[Java知识库]Spring Cloud Alibaba

Spring Cloud Alibaba

创建父工程

Spring Cloud Alibaba 的环境在父工程中创建，微服务的各个组件作为子工程，继承父工程的环境。

Spring Boot —》Spring Cloud —》Spring Cloud Alibaba

pom.xml 中添加。

<dependencyManagement>
    <dependencies>
        <!-- Spring Cloud Hoxton -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Hoxton.SR9</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
        <!-- Spring Cloud Alibaba -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-alibaba-dependencies</artifactId>
            <version>2.2.6.RELEASE</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

Nacos 服务注册

解压，启动服务。

sh startup.sh -m standalone

Nacos 搭建成功，接下来注册服务。

在父工程路径下创建子工程，让子工程继承父工程的环境依赖，pom.xml 中添加 nacos 发现组件。

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>

application.yml 中配置

spring:
  cloud:
    nacos:
      discovery:
        # 指定nacos server地址
        server-addr: localhost:8848
  application:
    name: my-nacos

Nacos 服务发现与调用

pom.xml 添加 discovery，完成服务发现。

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>

通过 discoveryClient 发现注册到 nacos 中的 provider 服务。

@RestController
public class ConsumerController {

    @Autowired
    private DiscoveryClient discoveryClient;

    @GetMapping("/instances")
    public List<ServiceInstance> instances(){
        List<ServiceInstance> provider = discoveryClient.getInstances("provider");
        return provider;
    }

}

@Configuration
public class ConsumerConfig {

    @Bean
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }

}

@RestController
public class ConsumerController {

    @Autowired
    private DiscoveryClient discoveryClient;
    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/index")
    public String index(){
        List<ServiceInstance> provider = discoveryClient.getInstances("provider");
        int index = ThreadLocalRandom.current().nextInt(provider.size());
        String url = provider.get(index).getUri()+"/index";
        return "consumer随机远程调用provier："+this.restTemplate.getForObject(url, String.class);
    }

}

Ribbon 负载均衡

@Configuration
public class ConsumerConfig {

    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }

}

@RestController
public class ConsumerController {

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/index")
    public String index(){
        return "consumer远程调用provier："+this.restTemplate.getForObject("http://provider/index", String.class);
    }

}

随机

server:
  port: 8180
provider:
  ribbon:
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule

Nacos 权重

@Slf4j
public class NacosWeightedRule extends AbstractLoadBalancerRule {

    @Autowired
    private NacosDiscoveryProperties nacosDiscoveryProperties;

    @Override
    public void initWithNiwsConfig(IClientConfig iClientConfig) {
        //读取配置文件
    }

    @Override
    public Server choose(Object o) {
        ILoadBalancer loadBalancer = this.getLoadBalancer();
        BaseLoadBalancer baseLoadBalancer = (BaseLoadBalancer) loadBalancer;
        //获取要请求的微服务名称
        String name = baseLoadBalancer.getName();
        //获取服务发现的相关API
        NamingService namingService = nacosDiscoveryProperties.namingServiceInstance();
        try {
            Instance instance = namingService.selectOneHealthyInstance(name);
            log.info("选择的实例是port={},instance={}",instance.getPort(),instance);
            return new NacosServer(instance);
        } catch (NacosException e) {
            e.printStackTrace();
            return null;
        }
    }
}

server:
  port: 8180
provider:
  ribbon:
    NFLoadBalancerRuleClassName: com.southwind.configuration.NacosWeightedRule

Sentinel 服务限流降级

雪崩效应

解决方案

1、设置线程超时

2、设置限流

3、熔断器 Sentinel、Hystrix

1、pom.xml 引入依赖

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>

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

2、application 配置

management:
  endpoints:
    web:
      exposure:
        include: '*'
spring:
  cloud:
    sentinel:
      transport:
        dashboard: localhost:8080

3、下载 Sentinel 控制台，解压，启动。

nohup java -Dserver.port=8081 -Dcsp.sentinel.dashboard.server=localhost:8081 -Dproject.name=sentinel-dashboard -jar sentinel-dashboard-1.8.1.jar >./sentinel.log 2>&1 &

