Redis基本数据类型Hash Hashkey-value键值对key-map===>此时将value换成了一个map集合hash的本质与String没有太大的区别127.0.0.1:6379> hset hash field nihao #set一个具体的key-value (integer) 1 127.0.0.1:6379> hget hash field "nihao" 127.0.0.1:6379> hmset myhash field01 nihao filed02 xiexie #set多个key-value OK 127.0.0.1:6379> hmget myhash field01 filed02 #获取多个字段值 1) "nihao" 2) "xiexie" 127.0.0.1:6379> hgetall myhash #获取全部的数据 1) "field01" 2) "nihao" 3) "filed02" 4) "xiexie" 127.0.0.1:6379> # hdel 删除hash指定key字段，key对应的value值也同时被删除 127.0.0.1:6379> hdel myhash filed02 (integer) 1 127.0.0.1:6379> hgetall myhash 1) "field01" 2) "nihao" 127.0.0.1:6379> # hlen 获取hash表的字段数量 127.0.0.1:6379> hgetall myhash 1) "field01" 2) "nihao" 3) "field02" 4) "xiexie" 127.0.0.1:6379> hlen myhash (integer) 2 # hexists 判断hash中指定字段是否存在 127.0.0.1:6379> hgetall myhash 1) "field01" 2) "nihao" 3) "field02" 4) "xiexie" 127.0.0.1:6379> hexists myhash field01 (integer) 1 127.0.0.1:6379> 127.0.0.1:6379> hkeys myhash #只获取所有的field字段 1) "field01" 2) "field02" 127.0.0.1:6379> hvals myhash #只获取所有的value值 1) "nihao" 2) "xiexie" 127.0.0.1:6379> 127.0.0.1:6379> hset myhash field03 2 (integer) 1 127.0.0.1:6379> hincrby myhash field03 1 #设置自增 (integer) 3 127.0.0.1:6379> hsetnx myhash field04 ceshi #如果不存在则创建 (integer) 1 127.0.0.1:6379> hsetnx myhash field04 ceshi01 #如果存在则不能创建 (integer) 0 hash更适合对象的存储（如：用户信息变更，经常改动的数据等），String更适合字符串的存储。

Redis基本数据类型Set Set（集合）set中的值不能重读，与list操作一样，set操作以s开头127.0.0.1:6379> sadd set hello #添加值 (integer) 1 127.0.0.1:6379> sadd set world (integer) 1 127.0.0.1:6379> smembers set #查看指定set的所有值 1) "hello" 2) "world" 127.0.0.1:6379> sismember set hello #判断某一个值是否存在set集合中 (integer) 1 127.0.0.1:6379> scard set #获取set集合中内容元素的个数 (integer) 2 127.0.0.1:6379> # srem 移除元素 127.0.0.1:6379> smembers set #移除set集合中的指定元素 1) "hello1" 2) "hello2" 3) "hello" 4) "hello3" 127.0.0.1:6379> srem set hello (integer) 1 127.0.0.1:6379> smembers set 1) "hello1" 2) "hello2" 3) "hello3" 127.0.0.1:6379> # srandmember 随机抽取元素 127.0.0.1:6379> srandmember set #随机抽取一个元素 "hello1" 127.0.0.1:6379> srandmember set "hello2" 127.0.0.1:6379> srandmember set 2 #随机抽取指定个数的元素 1) "hello1" 2) "hello2" 127.0.0.1:6379> srandmember set 2 1) "hello" 2) "hello3" 127.0.0.1:6379> # spop 随机移除set集合中的元素 127.0.0.1:6379> spop set "hello3" 127.0.0.1:6379> spop set "hello" 127.0.0.1:6379> # smove 移动指定元素到其他set集合中 127.0.0.1:6379> sadd set01 hello (integer) 1 127.0.0.1:6379> sadd set01 bihao (integer) 1 127.0.0.1:6379> sadd set01 xiexie (integer) 1 127.0.0.1:6379> sadd set02 chouxiang (integer) 1 127.0.0.1:6379> smove set01 set02 xiexie (integer) 1 127.0.0.1:6379> smembers set01 1) "hello" 2) "bihao" 127.0.0.1:6379> smembers set02 1) "chouxiang" 2) "xiexie" 127.0.0.1:6379> # 差集 交集 并集 127.0.0.1:6379> smembers set01 1) "a" 2) "d" 3) "b" 4) "c" 5) "e" 127.0.0.1:6379> smembers set02 1) "b" 2) "c" 127.0.0.1:6379> sdiff set01 set02 #差集 1) "e" 2) "a" 3) "d" 127.0.0.1:6379> sinter set02 set02 #交集 1) "b" 2) "c" 127.0.0.1:6379> sunion set01 set02 #并集 1) "c" 2) "e" 3) "b" 4) "a" 5) "d" 具体应用如：共同关注，二度好友，（推荐好友，可能认识的人）六度分割理论

