpMethod.PUT, null, ResultResp.class, id);
        return resp.getBody();
    }
}

最后需要一个控制器，用于转发使用：

package com.test.router.app.v1;

import com.test.router.app.base.BaseV1Controller;
import com.test.router.constant.Constant;
import com.test.router.system.base.IDefaultRestController;
import com.test.router.system.core.ResultResp;
import com.test.router.system.model.http.Request;
import com.test.router.system.service.resources.IAPIDispatcherService;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.Map;

@RestController
public class TestController extends BaseV1Controller implements IDefaultRestController {


    @Resource
    private IAPIDispatcherService dispatcherService;

    /**
     * http://127.0.0.1:7001/v1/router?name=v2/test&namespace=api&user=avc
     * @param request
     * @param response
     * @return
     */
    @RequestMapping(value = "/router", method = RequestMethod.GET)
    @Override
    public ResultResp<Map<String, Object>> doGet(HttpServletRequest request, HttpServletResponse response) {
        String namespace = request.getParameter("namespace");
        String name = request.getParameter("name");

        if (Constant.NAMESPACE_API.equals(namespace)) {
            Map<String, String> args = this.initUriVariables(name, request);
            StringBuffer sb = new StringBuffer();
            if (name.lastIndexOf("?") == -1) {
                name += "?";
            }
            sb.append(name);
            args.forEach((k, v) -> {
                sb.append(k).append("=").append(v).append("&");
            });
            return dispatcherService.getForObject(sb.toString(), null);
        }

        return new ResultResp<>();
    }

    /**
     * http://127.0.0.1:7001/v1/router?user=avc
     *
     *
     * {
     *     "header":{
     *         "namespace":"api",
     *         "name":"v2/test"
     *     },
     *     "payload":{
     *         "username":"张三",
     *         "age":15
     *     }
     * }
     * @param body
     * @param request
     * @param response
     * @return
     */
    @RequestMapping(value = "/router", method = RequestMethod.POST)
    @Override
    public ResultResp<Map<String, Object>> doPost(@RequestBody Request<Map<String, Object>> body, HttpServletRequest request, HttpServletResponse response) {
        String namespace = body.getHeader().getNamespace();
        String name = body.getHeader().getName();

        if (Constant.NAMESPACE_API.equals(namespace)) {
            Map<String, String> args = this.initUriVariables(name, request);
            StringBuffer sb = new StringBuffer();
            if (name.lastIndexOf("?") == -1) {
                name += "?";
            }
            sb.append(name);
            args.forEach((k, v) -> {
                sb.append(k).append("=").append(v).append("&");
            });
            return dispatcherService.postForObject(sb.toString(), body.getPayload());
        }

        return new ResultResp<>();
    }

    @Override
    public ResultResp<Map<String, Object>> doPut(@PathVariable Integer id, @RequestBody Request<Map<String, Object>> obj, HttpServletRequest request, HttpServletResponse response) {
        return null;
    }

    @Override
    public ResultResp<Map<String, Object>> doDelete(@PathVariable Integer id, HttpServletRequest request, HttpServletResponse response) {
        return null;
    }
}

这样子基本上完成，主要使用浏览器打开http://127.0.0.1:7001/v1/router?name=v2/test&namespace=api&user=avc，就会根据name对应的值去获取api-service的对应的接口。

更多请参阅:

https://cloud.spring.io/spring-cloud-static/spring-cloud-netflix/2.2.0.RC1/reference/html/#spring-cloud-ribbon