概述

注册中心-Spring Cloud Eureka

Eureka解决了：服务的管理，注册和发现、状态监管、动态路由

Eureka负责管理记录服务提供者的信息。服务调用者无需自己寻找服务，Eureka自动匹配服务给调用者

Eureka与服务之间通过心跳机制进行监控

负载均衡-Spring Cloud Ribbon

Ribbon是Netflix发布的负载均衡器，有助于控制HTTP客户端行为。为Ribbon配置服务提供者地址列表后，Ribbon就可基于负载均衡算法，自动帮助服务消费者请求

Ribbon默认提供的负载均衡算法：轮询、随机、重试法、加权。当然，我们可用自己定义负载均衡算法

熔断器-Spring Cloud Hystrix

Hystrix，英文意思是豪猪，全身是刺，刺是一种保护机制。Hystrix也是Netflix公司的一款组件。

Hystrix是Netflix开源的一个延迟和容错库，用于隔离访问远程服务、第三方库、防止出现级联失败也就是雪崩效应。

预览

环境准备

-- 使用springcloud数据库
USE springcloud;
-- ----------------------------
-- Table structure for tb_user
-- ----------------------------
CREATE TABLE `tb_user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(100) DEFAULT NULL COMMENT '用户名',
  `password` varchar(100) DEFAULT NULL COMMENT '密码',
  `name` varchar(100) DEFAULT NULL COMMENT '姓名',
  `age` int(11) DEFAULT NULL COMMENT '年龄',
  `sex` int(11) DEFAULT NULL COMMENT '性别，1男，2女',
  `birthday` date DEFAULT NULL COMMENT '出生日期',
  `created` date DEFAULT NULL COMMENT '创建时间',
  `updated` date DEFAULT NULL COMMENT '更新时间',
  `note` varchar(1000) DEFAULT NULL COMMENT '备注',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8 COMMENT='用户信息表';
-- ----------------------------
-- Records of tb_user
-- ----------------------------
INSERT INTO `tb_user` VALUES ('1', 'zhangsan', '123456', '张三', '13', '1', '2006-08-01', '2019-05-16', '2019-05-16', '张三');
INSERT INTO `tb_user` VALUES ('2', 'lisi', '123456', '李四', '13', '1', '2006-08-01', '2019-05-16', '2019-05-16', '李四');

springcloud-parent

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.lichun</groupId>
    <artifactId>springcloud-parent</artifactId>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>springcloud-provider</module>
        <module>springcloud-provider-demo01</module>
        <module>springcloud-consumer</module>
        <module>eureka-server</module>
    </modules>
    <packaging>pom</packaging>


    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.4.RELEASE</version>
    </parent>

    <!--SpringCloud包依赖管理-->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Greenwich.SR1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

</project>

eureka-server

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud-parent</artifactId>
        <groupId>com.lichun</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>eureka-server</artifactId>

    <!--依赖包-->
    <dependencies>
        <!--eureka-server依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
    </dependencies>

</project>

application.yaml

server:
  port: 7001
spring:
  application:
    name: eureka-server            # 应用名称，在Eureka中作为服务的id标识（serviceId）
eureka:
  client:
    register-with-eureka: false   # 是否将自己注册到Eureka中
    fetch-registry: false         # 是否从eureka中获取服务信息
    service-url:
      defaultZone: http://localhost:7001/eureka   # EurekaServer的地址
  server:
    # 关闭自我保护模式（默认是打开）
    # enable-self-preservation: false
    # 对无效的服务进行剔除操作，单位是毫秒
    # eviction-interval-timer-in-ms: 5000

EurekaServerApplication.java

package com.lichun;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer     // 开启Eureka服务
public class EurekaServerApplication {

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

springcloud-provider

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud-parent</artifactId>
        <groupId>com.lichun</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-producer</artifactId>


    <dependencies>
        <!--eureka客户端-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.1</version>
        </dependency>
        <!--web起步包-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--MySQL驱动包-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!--测试包-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

application.yaml

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/springcloud?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: root
  application:
    # 服务的名字,不同应用的名字不同。如果是集群，名字需要相同
    name: springcloud-provider