Redis基本数据类型List List（列表）所有的List命令都是以l开头的#插入 127.0.0.1:6379> lpush list a #将一个或多个值插入到列表头部 (integer) 1 127.0.0.1:6379> lpush list b (integer) 2 127.0.0.1:6379> lpush list c (integer) 3 127.0.0.1:6379> lrange list 0 -1 #range [key] 0 -1获取全部的值 1) "c" #后进先出（栈） 2) "b" 3) "a" 127.0.0.1:6379> lrange list 0 1 1) "c" 2) "b" 127.0.0.1:6379> rpush list d #rpush从头部插入 (integer) 4 127.0.0.1:6379> lrange list 0 -1 1) "c" 2) "b" 3) "a" 4) "d" 127.0.0.1:6379> #移除 127.0.0.1:6379> lrange list 0 -1 1) "c" 2) "b" 3) "a" 4) "d" 127.0.0.1:6379> lpop list #移除第一个元素 "c" 127.0.0.1:6379> lrange list 0 -1 1) "b" 2) "a" 3) "d" 127.0.0.1:6379> rpop list #移除最后一个元素（移除同样遵循栈后进先出的原则） "d" 127.0.0.1:6379> lrange list 0 -1 1) "b" 2) "a" 127.0.0.1:6379> #获取下标 127.0.0.1:6379> lrange list 0 -1 1) "b" 2) "a" 127.0.0.1:6379> lindex list 1 #通过下标获取list中的值[0,1,2,3...]，注意须于插入时的坐标区分 "a" 127.0.0.1:6379> lindex list 0 "b" 127.0.0.1:6379> # llen 长度 127.0.0.1:6379> lrange list 0 -1 1) "b" 2) "a" 127.0.0.1:6379> llen list (integer) 2 127.0.0.1:6379> # lrem 移除 127.0.0.1:6379> lrange list 0 -1 1) "c" 2) "b" 3) "a" 127.0.0.1:6379> lrem list 1 a #移除list集合中指定个数的value，精确匹配 (integer) 1 127.0.0.1:6379> lrange list 0 -1 1) "c" 2) "b" 127.0.0.1:6379> # ltrim 修剪 127.0.0.1:6379> lrange list 0 -1 1) "hello3" 2) "hello2" 3) "hello1" 4) "hello" 127.0.0.1:6379> ltrim list 1 2 #通过下标截取指定的长度，注：此时list的value已被改变，只剩下截取的元素 OK 127.0.0.1:6379> lrange list 0 -1 1) "hello2" 2) "hello1" 127.0.0.1:6379> # rpoplpush 移除列表的最后一个元素，并将它移动到新的列表中 127.0.0.1:6379> lrange list 0 -1 1) "hello3" 2) "hello2" 3) "hello1" 4) "hello" 127.0.0.1:6379> rpoplpush list otherlist "hello" 127.0.0.1:6379> lrange list 0 -1 1) "hello3" 2) "hello2" 3) "hello1" 127.0.0.1:6379> lrange otherlist 0 -1 1) "hello" 127.0.0.1:6379> # lset 将列表中指定下标的值替换为另一个值（更新） 127.0.0.1:6379> exists list #先判断列表是否存在 (integer) 0 127.0.0.1:6379> lset list 0 hello #如果列表不存在，则会报错 (error) ERR no such key 127.0.0.1:6379> lpush list hello (integer) 1 127.0.0.1:6379> lrange list 0 -1 1) "hello" 127.0.0.1:6379> lset list 0 nihao #如果存在，更新当前下标的值 OK 127.0.0.1:6379> lrange list 0 -1 1) "nihao" 127.0.0.1:6379> lset list 1 xiexie #如果要更新值的下标不存在，则报错 (error) ERR index out of range 127.0.0.1:6379> # linsert 将具体的值插入到列表中某个元素的前面或后面 127.0.0.1:6379> lrange list 0 -1 1) "hello" 2) "world" 127.0.0.1:6379> linsert list before world sunxiaochuan (integer) 3 127.0.0.1:6379> lrange list 0 -1 1) "hello" 2) "sunxiaochuan" 3) "world" 127.0.0.1:6379> linsert list after world liubo (integer) 4 127.0.0.1:6379> lrange list 0 -1 1) "hello" 2) "sunxiaochuan" 3) "world" 4) "liubo" 127.0.0.1:6379>

Redis基本数据类型String String127.0.0.1:6379> set name sunxiaochuan OK 127.0.0.1:6379> get name "sunxiaochuan" 127.0.0.1:6379> append name ",chouxiang" #追加字符串，如果当前字符串不存在，就相当于set key (integer) 22 127.0.0.1:6379> get name "sunxiaochuan,chouxiang" 127.0.0.1:6379> strlen name #获取字符串长度 (integer) 22 #自增 i++ #步长 i+= 127.0.0.1:6379> incr views #自增1 (integer) 1 127.0.0.1:6379> incr views (integer) 2 127.0.0.1:6379> decr views (integer) 1 127.0.0.1:6379> decr views (integer) 0 127.0.0.1:6379> decr views (integer) -1 127.0.0.1:6379> decrby views 5 #设置步长 (integer) -6 127.0.0.1:6379> incrby views 10 (integer) 4 127.0.0.1:6379> #字符串范围 range 127.0.0.1:6379> set test "hello world" OK 127.0.0.1:6379> get test "hello world" 127.0.0.1:6379> getrange