流控规则

直接限流

关联限流

链路限流

1、pom.xml 添加依赖

<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-core</artifactId>
    <version>1.7.1</version>
</dependency>

<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-web-servlet</artifactId>
    <version>1.7.1</version>
</dependency>

2、application.yml

spring:
	cloud:
        sentinel:
          filter:
            enabled: false

3、写配置类

package com.southwind.configuration;

import com.alibaba.csp.sentinel.adapter.servlet.CommonFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class FilterConfiguration {

    @Bean
    public FilterRegistrationBean registrationBean(){
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(new CommonFilter());
        registrationBean.addUrlPatterns("/*");
        registrationBean.addInitParameter(CommonFilter.WEB_CONTEXT_UNIFY,"false");
        registrationBean.setName("sentinelFilter");
        return registrationBean;
    }
}

4、Service

@Service
public class HelloService {

    @SentinelResource("test")
    public void test(){
        System.out.println("test");
    }
}

5、Controller

@GetMapping("/test1")
public String test1(){
    this.helloService.test();
    return "test1";
}

@GetMapping("/test2")
public String test2(){
    this.helloService.test();
    return "test2";
}

流控效果

快速失败

直接抛出异常

Warm UP

给系统一个预热的时间，预热时间段内单机阈值较低，预热时间过后单机阈值增加，预热时间内当前的单机阈值是设置的阈值的三分之一，预热时间过后单机阈值恢复设置的值。

排队等待

当请求调用失败之后，不会立即抛出异常，等待下一次调用，时间范围是超时时间，在时间范围内如果能请求成功则不抛出异常，如果请求则抛出异常。

降级规则

熔断降级支持慢调用比例、异常比例、异常数三种熔断策略。

先明确下面两个概念：

慢调用 ： 指耗时大于阈值RT的请求称为慢调用，阈值RT由用户设置

最小请求数 ： 允许通过的最小请求数量，在最小请求数量内不发生熔断，由用户设置

熔断有三种状态，分别为OPEN、HALF_OPEN、CLOSED。

1.慢调用比例

执行逻辑

熔断（OPEN）：请求数大于最小请求数并且慢调用的比率大于比例阈值则发生熔断，熔断时长为用户自定义设置。

探测（HALFOPEN）：当熔断过了定义的熔断时长，状态由熔断（OPEN）变为探测（HALFOPEN）。

• 如果接下来的一个请求小于最大RT，说明慢调用已经恢复，结束熔断，状态由探测（HALF_OPEN）变更为关闭（CLOSED）
• 如果接下来的一个请求大于最大RT，说明慢调用未恢复，继续熔断，熔断时长保持一致

2.异常比例

通过计算异常比例与设置阈值对比的一种策略。

执行逻辑

熔断（OPEN）：当请求数大于最小请求并且异常比例大于设置的阈值时触发熔断，熔断时长由用户设置。

探测（HALFOPEN）：当超过熔断时长时，由熔断（OPEN）转为探测（HALFOPEN）

• 如果接下来的一个请求未发生错误，说明应用恢复，结束熔断，状态由探测（HALF_OPEN）变更为关闭（CLOSED）

• 如果接下来的一个请求继续发生错误，说明应用未恢复，继续熔断，熔断时长保持一致

3.异常数

通过计算发生异常的请求数与设置阈值对比的一种策略。

执行逻辑

熔断（OPEN）：当请求数大于最小请求并且异常数量大于设置的阈值时触发熔断，熔断时长由用户设置。探测（HALFOPEN）：当超过熔断时长时，由熔断（OPEN）转为探测（HALFOPEN）

• 如果接下来的一个请求未发生错误，说明应用恢复，结束熔断，状态由探测（HALF_OPEN）变更为关闭（CLOSED）
• 如果接下来的一个请求继续发生错误，说明应用未恢复，继续熔断，熔断时长保持一致

热点规则

热点规则是流控规则的更细粒度操作，可以具体到对某个热点参数的限流，设置限流之后，如果带着限流参数的请求量超过阈值，则进行限流，时间为统计窗口时长。

必须要添加 @SentinelResource，即对资源进行流控。

@GetMapping("/hot")
@SentinelResource("hot")
public String hot(
        @RequestParam(value = "num1",required = false) Integer num1,
        @RequestParam(value = "num2",required = false) Integer num2){
    return num1+"-"+num2;
}