#指定eureka服务地址
eureka:
  client:
    service-url:
      # EurekaServer的地址
      defaultZone: http://localhost:7001/eureka
  registry-fetch-interval-seconds: 30
  instance:
    # 指定IP地址
    ip-address: 127.0.0.1
    # 访问服务的时候，推荐使用IP
    prefer-ip-address: true
    # 租约到期，服务时效时间，默认值90秒
    # 服务超过90秒没有发生心跳，EurekaServer会将服务从列表移除[前提是EurekaServer关闭了自我保护]
    lease-expiration-duration-in-seconds: 90
    # 租约续约间隔时间，默认30秒
    lease-renewal-interval-in-seconds: 30

server:
  port: 18081

ProviderApplication.java

package com.lichun;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

@SpringBootApplication
@MapperScan(basePackages = "com.lichun.dao")
// @EnableDiscoveryClient  // 开启Eureka客户端发现功能
@EnableEurekaClient     // 开启Eureka客户端发现功能，注册中心只能是Eureka
public class ProviderApplication {
    public static void main(String[] args) {
        SpringApplication.run(ProviderApplication.class, args);
    }
}

User.java

package com.lichun.pojo;

import java.util.Date;

public class User {
    private Integer id;             // 主键id
    private String username;        // 用户名
    private String password;        // 密码
    private String name;            // 姓名
    private Integer age;            // 年龄
    private Integer sex;            // 性别
    private Date birthday;          // 出生日期
    private Date created;           // 创建时间
    private Date updated;           // 更新时间
    private String note;            // 备注

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getSex() {
        return sex;
    }

    public void setSex(Integer sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public Date getCreated() {
        return created;
    }

    public void setCreated(Date created) {
        this.created = created;
    }

    public Date getUpdated() {
        return updated;
    }

    public void setUpdated(Date updated) {
        this.updated = updated;
    }

    public String getNote() {
        return note;
    }

    public void setNote(String note) {
        this.note = note;
    }
}

UserDao.java

package com.lichun.dao;

import com.lichun.pojo.User;
import org.apache.ibatis.annotations.Select;

public interface UserDao {

    @Select("select * from tb_user where id=#{id}")
    public User findById(Integer id);
}

UserService.java

package com.lichun.service;

import com.lichun.pojo.User;

public interface UserService {
    public User findById(Integer id);
}

UserServiceImpl.java

package com.lichun.service.impl;

import com.lichun.dao.UserDao;
import com.lichun.pojo.User;
import com.lichun.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao;

    @Override
    public User findById(Integer id) {
        return userDao.findById(id);
    }
}

UserController.java

package com.lichun.controller;

import com.lichun.pojo.User;
import com.lichun.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping("/{id}")
    public User findById(@PathVariable(value = "id") Integer id) {
        User user = userService.findById(id);
        String username = user.getUsername();
        user.setUsername(username + " provider");
        return user;
    }
}

springcloud-provider-demo01

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud-parent</artifactId>
        <groupId>com.lichun</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-producer-demo01</artifactId>


    <dependencies>
        <!--eureka客户端-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.1</version>
        </dependency>
        <!--web起步包-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--MySQL驱动包-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!--测试包-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

application.yaml

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/springcloud?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: root
  application:
    # 服务的名字,不同应用的名字不同。如果是集群，名字需要相同
    name: springcloud-provider

#指定eureka服务地址
eureka:
  client:
    service-url:
      # EurekaServer的地址
      defaultZone: http://localhost:7001/eureka
  registry-fetch-interval-seconds: 30
  instance:
    # 指定IP地址
    ip-address: 127.0.0.1
    # 访问服务的时候，推荐使用IP
    prefer-ip-address: true
    # 租约到期，服务时效时间，默认值90秒
    # 服务超过90秒没有发生心跳，EurekaServer会将服务从列表移除[前提是EurekaServer关闭了自我保护]
    lease-expiration-duration-in-seconds: 90
    # 租约续约间隔时间，默认30秒
    lease-renewal-interval-in-seconds: 30

server:
  port: 18083

ProviderApplication.java

package com.lichun;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

@SpringBootApplication
@MapperScan(basePackages = "com.lichun.dao")
// @EnableDiscoveryClient  // 开启Eureka客户端发现功能
@EnableEurekaClient     // 开启Eureka客户端发现功能，注册中心只能是Eureka
public class ProviderApplication {
    public static void main(String[] args) {
        SpringApplication.run(ProviderApplication.class, args);
    }
}

User.java

package com.lichun.pojo;

import java.util.Date;

public class User {
    private Integer id;             // 主键id
    private String username;        // 用户名
    private String password;        // 密码
    private String name;            // 姓名
    private Integer age;            // 年龄
    private Integer sex;            // 性别
    private Date birthday;          // 出生日期
    private Date created;           // 创建时间
    private Date updated;           // 更新时间
    private String note;            // 备注