test 0 5 #截取字符串[0,5] "hello " 127.0.0.1:6379> 127.0.0.1:6379> getrange test 0 -1 #获取全部字符串 "hello world" 127.0.0.1:6379> #替换 127.0.0.1:6379> set name sunxiaochuan OK 127.0.0.1:6379> get name "sunxiaochuan" 127.0.0.1:6379> setrange name 1 abc #替换指定位置开始的字符串 (integer) 12 127.0.0.1:6379> get name "sabciaochuan" 127.0.0.1:6379> #setex(set with expire) #设置过期时间 #setnx(set if not exist) #如果不存在，设置值为xxx 127.0.0.1:6379> setex name 10 "liubo" #设置name的值为liubo，10秒后过期 OK 127.0.0.1:6379> ttl name (integer) 7 127.0.0.1:6379> get name (nil) 127.0.0.1:6379> setnx name01 "sun" #如果name01不存在，则创建 (integer) 1 127.0.0.1:6379> keys * 1) "name01" 127.0.0.1:6379> setnx name01 "liu" #name01已存在，再次创建时失败 (integer) 0 127.0.0.1:6379> get name01 "sun" 127.0.0.1:6379> 127.0.0.1:6379> mset A a B b C c #同时设置多个值 OK 127.0.0.1:6379> keys * 1) "B" 2) "A" 3) "C" 127.0.0.1:6379> mget A B C #同时获取多个值 1) "a" 2) "b" 3) "c" 127.0.0.1:6379> msetnx A a D d #msetnx是一个原子性操作，要么都成功，要么都失败 (integer) 0 127.0.0.1:6379> get D (nil) 127.0.0.1:6379> #对象 #设置一个id为1的对象，json字符串来保存属性，方式一 127.0.0.1:6379> set user:1 {name:ceshi,age:3} #方式二 user:{id}:{filed} 127.0.0.1:6379> mset user:1:name ceshi user:1:age 3 OK 127.0.0.1:6379> mget user:1:name user:1:age 1) "ceshi" 2) "3" 127.0.0.1:6379> #getset 先get再set 127.0.0.1:6379> getset name sunxiaochuan #如果不存在值，返回null (nil) 127.0.0.1:6379> get name "sunxiaochuan" 127.0.0.1:6379> getset name liubo #如果存在值，获取原来的值，并设置新的值 "sunxiaochuan" 127.0.0.1:6379> get name "liubo" 127.0.0.1:6379> String除了以上用法，还可以用于计数器，多单位数量统计等。

Spring Cloud Config分布式配置中心 Spring Cloud ConfigSpring Cloud Config为微服务架构中的微服务提供集中化的外部配置支持，配置服务器为各个不同微服务应用的所有环节提供了一个中心化的外部配置。Spring Cloud Config分为客户端和服务端：服务端：分布式配置中心，它是一个独立的微服务应用，用来连接配置服务器，并为客户端提供获取配置信息，加密，解密信息等访问接口客户端：通过指定的配置中心来管理应用资源，以及与业务相关的配置内容，并在启动的时候从配置中心获取和加载配置信息。配置服务器默认采用git来存储配置信息，这样有助于对环境配置进行版本管理。作用：集中管理配置文件不同环境，不同配置，动态化的配置更新，分环境部署，如：开发、测试、生产等环境运行期间可以动态调整配置，不再需要在每个服务部署的机器上编写配置文件，服务会向配置中心统一拉取配置自己的信息当配置发生变动时，服务节点不需要重启，动态应用新的配置配置信息以REST接口的形式暴露图片来源：狂神说Java具体实例1、服务端pom依赖：<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-config-server</artifactId> <version>2.1.1.RELEASE</version> </dependency> <!--actuator监控信息--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> </dependencies>application.yml配置：server: port: 3344 spring: application: name: springcloud-config-server #连接远程仓库 cloud: config: server: git: uri: https://github.com/suaxi/SpringCloud-config.gitSpringBoot启动类开启ConfigServer注解：package com.sw.springcloud; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.config.server.EnableConfigServer; /** * @Author suaxi * @Date 2020/12/30 14:49 */ @SpringBootApplication @EnableConfigServer public class Config_Server_3344 { public static void main(String[] args) { SpringApplication.run(Config_Server_3344.class,args); } } 2、客户端pom依赖：<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-config</artifactId> <version>2.1.1.RELEASE</version> </dependency> <!