SpringCloud--02、SpringCloud入门

版权声明：转载请注明原始链接 https://blog.csdn.net/sswqzx/article/details/84730113

一、SpringCloud简介

微服务是一种架构方式，最终肯定需要技术架构去实施。

微服务的实现方式很多，但是最火的莫过于Spring Cloud、其次是dubbo

SpringCloud是Spring旗下的项目之一 、它只是将一些非常流行的持术整合到一起、如、路由、负载、熔断器。。。

SpringCloud主要涉及的组件包括：

Spring Cloud Netflix：核心组件
- Eureka：注册中心 
- Zuul：服务网关
- Ribbon：负载均衡
- Feign：服务调用
- Hystix：熔断器

其它组件：
- SpringCloud config : 配置中心
- SpringCloud Sleuth : 服务链追踪
- SpringBoot Admin : 微服务监控
- SpringBoot Security：安全组件
- SpringCloud OAuth2/JWT ：保护微服务系统

架构图： 

SpringCloud版本说明：

最早的Release版本：Angel，第二个Release版本：Brixton，然后是Camden、Dalston、Edgware，目前最新的是Finchley版本。

 二、微服务场景模拟

1、创建父工程

pom.xml 对大部分要用到的依赖的版本进行了 管理，方便后续使用

<?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.baidus.demo</groupId>
    <artifactId>cloud-demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>user-service</module>
        <module>consumer-demo</module>
        <module>eureka-server</module>
        <module>zuul-demo</module>
    </modules>
    <packaging>pom</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath/>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Finchley.SR1</spring-cloud.version>
        <mybatis.starter.version>1.3.2</mybatis.starter.version>
        <mapper.starter.version>2.0.2</mapper.starter.version>
        <druid.starter.version>1.1.9</druid.starter.version>
        <mysql.version>5.1.32</mysql.version>
        <pageHelper.starter.version>1.2.3</pageHelper.starter.version>
        <leyou.latest.version>1.0.0-SNAPSHOT</leyou.latest.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <!-- springCloud -->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- mybatis启动器 -->
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>${mybatis.starter.version}</version>
            </dependency>
            <!-- 通用Mapper启动器 -->
            <dependency>
                <groupId>tk.mybatis</groupId>
                <artifactId>mapper-spring-boot-starter</artifactId>
                <version>${mapper.starter.version}</version>
            </dependency>
            <!-- 分页助手启动器 -->
            <dependency>
                <groupId>com.github.pagehelper</groupId>
                <artifactId>pagehelper-spring-boot-starter</artifactId>
                <version>${pageHelper.starter.version}</version>
            </dependency>
            <!-- mysql驱动 -->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

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

2、服务提供者

在父工程下创建module

pom.xml依赖

<?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>cloud-demo</artifactId>
        <groupId>cn.itcast.demo</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <groupId>cn.itcast.demo</groupId>
    <artifactId>user-service</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>tk.mybatis</groupId>
            <artifactId>mapper-spring-boot-starter</artifactId>
        </dependency>
    </dependencies>
</project>

 项目结构：

UserController.java

package com.baidus.user.contrlooer;

import com.baidus.user.pojo.User;
import com.baidus.user.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;

/**
 * @ Author     ：ShaoWei Sun.
 * @ Date       ：Created in 15:54 2018/12/1
 */
@RestController
@RequestMapping("user")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping("/{id}")
    public User queryById(@PathVariable("id") Long id){
        return userService.queryById(id);
    }
}

service:UserService.java

@Service
public class UserService {

    @Autowired
    private UserMapper userMapper;

    public User queryById(Long id) {
        return this.userMapper.selectByPrimaryKey(id);
    }
}

Mapper:UserMapper.java接口

package com.baidus.user.mapper;

import com.baidus.user.pojo.User;

/**
 * @ Author     ：ShaoWei Sun.
 * @ Date       ：Created in 16:01 2018/12/1
 */
public interface UserMapper extends tk.mybatis.mapper.common.Mapper<User> {
}