授权规则

给指定的资源设置流控应用（追加参数），可以对流控应用进行访问权限的设置，具体就是添加白名单和黑名单。

如何给请求指定流控应用，通过实现 RequestOriginParser 接口来完成，代码如下所示。

package com.southwind.configuration;

import com.alibaba.csp.sentinel.adapter.servlet.callback.RequestOriginParser;
import org.springframework.util.StringUtils;

import javax.servlet.http.HttpServletRequest;

public class RequestOriginParserDefinition implements RequestOriginParser {
    @Override
    public String parseOrigin(HttpServletRequest httpServletRequest) {
        String name = httpServletRequest.getParameter("name");
        if(StringUtils.isEmpty(name)){
            throw new RuntimeException("name is null");
        }
        return name;
    }
}

要让 RequestOriginParserDefinition 生效，需要在配置类中进行配置。

package com.southwind.configuration;

import com.alibaba.csp.sentinel.adapter.servlet.callback.WebCallbackManager;
import org.springframework.context.annotation.Configuration;

import javax.annotation.PostConstruct;

@Configuration
public class SentinelConfiguration {

    @PostConstruct
    public void init(){
        WebCallbackManager.setRequestOriginParser(new RequestOriginParserDefinition());
    }
}

自定义规则异常返回

创建异常处理类

package com.southwind.handler;

import com.alibaba.csp.sentinel.adapter.servlet.callback.UrlBlockHandler;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeException;
import com.alibaba.csp.sentinel.slots.block.flow.FlowException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class ExceptionHandler implements UrlBlockHandler {
    @Override
    public void blocked(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, BlockException e) throws IOException {
        httpServletResponse.setContentType("text/html;charset=utf-8");
        String msg = null;
        if(e instanceof FlowException){
            msg = "限流";
        }else if(e instanceof DegradeException){
            msg = "降级";
        }
        httpServletResponse.getWriter().write(msg);
    }
}

进行配置。

@Configuration
public class SentinelConfiguration {

    @PostConstruct
    public void init(){
        WebCallbackManager.setUrlBlockHandler(new ExceptionHandler());
    }
}

整合 RocketMQ

安装 RocketMQ

1、传入 Linux 服务器

2、解压缩

unzip rocketmq-all-4.7.1-bin-release.zip

3、启动 NameServer

nohup sh mqnamesrv &

4、检查是否启动成功

netstat -an | grep 9876

5、启动 Broker

启动之前需要编辑配置文件，修改 JVM 内存设置，默认给的内存 4 GB，超过我们的 JVM 了。

cd bin
vim runserver.sh

vim runbroker.sh

启动 Broker

nohup sh mqbroker -n localhost:9876 &

可以查看日志

tail -f ~/logs/rocketmqlogs/broker.log

启动成功

6、测试 RocketMQ

消息发送

cd bin
export NAMESRV_ADDR=localhost:9876
sh tools.sh org.apache.rocketmq.example.quickstart.Producer

消息接收

cd bin
export NAMESRV_ADDR=localhost:9876
sh tools.sh org.apache.rocketmq.example.quickstart.Consumer

7、关闭 RocketMQ

cd bin
sh mqshutdown broker
sh mqshutdown namesrv

安装 RocketMQ 控制台

1、解压缩，修改配置，打包

mvn clean package -Dmaven.test.skip=true

2、进入 target 启动 jar

java -jar rocketmq-console-ng-1.0.0.jar 

打开浏览器访问 localhost:9877，如果报错

这是因为我们的 RocketMQ 安装在 Linux 中，控制台在 windows，Linux 需要开放端口才能访问，开放 10909 和 9876 端口

firewall-cmd --zone=public --add-port=10909/tcp --permanent
firewall-cmd --zone=public --add-port=10911/tcp --permanent
firewall-cmd --zone=public --add-port=9876/tcp --permanent
systemctl restart firewalld.service
firewall-cmd --reload

重新启动控制台项目

Java 实现消息发送

1、pom.xml 中引入依赖

<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-spring-boot-starter</artifactId>
    <version>2.1.0</version>
</dependency>