--actuator监控信息--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> </dependencies>bootstrap.yml配置：#系统级别的配置 spring: cloud: config: name: config-client #需要从远程仓库读取的资源名称 profile: dev #版本 label: master #分支 uri: http://localhost:3344 #获取配置信息的地址（Config配置服务端）application.yml配置：#用户级别的配置 spring: application: name: springcloud-config-client-3355Controller（配置REST接口）package com.sw.springcloud.controller; import org.springframework.beans.factory.annotation.Value; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; /** * @Author suaxi * @Date 2020/12/30 15:29 */ @RestController public class ConfigClientController { @Value("${spring.application.name}") private String applicationName; @Value("${eureka.client.service-url.defaultZone}") private String eurekaServer; @Value("${server.port}") private String port; @RequestMapping("/config") public String getConfig(){ return "applicationName:"+applicationName+ "eurekaServer:"+eurekaServer+ "port:"+port; } } 3、Eureka服务注册中心pom依赖：<dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka-server</artifactId> <version>1.4.7.RELEASE</version> </dependency> <!--config--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-config</artifactId> <version>2.1.1.RELEASE</version> </dependency> </dependencies>bootstrap.yml配置：与config配置中心的客户端一致，都是从Config服务端获取配置信息spring: cloud: config: name: config-eureka label: master profile: dev uri: http://localhost:3344application.yml配置：spring: application: name: springcloud-config-eureka-7001SpringBoot启动类：package com.sw.springcloud; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer; /** * @Author suaxi * @Date 2020/12/29 11:02 */ @SpringBootApplication @EnableEurekaServer //服务端 public class EurekaConfigServer_7001 { public static void main(String[] args) { SpringApplication.run(EurekaConfigServer_7001.class,args); } } 4、Eureka服务提供者pom依赖：<dependencies> <!--需要拿到实体类，配置api module--> <dependency> <groupId>com.sw</groupId> <artifactId>springcloud-api</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-core</artifactId> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jetty</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> <version>1.4.7.RELEASE</version> </dependency> <!--actuator监控信息--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-hystrix</artifactId> <version>1.4.7.RELEASE</version> </dependency> <!--config--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-config</artifactId> <version>2.1.1.RELEASE</version> </dependency> </dependencies>bootstrap.yml配置：与以上两个的配置一致，都是从Config服务端获取配置信息spring: cloud: config: name: config-dept label: master profile: dev uri: http://localhost:3344application.yml配置：spring: application: name: springcloud-config-dept-8088服务提供者对比之前的配置（application.yml）：通过Config分布式配置中心，将配置文件放到git统一管理，现只需从Config-server获取即可server: port: 8088 #mybatis配置 mybatis: type-aliases-package: com.sw.springcloud.pojo config-location: classpath:mybatis/mybatis-config.xml mapper-locations: classpath:mybatis/mapper/*.xml #Spring配置 spring: application: name: springcloud-provider-dept datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://localhost:3306/db01?useUnicode=true&character=UFT-8 username: root password: 123456 #配置Eureka，配置服务注册到哪里 eureka: client: service-url: defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/ instance: instance-id: springcloud-provider_dept8088 #修改Eureka默认描述信息 prefer-ip-address: true #显示服务的真实ip地址，替换原先的localhost #info配置 info: app.name: springcloud-demo company.name: suaxi 配置文件交由git统一管理