实体类：User.java

package com.baidus.user.pojo;

import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import java.io.Serializable;
import java.util.Date;

/**
 * @ Author     ：ShaoWei Sun.
 * @ Date       ：Created in 15:56 2018/12/1
 */

@Table(name = "tb_user")
public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    // 用户名
    private String userName;

    // 密码
    private String password;

    // 姓名
    private String name;

    // 年龄
    private Integer age;

    // 性别，1男性，2女性
    private Integer sex;

    // 出生日期
    private Date birthday;

    // 创建时间
    private Date created;

    // 更新时间
    private Date updated;

    public static long getSerialVersionUID() {
        return serialVersionUID;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long 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;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", userName='" + userName + '\'' +
                ", password='" + password + '\'' +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", sex=" + sex +
                ", birthday=" + birthday +
                ", created=" + created +
                ", updated=" + updated +
                '}';
    }
}

在resources目录看中创建application.yml属性文件

server:
  port: 8081

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mybatis
    username: root
    password: sswqzx
  application:
    name: user-service # 应用名称

mybatis:
  type-aliases-package: com.baidus.user.pojo

启动类：UserApp.java

package com.baidus.user;

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

/**
 * @ Author     ：ShaoWei Sun.
 * @ Date       ：Created in 16:08 2018/12/1
 */
@SpringBootApplication
@MapperScan("com.baidus.user.mapper")
@EnableDiscoveryClient //开启EurekaClient功能
public class UserApp {
    public static void main(String[] args) {
        SpringApplication.run(UserApp.class,args);
    }
}

启动项目、访问http://localhost:8081/user/7

3、服务调用者

创建服务调用者module

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>cloud-demo</artifactId>
        <groupId>com.baidus.demo</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.baidus.demo</groupId>
    <artifactId>consumer-demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- 添加OkHttp支持 -->
        <dependency>
            <groupId>com.squareup.okhttp3</groupId>
            <artifactId>okhttp</artifactId>
            <version>3.9.0</version>
        </dependency>
    </dependencies>

</project>

项目结构：

ConsumerController.java

@RestController
@RequestMapping("consume")
public class ConsumerController {

    @Autowired
    private UserService userService;

    @GetMapping
    public List<User> consume(@RequestParam("ids") List<Long> ids) {
        return this.userService.queryUserByIds(ids);
    }
}

UserDao.java

@Component
public class UserDao {

    @Autowired
    private RestTemplate restTemplate;

    public User queryUserById(Long id){
        String url = "http://localhost:8081/user/" + id;
        return this.restTemplate.getForObject(url, User.class);
    }
}

User.java

UserService.java

@Service
public class UserService {

    @Autowired
    private UserDao userDao;

    public List<User> queryUserByIds(List<Long> ids){
        List<User> users = new ArrayList<>();
        for (Long id : ids) {
            User user = this.userDao.queryUserById(id);
            users.add(user);
        }
        return users;
    }
}

application.yml 全局配置文件

server:
  port: 8080

spring:
  application:
    name: consumer # 应用名称

consumerDemoApp.java 启动类

@SpringBootApplication
public class ConsumerDemoApplication {

    @Bean
    public RestTemplate restTemplate() {
        // 这次我们使用了OkHttp客户端,只需要注入工厂即可
        return new RestTemplate(new OkHttp3ClientHttpRequestFactory());
    }

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

启动测试：我们访问：http://localhost:8080/consume?ids=6,7,8

分析：

- user-service-demo：一个提供根据id查询用户的微服务
- consumer-demo：一个服务调用者，通过RestTemplate远程调用user-service-demo

 存在的问题 ：

- 服务管理
  - 如何自动注册和发现
  - 如何实现状态监管
  - 如何实现动态路由
- 服务如何实现负载均衡
- 服务如何解决容灾问题
- 服务如何实现统一配置