2、生产消息

package com.southwind;

import org.apache.rocketmq.client.producer.DefaultMQProducer;
import org.apache.rocketmq.client.producer.SendResult;
import org.apache.rocketmq.common.message.Message;

public class Test {
    public static void main(String[] args) throws Exception {
        //创建消息生产者
        DefaultMQProducer producer = new DefaultMQProducer("my-producer-group");
        //设置NameServer
        producer.setNamesrvAddr("192.168.248.129:9876");
        //启动生产者
        producer.start();
        //构建消息对象
        Message message = new Message("myTopic","myTag",("Test MQ").getBytes());
        //发送消息
        SendResult result = producer.send(message, 1000);
        System.out.println(result);
        //关闭生产者
        producer.shutdown();
    }
}

3、直接运行，如果报错 sendDefaultImpl call timeout，加大超时时间就搞定了

producer.send(message, 100000);

打开 RocketMQ 控制台，可查看消息。

Java 实现消息消费

package com.southwind.service;

import lombok.extern.slf4j.Slf4j;
import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.client.exception.MQClientException;
import org.apache.rocketmq.common.message.MessageExt;

import java.util.List;

@Slf4j
public class ConsumerTest {
    public static void main(String[] args) throws MQClientException {
        //创建消息消费者
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("my-consumer-group");
        //设置NameServer
        consumer.setNamesrvAddr("192.168.248.129:9876");
        //指定订阅的主题和标签
        consumer.subscribe("myTopic","*");
        //回调函数
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> list, ConsumeConcurrentlyContext consumeConcurrentlyContext) {
                log.info("Message=>{}",list);
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        //启动消费者
        consumer.start();
    }
}

Spring Boot 整合 RocketMQ

provider

1、pom.xml

<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-spring-boot-starter</artifactId>
    <version>2.1.0</version>
</dependency>
<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-client</artifactId>
    <version>4.7.0</version>
</dependency>

2、application.yml

rocketmq:
  name-server: 192.168.248.129:9876
  producer:
    group: myprovider

3、Order

package com.southwind.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.Date;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Order {
    private Integer id;
    private String buyerName;
    private String buyerTel;
    private String address;
    private Date createDate;
}

4、Controller

@Autowired
private RocketMQTemplate rocketMQTemplate;

@GetMapping("/create")
public Order create(){
    Order order = new Order(
        1,
        "张三",
        "123123",
        "软件园",
        new Date()
    );
    this.rocketMQTemplate.convertAndSend("myTopic",order);
    return order;
}

consumer

1、pom.xml

<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-spring-boot-starter</artifactId>
    <version>2.1.0</version>
</dependency>
<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-client</artifactId>
    <version>4.7.0</version>
</dependency>

2、application.yml

rocketmq:
  name-server: 192.168.248.129:9876

3、Service

@Slf4j
@Service
@RocketMQMessageListener(consumerGroup = "myConsumer",topic = "myTopic")
public class SmsService implements RocketMQListener<Order> {
    @Override
    public void onMessage(Order order) {
        log.info("新订单{},发短信",order);
    }
}

服务网关

Spring Cloud Gateway 是基于 Netty，跟 Servlet 不兼容，所以你的工程中不能出现 Servlet 的组件 。

1、pom.xml

注意，一定不能出现 spring web 的依赖，因为 Gateway 与 Servlet 不兼容。

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>

2、application.yml

server:
  port: 8010
spring:
  application:
    name: gateway
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true
      routes: 
        - id: provider_route   
          uri: http://localhost:8081 
          predicates: 
            - Path=/provider/** 
          filters:
            - StripPrefix=1

上面这种做法其实没有用到 nacos ，现在我们让 gateway 直接去 nacos 中发现服务，配置更加简单了。

1、pom.xml 引入 nacos

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>

2、application.yml

server:
  port: 8020
spring:
  application:
    name: gateway
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true
    nacos:
      discovery:
        server-addr: 192.168.204.134:8848

Gateway 负载均衡

基于nacos负载均衡

1、pom.xml

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-gateway</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-loadbalancer</artifactId>
    </dependency>
    <dependency>
        <groupId>com.alibaba.cloud</groupId>
        <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
    </dependency>
</dependencies>