Zuul路由网关 Zuul路由网关Zuul包含对请求的路由和过滤两个功能：路由功能：负责将外部请求转发到具体的微服务实例上，实现外部访问入口统一过滤：对请求的处理过程进行干预，是实现请求校验，服务聚合等功能的基础注：Zuul服务也会注册到Eureka服务注册中心1、导入依赖<dependencies> <!--zuul--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-zuul</artifactId> <version>1.4.7.RELEASE</version> </dependency> <!--hystrix--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-hystrix</artifactId> <version>1.4.7.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-hystrix-dashboard</artifactId> <version>1.4.7.RELEASE</version> </dependency> <!--Ribbon--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-ribbon</artifactId> <version>1.4.7.RELEASE</version> </dependency> <!--Eureka--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> <version>1.4.7.RELEASE</version> </dependency> <dependency> <groupId>com.sw</groupId> <artifactId>springcloud-api</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> </dependencies>2、application.yml配置server: port: 8888 spring: application: name: springcloud-zuul eureka: client: service-url: defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/ instance: instance-id: zuul8888.com prefer-ip-address: true info: app.name: springcloud-demo company.name: suaxi zuul: routes: mydept.serviceID: springcloud-provider-dept mydept.path: /mydept/** ignored-services: "*" #ignored-services: springcloud-provider-dept禁止使用原来的微服务名访问 #设置为 * 表示禁止使用全部的微服务ID进行访问3、SpringBoot启动类开启Zuul注解一般使用@EnableZuulProxypackage com.sw.springcloud; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.zuul.EnableZuulProxy; /** * @Author suaxi * @Date 2020/12/30 10:50 */ @SpringBootApplication @EnableZuulProxy //开启Zuul路由网关 public class ZuulApplication_8888 { public static void main(String[] args) { SpringApplication.run(ZuulApplication_8888.class,args); //http://www.xxx.com:8888/mydept/dept/get/1 } } 开启Zuul路由网关后，可通过：域名+端口号 访问微服务项目

Hystrix服务降级 Hystrix服务降级A、B、C三台服务器，A在某一时间段的负载很重，急需扩容，而此时间段B、C负载很小或没有访问量，需关闭其中的服务器，拿去给A扩容，以降低负载，同时设置fallback回调，让这个时间段需要访问B、C服务器的用户得到“服务暂时不可用或关闭”的信息，这个过程可以简单的比喻为服务降级。1、API接口设置fallback回调pojopackage com.sw.springcloud.pojo; import lombok.Data; import lombok.NoArgsConstructor; import lombok.experimental.Accessors; import java.io.Serializable; /** * @Author suaxi * @Date 2020/12/28 21:07 */ @Data @NoArgsConstructor @Accessors(chain = true) //链式编程 public class Dept implements Serializable { private Long deptno; private String dname; private String db_source; //数据存在哪个数据库 public Dept(String dname) { this.dname = dname; } } service接口package com.sw.springcloud.service; import com.sw.springcloud.pojo.Dept; import org.springframework.cloud.openfeign.FeignClient; import org.springframework.stereotype.Component; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.PostMapping; import java.util.List; /** * @Author suaxi * @Date 2020/12/29 20:02 */ @Component @FeignClient(value = "SPRINGCLOUD-PROVIDER-DEPT",fallbackFactory = DeptClientServiceFallbackFactory.class) public interface DeptClientService { @GetMapping("/dept/get/{id}") public Dept findById(@PathVariable("id")Long id); @GetMapping("/dept/list") public List<Dept> findAll(); @PostMapping("/dept/add") public boolean addDept(Dept