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getSex() {
        return sex;
    }

    public void setSex(Integer sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public Date getCreated() {
        return created;
    }

    public void setCreated(Date created) {
        this.created = created;
    }

    public Date getUpdated() {
        return updated;
    }

    public void setUpdated(Date updated) {
        this.updated = updated;
    }

    public String getNote() {
        return note;
    }

    public void setNote(String note) {
        this.note = note;
    }
}

UserDao.java

package com.lichun.dao;

import com.lichun.pojo.User;
import org.apache.ibatis.annotations.Select;

public interface UserDao {

    @Select("select * from tb_user where id=#{id}")
    public User findById(Integer id);
}

UserService.java

package com.lichun.service;

import com.lichun.pojo.User;

public interface UserService {
    public User findById(Integer id);
}

UserServiceImpl.java

package com.lichun.service.impl;

import com.lichun.dao.UserDao;
import com.lichun.pojo.User;
import com.lichun.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao;

    @Override
    public User findById(Integer id) {
        return userDao.findById(id);
    }
}

UserController.java

package com.lichun.controller;

import com.lichun.pojo.User;
import com.lichun.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping("/{id}")
    public User findById(@PathVariable(value = "id") Integer id) {
        User user = userService.findById(id);
        String username = user.getUsername();
        user.setUsername(username + " provider-demo01");
        return user;
    }
}

springcloud-consumer

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud-parent</artifactId>
        <groupId>com.lichun</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-consumer</artifactId>

    <!--依赖包-->
    <dependencies>
        <!--熔断器-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>

        <!--eureka客户端-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <!--web起步依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

</project>

application.yml

server:
  port: 18082
spring:
  application:
    name: springcloud-consumer
eureka:
  client:
    service-url:
      # EurekaServer的地址
      defaultZone: http://localhost:7001/eureka

ConsumerApplication.java

package com.lichun;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
// @EnableDiscoveryClient   // 开启Eureka客户端发现功能
@EnableEurekaClient         // 开启Eureka客户端发现功能，注册中心只能是Eureka
@EnableCircuitBreaker       // 开启熔断
public class ConsumerApplication {
    public static void main(String[] args) {
        SpringApplication.run(ConsumerApplication.class, args);
    }

    @Bean
    // 开启负载均衡
    @LoadBalanced
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

User.java

package com.lichun.pojo;

import java.util.Date;

public class User {
    private Integer id;             // 主键id
    private String username;        // 用户名
    private String password;        // 密码
    private String name;            // 姓名
    private Integer age;            // 年龄
    private Integer sex;            // 性别
    private Date birthday;          // 出生日期
    private Date created;           // 创建时间
    private Date updated;           // 更新时间
    private String note;            // 备注

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getSex() {
        return sex;
    }

    public void setSex(Integer sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public Date getCreated() {
        return created;
    }

    public void setCreated(Date created) {
        this.created = created;
    }

    public Date getUpdated() {
        return updated;
    }

    public void setUpdated(Date updated) {
        this.updated = updated;
    }

    public String getNote() {
        return note;
    }

    public void setNote(String note) {
        this.note = note;
    }
}

UserController.java

package com.lichun.controller;

import com.lichun.pojo.User;
import com.netflix.hystrix.contrib.javanica.annotation.DefaultProperties;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import java.util.List;

@RestController
@RequestMapping(value = "/consumer")
// @DefaultProperties(defaultFallback = "defaultFallback")
public class UserController {

    @Autowired
    private RestTemplate restTemplate;

    // 注入该对象，可以用来发现当前注册中心中的服务对象
    @Autowired
    private DiscoveryClient discoveryClient;

    @GetMapping(value = "/{id}")
    // 在有可能发生问题的方法上添加降级处理调用
    @HystrixCommand(fallbackMethod = "fallBack")
    // @HystrixCommand
    public User findById(@PathVariable(value = "id") Integer id) {
        /*String url = "http://localhost:18081/user/" + id;
        return restTemplate.getForObject(url, User.class);*/

        /*// 获取指定实例
        List<ServiceInstance> instances = discoveryClient.getInstances("SPRINGCLOUD-PROVIDER");
        // 获取第一个实例对象
        ServiceInstance serviceInstance = instances.get(0);
        // 拼接服务地址
        String instanceURL = "http://" + serviceInstance.getHost() + ":" + serviceInstance.getPort() + "/user/" + id;
        System.out.println(instanceURL);*/

        String instanceURL = "http://SPRINGCLOUD-PROVIDER/user/" + id;
        return restTemplate.getForObject(instanceURL, User.class);
    }

    public User fallBack(Integer id) {
        User user = new User();
        user.setId(id);
        user.setUsername("服务降级,默认处理！");
        return user;
    }

    // 创建一个全局默认的兜底的方法 方法 一定不能有参数
    public User defaultFallback(){
        User user = new User();
        user.setId(0);
        user.setName("匿名用户全局默认值");
        return user;
    }
}