初识SpringCloud

后端码匠

发布于 2020-09-15 15:10:48

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发布于 2020-09-15 15:10:48

Spring Cloud 是一套完整的微服务解决方案，基于 Spring Boot 框架，准确的说，它不是一个框架，而是一个大的容器，它将市面上较好的微服务框架集成进来，从而简化了开发者的代码量。

Spring Cloud 是什么？

Spring Cloud 是一系列框架的有序集合，它利用 Spring Boot 的开发便利性简化了分布式系统的开发，比如服务发现、服务网关、服务路由、链路追踪等。Spring Cloud 并不重复造轮子，而是将市面上开发得比较好的模块集成进去，进行封装，从而减少了各模块的开发成本。换句话说：Spring Cloud 提供了构建分布式系统所需的“全家桶”。

Spring Cloud 现状

目前，国内使用 Spring Cloud 技术的公司并不多见，不是因为 Spring Cloud 不好，主要原因有以下几点：

Spring Cloud 中文文档较少，出现问题网上没有太多的解决方案。
国内创业型公司技术老大大多是阿里系员工，而阿里系多采用 Dubbo 来构建微服务架构。
大型公司基本都有自己的分布式解决方案，而中小型公司的架构很多用不上微服务，所以没有采用 Spring Cloud 的必要性。

但是，微服务架构是一个趋势，而 Spring Cloud 是微服务解决方案的佼佼者.

Spring Cloud 优缺点

优点

集大成者，Spring Cloud 包含了微服务架构的方方面面。
约定优于配置，基于注解，没有配置文件。
轻量级组件，Spring Cloud 整合的组件大多比较轻量级，且都是各自领域的佼佼者。
开发简便，Spring Cloud 对各个组件进行了大量的封装，从而简化了开发。
开发灵活，Spring Cloud 的组件都是解耦的，开发人员可以灵活按需选择组件。

缺点

项目结构复杂，每一个组件或者每一个服务都需要创建一个项目。
部署门槛高，项目部署需要配合 Docker 等容器技术进行集群部署，而要想深入了解 Docker，学习成本高。

Spring Cloud 的优势是显而易见的。学习 Spring Cloud 是一个不错的选择。

Spring Cloud 和 Dubbo 对比

Dubbo 只是实现了服务治理，而 Spring Cloud 实现了微服务架构的方方面面，服务治理只是其中的一个方面。下面通过一张图对其进行比较：

可以看出，Spring Cloud 比较全面，而 Dubbo 由于只实现了服务治理，需要集成其他模块，需要单独引入，增加了学习成本和集成成本。

项目结构

父项目pom

<?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>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>cn.com.codingce</groupId>
    <artifactId>springcloud</artifactId>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>springcloud-api</module>
        <module>springcloud-provider-dept</module>
        <module>springcloud-consumer-dept</module>
    </modules>

    <!--打包方式-->
    <packaging>pom</packaging>

    <!--统一配置 版本号-->
    <properties>
        <junit.version>4.12</junit.version>
        <lombok.version>1.16.10</lombok.version>
        <mysql.version>8.0.11</mysql.version>
        <druid.version>1.1.10</druid.version>
        <logbackcore.version>1.2.3</logbackcore.version>
    </properties>

    <dependencyManagement>
        <dependencies>

            <!-- springcloud的依赖 -->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Greenwich.SR1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <!--springboot依赖-->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <scope>2.1.4.RELEASE</scope>
            </dependency>

            <!--连接数据库-->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql.version}</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>${druid.version}</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter -->
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.2</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/ch.qos.logback/logback-core -->
            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-core</artifactId>
                <version>1.2.3</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/junit/junit -->
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>${junit.version}</version>
            </dependency>

            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
                <version>2.2.2.RELEASE</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-jetty -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-jetty</artifactId>
                <version>2.0.1.RELEASE</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
                <version>2.0.1.RELEASE</version>
            </dependency>

            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
                <version>2.1.4.RELEASE</version>
            </dependency>

        </dependencies>
    </dependencyManagement>


</project>

实体类

pom

<?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</artifactId>
        <groupId>cn.com.codingce</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-api</artifactId>

    <dependencies>
        <!--当前module自己需要的依赖, 如果父依赖中已经配置了版本-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <!--junit-->
<!--        <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>

    </dependencies>
</project>

Dept

package cn.com.codingce.pojo;

import lombok.experimental.Accessors;

import java.io.Serializable;

/**
 * @author xzMa
 * Dept实体类 orm  类表关系映射
 */
@Accessors  //链式写法
public class Dept implements Serializable {
    private Long deptno;
    private String dname;
    private String db_source;

    /**
     * Dept dept = new Dept();
     * dept.setDeptNo("").setDeptyName().....  都行
     */

    public Dept() {
    }

    public Dept(Long deptno, String dname, String db_source) {
        this.deptno = deptno;
        this.dname = dname;
        this.db_source = db_source;
    }


    public Long getDeptno() {
        return deptno;
    }

    public void setDeptno(Long deptno) {
        this.deptno = deptno;
    }

    public String getDname() {
        return dname;
    }

    public void setDname(String dname) {
        this.dname = dname;
    }

    public String getDb_source() {
        return db_source;
    }

    public void setDb_source(String db_source) {
        this.db_source = db_source;
    }