dept); } FallbackFactoryService服务降级设置package com.sw.springcloud.service; import com.sw.springcloud.pojo.Dept; import feign.hystrix.FallbackFactory; import org.springframework.stereotype.Component; import java.util.List; /** * @Author suaxi * @Date 2020/12/30 9:33 * 服务降级 */ @Component public class DeptClientServiceFallbackFactory implements FallbackFactory { @Override public Object create(Throwable throwable) { return new DeptClientService() { @Override public Dept findById(Long id) { return new Dept() .setDeptno(id) .setDname("未查询到数据，该服务现已被关闭") .setDb_source("没有数据库信息"); } @Override public List<Dept> findAll() { return null; } @Override public boolean addDept(Dept dept) { return false; } }; } /* 服务熔断：服务端，某个服务超时或异常，引起熔断（类似于保险丝） 服务降级：客户端，从系统整体负载考虑，当某个服务熔断或关闭之后，服务将不再被调用 此时在客户端可以设置一个回调FallbackFactory，返回一个默认的缺省值，可以 提升用户体验，但服务质量随之下降 */ } 2、消费者端设置appliction.yml配置服务降级server: port: 80 eureka: client: register-with-eureka: false #不向注册中心注册自己（消费者端） service-url: defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/ #开启降级feign.hystrix feign: hystrix: enabled: true将RestTemplate注册到Spring容器中package com.sw.springcloud.config; import org.springframework.cloud.client.loadbalancer.LoadBalanced; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.client.RestTemplate; /** * @Author suaxi * @Date 2020/12/28 22:15 */ @Configuration public class ConfigBean { @Bean @LoadBalanced //注册Ribbon public RestTemplate getRestTemplate(){ return new RestTemplate(); } } SpringBoot启动类package com.sw.springcloud; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.EnableEurekaClient; import org.springframework.cloud.openfeign.EnableFeignClients; import org.springframework.context.annotation.ComponentScan; /** * @Author suaxi * @Date 2020/12/28 22:29 */ @SpringBootApplication @EnableEurekaClient @EnableFeignClients(basePackages = {"com.sw.springcloud"}) public class FeignDeptConsumer_80 { public static void main(String[] args) { SpringApplication.run(FeignDeptConsumer_80.class,args); } } 用户正常访问服务：微服务节点出现问题，服务降级：

Hystrix服务熔断 Hystrix服务熔断服务熔断：熔断机制是对应雪崩效应的一种微服务链路保护机制。当某个微服务不可用或响应时间太长，会进行服务的降级，进而熔断该节点微服务的调用，快速返回“错误的响应信息”，当该节点的调用恢复正常之后注册中心将其恢复至调用链路。Spring Cloud的熔断机制通过Hystrix实现，它会监控微服务间的调用状况，当失败的调用到一定阈值（缺省5秒内20次调用失败），就会启动熔断机制。具体实例：1、导入依赖<dependencies> <!--需要拿到实体类，配置api module--> <dependency> <groupId>com.sw</groupId> <artifactId>springcloud-api</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-core</artifactId> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jetty</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> <version>1.4.7.RELEASE</version> </dependency> <!--actuator监控信息--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> <!--Hystrix--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-hystrix</artifactId> <version>1.4.7.RELEASE</version> </dependency> </dependencies>2、daopackage com.sw.springcloud.dao; import com.sw.springcloud.pojo.Dept; import org.apache.ibatis.annotations.Mapper; import org.springframework.stereotype.Repository; import java.util.List; /** * @Author suaxi * @Date 2020/12/28 21:34 */ @Mapper @Repository public interface DeptDao { public boolean addDept(Dept dept); public Dept findDept(Long id); public List<Dept> findAll(); } 