2、配置类

@Slf4j
public class NacosWeightedRule extends AbstractLoadBalancerRule {

    @Autowired
    private NacosDiscoveryProperties nacosDiscoveryProperties;

    @Override
    public void initWithNiwsConfig(IClientConfig iClientConfig) {
        //读取配置文件
    }

    @Override
    public Server choose(Object o) {
        ILoadBalancer loadBalancer = this.getLoadBalancer();
        BaseLoadBalancer baseLoadBalancer = (BaseLoadBalancer) loadBalancer;
        //获取要请求的微服务名称
        String name = baseLoadBalancer.getName();
        //获取服务发现的相关API
        NamingService namingService = nacosDiscoveryProperties.namingServiceInstance();
        try {
            Instance instance = namingService.selectOneHealthyInstance(name);
            log.info("选择的实例是port={},instance={}",instance.getPort(),instance);
            return new NacosServer(instance);
        } catch (NacosException e) {
            e.printStackTrace();
            return null;
        }
    }
}

3、application.yml

server:
  port: 8020
spring:
  application:
    name: gateway
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true
    nacos:
      discovery:
        server-addr: 192.168.204.134:8848
provider:
  ribbon:
    NFLoadBalancerRuleClassName: com.yt.config.NacosWeightedRule

Gateway 限流

基于路由限流

1、pom.xml

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>

<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
</dependency>

2、配置类

package com.yt.config;

import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayFlowRule;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayRuleManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.SentinelGatewayFilter;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.BlockRequestHandler;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.GatewayCallbackManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.exception.SentinelGatewayBlockExceptionHandler;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.codec.ServerCodecConfigurer;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.ServerResponse;
import org.springframework.web.reactive.result.view.ViewResolver;

import javax.annotation.PostConstruct;
import java.util.*;

/**
 * ClassName:GatewayConfiguration
 * Package:com.yt.config
 * Description:
 *
 * @date:2022/1/19 14:56
 * @author:yt
 */

@Configuration
public class GatewayConfiguration {
    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;


    public GatewayConfiguration(ObjectProvider<List<ViewResolver>> viewResolversProvider,
                                ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
        this.serverCodecConfigurer = serverCodecConfigurer;
    }

    /**
     * 配置限流的异常处理
     *
     * @return
     */
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }

    /**
     * 配置初始化的限流参数
     */
    @PostConstruct
    public void initGatewayRules() {
        Set<GatewayFlowRule> rules = new HashSet<>();
        rules.add(
                new GatewayFlowRule("provider_route")
                        .setCount(1)
                        .setIntervalSec(1)
        );
        GatewayRuleManager.loadRules(rules);
    }

    /**
     * 初始化限流过滤器
     *
     * @return
     */
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }


     /**
     * 自定义限流异常页面
     */
    @PostConstruct
    public void initBlockHandlers() {
        BlockRequestHandler blockRequestHandler = (serverWebExchange, throwable) -> {
            Map<String, Object> map = new HashMap<>();
            map.put("code", 0);
            map.put("msg", "被限流了");
            return ServerResponse.status(HttpStatus.OK)
                    .contentType(MediaType.APPLICATION_JSON)
                    .body(BodyInserters.fromObject(map));
        };
        GatewayCallbackManager.setBlockHandler(blockRequestHandler);
    }
}

3、application.yml

server:
  port: 8010
spring:
  application:
    name: gateway
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true
      routes:
        - id: provider_route
          uri: http://localhost:8081
          predicates:
            - Path=/provider/**
          filters:
            - StripPrefix=1

基于 API 分组限流

1、修改配置类，添加基于 API 分组限流的方法，修改初始化的限流参数

package com.yt.config;

import com.alibaba.csp.sentinel.adapter.gateway.common.SentinelGatewayConstants;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiDefinition;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiPathPredicateItem;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiPredicateItem;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.GatewayApiDefinitionManager;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayFlowRule;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayRuleManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.SentinelGatewayFilter;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.BlockRequestHandler;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.GatewayCallbackManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.exception.SentinelGatewayBlockExceptionHandler;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.codec.ServerCodecConfigurer;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.ServerResponse;
import org.springframework.web.reactive.result.view.ViewResolver;

import javax.annotation.PostConstruct;
import java.util.*;

