SpringCloud学习笔记（1）- Spring Cloud Alibaba

落日映苍穹つ 2022-09-10 13:20 243阅读 0赞

### 文章目录 ###

*  SpringCloud学习笔记（1）- Spring Cloud Alibaba
 *  服务治理
 *   *  Nacos 服务注册
     *  Nacos 服务发现与调用
     *  Ribbon 负载均衡
     *  Sentinel 服务限流降级
     *   *  流控规则
         *  流控效果
         *  降级规则
         *  热点规则
         *  授权规则
         *  自定义规则异常返回
     *  整合 RocketMQ
     *   *  安装 RocketMQ
         *  安装 RocketMQ 控制台
         *  Java 实现消息发送
         *  Java 实现消息消费
     *  Spring Boot 整合 RocketMQ
     *  服务网关
     *   *  Gateway 限流
     *  分布式事务
     *   *  模拟分布式事务异常
         *  Seata 解决（事务回滚）

# SpringCloud学习笔记（1）- 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>
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.SR3</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2.2.1.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

# 服务治理 #

服务注册 + 服务发现

## Nacos 服务注册 ##

解压，启动服务。

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);
        }
    
    }

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16]

## 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 （随机的算法）

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

> Nacos 权重 （基于权重的算法）

@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  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 1]  
解决方案

1、设置线程超时

2、设置限流

3、熔断器 Sentinel、Hystrix （类比保险丝）

*  降级
 *  限流
 *  熔断

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 2]  
1、provider模块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。

### 流控规则 ###

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 3]

> 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（让能关联到Service）

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");  //让所有链路开放出来才能限制
            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 ###

> RT

单个请求的响应时间超过阈值，则进入准降级状态，接下来 1 S 内连续 5 个请求响应时间均超过阈值，就进行降级，持续时间为时间窗口的值。

> 异常比例

每秒异常数量占通过量的比例大于阈值，就进行降级处理，持续时间为时间窗口的值。

> 异常数

1 分钟内的异常数超过阈值就进行降级处理，时间窗口的值要大于 60S，否则刚结束熔断又进入下一次熔断了。

### 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 ./bin/mqnamesrv &

4、检查是否启动成功

netstat -an | grep 9876

![在这里插入图片描述][7642d896715d40f9a0ff65fd7a5d72c7.png]  
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

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 4]

vim runbroker.sh

![在这里插入图片描述][55053c34de9746aabe84d6925988ef4b.png]  
启动 Broker

nohup ./mqbroker -n localhost:9876 &

可以查看日志

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

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 5]  
启动成功

6、测试 RocketMQ

消息发送

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

消息接收

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

7、关闭 RocketMQ

cd bin
    ./mqshutdown broker
    ./mqshutdown namesrv

### 安装 RocketMQ 控制台 ###

1、解压缩，修改配置，打包

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 6]

mvn clean package -Dmaven.test.skip=true

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 7]  
2、进入 target 启动 jar

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

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 8]  
打开浏览器访问 localhost:9877，如果报错如下：  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 9]  
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=9876/tcp --permanent
    systemctl restart firewalld.service
    firewall-cmd --reload

重新启动控制台项目

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 10]

### 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("myproducer-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，可以开放 10911 端口

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

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("myconsumer-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

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

### 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.southwind.configuration;
    
    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 org.springframework.web.server.ServerWebExchange;
    import reactor.core.publisher.Mono;
    
    import javax.annotation.PostConstruct;
    import java.util.*;
    
    @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
        @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
        @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 = new BlockRequestHandler() { 
                @Override
                public Mono<ServerResponse> handleRequest(ServerWebExchange serverWebExchange, Throwable throwable) { 
                    Map 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.southwind.configuration;
    
    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 org.springframework.web.server.ServerWebExchange;
    import reactor.core.publisher.Mono;
    
    import javax.annotation.PostConstruct;
    import java.util.*;
    
    @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
        @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
        @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 = new BlockRequestHandler() { 
                @Override
                public Mono<ServerResponse> handleRequest(ServerWebExchange serverWebExchange, Throwable throwable) { 
                    Map 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（事务回滚） ###

1、下载

2、解压，修改两个文件  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 11]  
regisry.conf

registry {
      type = "nacos"
      nacos {
        serverAddr = "localhost"
        namespace = "public"
        cluster = "default"
      }
    }
    
    config {
      type = "nacos"
      nacos {
        serverAddr = "localhost"
        namespace = "public"
        cluster = "default"
      }
    }

nacos-config.txt  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 12]  
3、启动 Nacos，运行 nacos-config.sh 将 Seata 配置导入 Nacos

进入 conf，右键 Git Bash Here

cd conf
    sh nacos-config.sh 127.0.0.1

执行成功，刷新 Nacos，配置加入（如下图）  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 13]  
nacos-config.txt 配置已生效  
![在这里插入图片描述][8c498b88c79442ab8505f01d356161e3.png]  
4、启动 Seata Server， **JDK 8 以上环境无法启动**

cd bin
    seata-server.bat -p 8090 -m file

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 14]  
启动成功，Nacos 注册成功。  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 15]  
Seata 服务环境搭建完毕，接下来去应用中添加。

1、初始化数据库，在两个数据库中添加事务日志记录表，SQL Seata 已经提供。

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 16]  
2、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,
      `ext` varchar(100) DEFAULT NULL,
      PRIMARY KEY (`id`),
      UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

3、两个工程的 pom.xml 添加 Seata 组件和 Nacos Config 组件。

<dependency>
        <groupId>com.alibaba.cloud</groupId>
        <artifactId>spring-cloud-starter-alibaba-seata</artifactId>
        <version>2.1.1.RELEASE</version>
    </dependency>
    
    <dependency>
        <groupId>com.alibaba.cloud</groupId>
        <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
    </dependency>

4、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));
        }
    
    }

5、将 registry.conf 复制到两个工程的 resources 下。

6、给两个工程添加 bootstrap.yml 读取 Nacos 配置。

spring:
      application:
        name: order
      cloud:
        nacos:
          config:
            server-addr: localhost:8848
            namespace: public
            group: SEATA_GROUP
        alibaba:
          seata:
            tx-service-group: ${ spring.application.name}

spring:
      application:
        name: pay
      cloud:
        nacos:
          config:
            server-addr: localhost:8848
            namespace: public
            group: SEATA_GROUP
        alibaba:
          seata:
            tx-service-group: ${ spring.application.name}

tx-service-group 需要和 Nacos 配置中的名称一致。  
![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAbW9ua2V5aGxq_size_20_color_FFFFFF_t_70_g_se_x_16 17]  
7、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";
        }
    }

【视频参考】[https://www.bilibili.com/video/BV1Mt4y1i7JW][https_www.bilibili.com_video_BV1Mt4y1i7JW]  
【源码参考】[https://github.com/monkeyhlj/spring-study][https_github.com_monkeyhlj_spring-study]

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[https_www.bilibili.com_video_BV1Mt4y1i7JW]: https://www.bilibili.com/video/BV1Mt4y1i7JW
[https_github.com_monkeyhlj_spring-study]: https://github.com/monkeyhlj/spring-study