3、Service接口package com.sw.springcloud.service; import com.sw.springcloud.pojo.Dept; import java.util.List; /** * @Author suaxi * @Date 2020/12/28 21:34 */ public interface DeptService { public boolean addDept(Dept dept); public Dept findDept(Long id); public List<Dept> findAll(); } Service实现：package com.sw.springcloud.service; import com.sw.springcloud.dao.DeptDao; import com.sw.springcloud.pojo.Dept; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import java.util.List; /** * @Author suaxi * @Date 2020/12/28 21:42 */ @Service public class DeptServiceImpl implements DeptService{ @Autowired private DeptDao deptDao; @Override public boolean addDept(Dept dept) { return deptDao.addDept(dept); } @Override public Dept findDept(Long id) { return deptDao.findDept(id); } @Override public List<Dept> findAll() { return deptDao.findAll(); } } 4、controller注：hystrix熔断需开启注解@HystrixCommand(fallbackMethod = "hystrixGet")，且提供熔断后的备选方法package com.sw.springcloud.controller; import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand; import com.sw.springcloud.pojo.Dept; import com.sw.springcloud.service.DeptService; 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.PostMapping; import org.springframework.web.bind.annotation.RestController; import java.util.List; /** * @Author suaxi * @Date 2020/12/28 21:44 * 提供RestFul服务 */ @RestController public class DeptController { @Autowired private DeptService deptService; @GetMapping("/dept/get/{id}") @HystrixCommand(fallbackMethod = "hystrixGet") public Dept get(@PathVariable("id")Long id){ Dept dept = deptService.findDept(id); if (dept==null){ throw new RuntimeException("不存在id为"+id+"的用户，或者信息无法找到"); } return dept; } //熔断后的备选方法 public Dept hystrixGet(@PathVariable("id")Long id){ Dept dept = deptService.findDept(id); return new Dept() .setDeptno(id) .setDname("不存在id为"+id+"的用户，或者信息无法找到,null-->@Hystrix") .setDb_source("No message in MySQL"); } } 5、SpringBoot启动类开启Hystrix注解支持package com.sw.springcloud; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.cloud.netflix.eureka.EnableEurekaClient; /** * @Author suaxi * @Date 2020/12/28 21:49 */ @SpringBootApplication @EnableEurekaClient //服务启动后自动注册到Eureka中 @EnableDiscoveryClient //开启服务发现 @EnableCircuitBreaker //开启熔断器支持 public class DeptProviserHystrix_8088 { public static void main(String[] args) { SpringApplication.run(DeptProviserHystrix_8088.class,args); } } 6、appliction.yml配置（此处以单个节点配置为例，实际开发中的微服务节点不止一个）server: port: 8088 #mybatis配置 mybatis: type-aliases-package: com.sw.springcloud.pojo config-location: classpath:mybatis/mybatis-config.xml mapper-locations: classpath:mybatis/mapper/*.xml #Spring配置 spring: application: name: springcloud-provider-dept datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://localhost:3306/db01?useUnicode=true&character=UFT-8 username: root password: 123456 #配置Eureka，配置服务注册到哪里 eureka: client: service-url: defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/ instance: instance-id: springcloud-provider_dept-hystrix_8088 #修改Eureka默认描述信息 #info配置 info: app.name: springcloud-demo company.name: suaxi 当整个微服务调用出现问题时，前端反馈给用户的信息不是错误代码，而是熔断后的备选方法中定义的信息（即快速返回出现错误的响应信息）。用户正常查询信息：查询数据库中不存在的信息，即服务调用出现异常：