/**
 * ClassName:GatewayConfiguration
 * Package:com.yt.config
 * Description:
 *
 * @date:2022/1/19 14:56
 * @author:yt
 */

@Configuration
public class GatewayConfiguration {
    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;


    public GatewayConfiguration(ObjectProvider<List<ViewResolver>> viewResolversProvider,
                                ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
        this.serverCodecConfigurer = serverCodecConfigurer;
    }

    /**
     * 配置限流的异常处理
     *
     * @return
     */
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }

    /**
     * 配置初始化的限流参数
     */
    @PostConstruct
    public void initGatewayRules() {
        Set<GatewayFlowRule> rules = new HashSet<>();
        rules.add(new GatewayFlowRule("provider_api1").setCount(1).setIntervalSec(1));
        rules.add(new GatewayFlowRule("provider_api2").setCount(1).setIntervalSec(1));
        GatewayRuleManager.loadRules(rules);
    }

    /**
     * 初始化限流过滤器
     *
     * @return
     */
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }


    /**
     * 自定义限流异常页面
     */
    @PostConstruct
    public void initBlockHandlers() {
        BlockRequestHandler blockRequestHandler = (serverWebExchange, throwable) -> {
            Map<String, Object> map = new HashMap<>();
            map.put("code", 0);
            map.put("msg", "被限流了");
            return ServerResponse.status(HttpStatus.OK)
                    .contentType(MediaType.APPLICATION_JSON)
                    .body(BodyInserters.fromObject(map));
        };
        GatewayCallbackManager.setBlockHandler(blockRequestHandler);
    }

    /**
     * 自定义API分组
     */
    @PostConstruct
    private void initCustomizedApis(){
        Set<ApiDefinition> definitions = new HashSet<>();
        ApiDefinition api1 = new ApiDefinition("provider_api1")
                .setPredicateItems(new HashSet<ApiPredicateItem>(){{
                    add(new ApiPathPredicateItem().setPattern("/provider/api1/**")
                            .setMatchStrategy(SentinelGatewayConstants.URL_MATCH_STRATEGY_PREFIX));
                }});
        ApiDefinition api2 = new ApiDefinition("provider_api2")
                .setPredicateItems(new HashSet<ApiPredicateItem>(){{
                    add(new ApiPathPredicateItem().setPattern("/provider/api2/demo1"));
                }});
        definitions.add(api1);
        definitions.add(api2);
        GatewayApiDefinitionManager.loadApiDefinitions(definitions);
    }
}

2、Controller 添加方法

@GetMapping("/api1/demo1")
public String demo1(){
    return "demo";
}

@GetMapping("/api1/demo2")
public String demo2(){
    return "demo";
}

@GetMapping("/api2/demo1")
public String demo3(){
    return "demo";
}

@GetMapping("/api2/demo2")
public String demo4(){
    return "demo";
}

也可以基于 Nacos 服务发现组件进行限流

server:
  port: 8010
spring:
  application:
    name: gateway
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true

API 分组代码修改，改为 discovery 中的服务名。

ApiDefinition api2 = new ApiDefinition("provider_api2")
        .setPredicateItems(new HashSet<ApiPredicateItem>(){{
            add(new ApiPathPredicateItem().setPattern("/p1/api2/demo1"));
        }});

分布式事务

模拟分布式事务异常

1、创建两个工程 order、pay，pom.xml

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

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

2、建两个数据库 order、pay，两个微服务分别访问。

3、分别写两个服务的 application.yml

server:
  port: 8010
spring:
  application:
    name: order
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/order

server:
  port: 8020
spring:
  application:
    name: pay
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/pay

4、分别写两个 Service

package com.southwind.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Service;

@Service
public class OrderService {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    public void save(){
        this.jdbcTemplate.update("insert into orders(username) values ('张三')");
    }
}

package com.southwind.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Service;

@Service
public class PayService {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    public void save(){
        this.jdbcTemplate.update("insert into pay(username) values ('张三')");
    }
}

5、控制器 Order 通过 RestTemplate 调用 Pay 的服务

package com.southwind.controller;

import com.southwind.service.OrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class OrderController {

    @Autowired
    private OrderService orderService;
    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/save")
    public String save(){
        //订单
        this.orderService.save();
        int i = 10/0;
        //支付
        this.restTemplate.getForObject("http://localhost:8020/save",String.class);
        return "success";
    }
}

package com.southwind.controller;

import com.southwind.service.PayService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class PayController {
    @Autowired
    private PayService payService;

    @GetMapping("/save")
    public String save(){
        this.payService.save();
        return "success";
    }
}

6、启动类

package com.southwind;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
public class OrderApplication {

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

    @Bean
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
}

package com.southwind;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class PayApplication {

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

}

分布式异常模拟结束，Order 存储完成之后，出现异常，会导致 Pay 无法存储，但是 Order 数据库不会进行回滚。

Seata 解决

安装参考：https://www.cnblogs.com/zjdxr-up/p/15221388.html

https://blog.csdn.net/calonmo/article/details/106630754

安装Seata，指定nacos作为配置中心和注册中心

1、下载地址：https://seata.io/zh-cn/blog/download.html，版本为1.4.0，解压后修改conf/registry.conf文件

registry {
  # file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
  type = "nacos"
  loadBalance = "RandomLoadBalance"
  loadBalanceVirtualNodes = 10

  nacos {
    application = "seata-server"
    serverAddr = "127.0.0.1:8848"
    group = "SEATA_GROUP"
    namespace = ""
    cluster = "default"
    username = ""
    password = ""
  }
  
}

config {
  # file、nacos 、apollo、zk、consul、etcd3
  type = "nacos"

  nacos {
    serverAddr = "127.0.0.1:8848"
    namespace = ""
    group = "SEATA_GROUP"
    username = "nacos"
    password = "nacos"
  }

}

由于使用nacos作为注册中心，所以conf目录下的file.conf无需理会。然后就可以直接启动seata：sh bin/seata-server.sh，可以在nacos里看到一个名为seata-server的服务了。

2、由于seata使用mysql作为db高可用数据库，故需要在mysql创建一个seata库，并导入数据库脚本，脚本地址：https://github.com/seata/seata/tree/develop/script/server/db

3、导入配置到nacos的配置中心，到https://github.com/seata/seata/tree/develop/script/config-center这里下载跟目录的confix.txt配置文件以及到nacos目录下载nacos-config.sh脚本，修改config.txt文件内容：

service.vgroupMapping.my_test_tx_group=default
store.mode=db
store.db.datasource=druid
store.db.dbType=mysql
store.db.driverClassName=com.mysql.jdbc.Driver
store.db.url=jdbc:mysql://127.0.0.1:3306/seata?useUnicode=true&rewriteBatchedStatements=true
## 数据库用户密码自行更改
store.db.user=root 
store.db.password=root
store.db.minConn=5
store.db.maxConn=30
store.db.globalTable=global_table
store.db.branchTable=branch_table
store.db.queryLimit=100
store.db.lockTable=lock_table
store.db.maxWait=5000

上面关于vgroupMapping.my_test_tx_group是和在项目里配置的一致。

seata:
  # seata 服务分组，要与服务端config.txt中service.vgroup_mapping的后缀对应
  tx-service-group: my_test_tx_group

4、执行nacos-config.sh把config.txt文件导入到nacos配置中心，执行出现找不到config.txt的话修改一下nacos-config.sh里面关于config.txt的路径。

sh nacos-config.sh -h localhost -p 8848 -g SEATA_GROUP -t 5a3c7d6c-f497-4d68-a71a-2e5e3340b3ca -u username -w password

参数说明：

-h: host，默认值 localhost

-p: port，默认值 8848

-g: 配置分组，默认值为 ‘SEATA_GROUP’

-t: 租户信息，对应 Nacos 的命名空间ID字段, 默认值为空。

也可以直接使用以下命令进行同步

sh nacos-config.sh -h localhost -p 8848 -g SEATA_GROUP

5、启动Seata Server命令

sh bin/seata-server.sh

Seata整合到Spring Cloud微服务

1、两个工程的 pom.xml 添加对应依赖。

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-seata</artifactId>
    <exclusions>
        <exclusion>
            <groupId>io.seata</groupId>
            <artifactId>seata-spring-boot-starter</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>io.seata</groupId>
    <artifactId>seata-spring-boot-starter</artifactId>
    <version>1.4.0</version>
</dependency>


<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
</dependency>


<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

2、给 JDBCTemplate 添加代理数据源

package com.southwind;

import io.seata.rm.datasource.DataSourceProxy;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.client.RestTemplate;

import javax.sql.DataSource;

@SpringBootApplication
public class OrderApplication {

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

    @Bean
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }

    @Bean
    public JdbcTemplate jdbcTemplate(DataSource dataSource){
        return new JdbcTemplate(new DataSourceProxy(dataSource));
    }
}

package com.southwind;

import io.seata.rm.datasource.DataSourceProxy;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.core.JdbcTemplate;

import javax.sql.DataSource;

@SpringBootApplication
public class PayApplication {

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

    @Bean
    public JdbcTemplate jdbcTemplate(DataSource dataSource){
        return new JdbcTemplate(new DataSourceProxy(dataSource));
    }

}

3、直接在两个数据库运行脚本。

CREATE TABLE `undo_log` ( 
 `id` bigint(20) NOT NULL AUTO_INCREMENT, 
 `branch_id` bigint(20) NOT NULL, 
 `xid` varchar(100) NOT NULL, 
 `context` varchar(128) NOT NULL, 
 `rollback_info` longblob NOT NULL, 
 `log_status` int(11) NOT NULL, 
 `log_created` datetime NOT NULL, 
 `log_modified` datetime NOT NULL, 
 PRIMARY KEY (`id`), 
 UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`) 
 ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

4、给两个工程application.yml添加读取 Nacos 配置。

seata:
  enabled: true
  application-id: ${spring.application.name}
  # seata 服务分组，要与服务端nacos‐config.txt中service.vgroup_mapping的后缀对应
  tx-service-group: order
  config:
    # 指定nacos作为配置中心
    type: nacos
    nacos:
      namespace:
      serverAddr: 192.168.204.134:8848
      group: SEATA_GROUP

  registry:
    # 指定nacos作为注册中心
    type: nacos
    nacos:
      application: seata-server
      server-addr: 192.168.204.134:8848
      namespace:

seata:
  enabled: true
  application-id: ${spring.application.name}
  # seata 服务分组，要与服务端nacos‐config.txt中service.vgroup_mapping的后缀对应
  tx-service-group: pay
  config:
    # 指定nacos作为配置中心
    type: nacos
    nacos:
      namespace:
      serverAddr: 192.168.204.134:8848
      group: SEATA_GROUP

  registry:
    # 指定nacos作为注册中心
    type: nacos
    nacos:
      application: seata-server
      server-addr: 192.168.204.134:8848
      namespace:

注意如果nacos不在本地运行，需要添加nacos发现

spring:
  cloud:
    nacos:
      discovery:
        server-addr: 192.168.204.134:8848

5、在 Order 调用 Pay 处添加注解 @GlobalTransactional

package com.southwind.controller;

import com.southwind.service.OrderService;
import io.seata.spring.annotation.GlobalTransactional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class OrderController {

    @Autowired
    private OrderService orderService;
    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/save")
    @GlobalTransactional
    public String save(){
        //订单
        this.orderService.save();
        int i = 10/0;
        //支付
        this.restTemplate.getForObject("http://localhost:8020/save",String.class);
        return "success";
    }
}

注意如果nacos不在本地运行，需要添加nacos发现

spring:
  cloud:
    nacos:
      discovery:
        server-addr: 192.168.204.134:8848

5、在 Order 调用 Pay 处添加注解 @GlobalTransactional

package com.southwind.controller;

import com.southwind.service.OrderService;
import io.seata.spring.annotation.GlobalTransactional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class OrderController {

    @Autowired
    private OrderService orderService;
    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/save")
    @GlobalTransactional
    public String save(){
        //订单
        this.orderService.save();
        int i = 10/0;
        //支付
        this.restTemplate.getForObject("http://localhost:8020/save",String.class);
        return "success";
    }
}