    @Override
    public String toString() {
        return "Dept{" +
                "deptno=" + deptno +
                ", dname='" + dname + '\'' +
                ", db_source='" + db_source + '\'' +
                '}';
    }
}

服务端

pom

<?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</artifactId>
        <groupId>cn.com.codingce</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-provider-dept</artifactId>

    <dependencies>
        <!--我们需要拿到实体类, 所以要配置api -module-->
        <dependency>
            <groupId>cn.com.codingce</groupId>
            <artifactId>springcloud-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

        <!--junit-->
        <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>

        <!-- https://mvnrepository.com/artifact/ch.qos.logback/logback-core -->
        <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>
        </dependency>

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

<!--        &lt;!&ndash;jetty&ndash;&gt;-->
<!--        &lt;!&ndash; https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-jetty &ndash;&gt;-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>

        <!--热部署工具-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
    </dependencies>
</project>

Controller

package cn.com.codingce.controller;

import cn.com.codingce.pojo.Dept;
import cn.com.codingce.service.DeptService;
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.PostMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.util.List;

/**
 * @author xzMa
 *
 * 提供RestFul服务
 */
@RestController
public class DeptController {

    @Resource
    private DeptService deptService;

    @PostMapping("/dept/add")
    public boolean addDept(Dept dept) {
        return deptService.addDept(dept);
    }

    @GetMapping("/dept/get/{id}")
    public Dept queryBuId(@PathVariable("id") Long id) {
        return deptService.queryById(id);
    }

    @GetMapping("/dept/list")
    public List<Dept> queryAll() {
        return deptService.queryAll();
    }

}

DAO (mapper)

package cn.com.codingce.dao;

import cn.com.codingce.pojo.Dept;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;

@Mapper
@Repository
public interface DeptDao {

    public boolean addDept(Dept dept);

    public Dept queryById(Long id);

    public List<Dept> queryAll();

}

Mapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.com.codingce.dao.DeptDao">

    <insert id="addDept" parameterType="Dept">
        insert into dept(dname, db_source) values (#{dname}, DATABASE())
    </insert>
    
    <select id="queryById" parameterType="Long" resultType="Dept">
        select * from dept where deptno = #{deptno}
    </select>

    <select id="queryAll" resultType="Dept">
        select * from dept
    </select>

</mapper>

Service接口

package cn.com.codingce.service;

import cn.com.codingce.pojo.Dept;

import java.util.List;

public interface DeptService {
    public boolean addDept(Dept dept);

    public Dept queryById(Long id);

    public List<Dept> queryAll();
}

Service实现类

package cn.com.codingce.service;

import cn.com.codingce.dao.DeptDao;
import cn.com.codingce.pojo.Dept;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;

@Service
public class DeptServiceImpl implements DeptService {

    @Resource
    private DeptDao deptDao;

    @Override
    public boolean addDept(Dept dept) {
        return deptDao.addDept(dept);
    }

    @Override
    public Dept queryById(Long id) {
        return deptDao.queryById(id);
    }

    @Override
    public List<Dept> queryAll() {
        return deptDao.queryAll();
    }
}

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<!--核心配置文件-->
<configuration>
    <!--开启二级缓存-->
    <settings>
        <setting name="cacheEnabled" value="true"/>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>
</configuration>

application.yml

server:
  port: 8001

#mybatis配置
mybatis:
  type-aliases-package: cn.com.codingce.pojo
  config-location: classpath:mybatis/mybatis-config.xml
  mapper-locations: classpath:mybatis/mapper/*.xml
#  configuration:
#    map-underscore-to-camel-case: true

# spring配置
spring:
  application:
    name: springcloud-provider-dept
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource # 数据源 德鲁伊
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://cdb-q9atzwrq.bj.tencentcdb.com:10167/db01?useSSL=true
    username: root
    password: 123456

客户端

pom

<?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</artifactId>
        <groupId>cn.com.codingce</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-consumer-dept</artifactId>

    <dependencies>
        <!--我们需要拿到实体类, 所以要配置api -module-->
        <dependency>
            <groupId>cn.com.codingce</groupId>
            <artifactId>springcloud-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

        <!--热部署工具-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>

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

配置文件

package cn.com.codingce.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
public class ConfigBean {   //configuration -- spring applicationContext.xml

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

}

Controller

package cn.com.codingce.controller;

import cn.com.codingce.pojo.Dept;
import org.springframework.beans.factory.annotation.Autowired;
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
public class DeptConsumerController {

    // 理解消费者, 不应该有service层
    //RestFul风格
    //(url, 实体: Map classs<T> responseType)

    @Autowired
    private RestTemplate restTemplate;  //提供多种便捷访问远程http服务的方法

    private static final String REST_URL_PREFIX = "http://localhost:8001";


    @RequestMapping("/consumer/dept/add")
    public boolean add(Dept dept) {
        return restTemplate.postForObject(REST_URL_PREFIX + "/dept/add", dept, Boolean.class);
    }

    //http://localhost:8001/dept/list
    @RequestMapping("/consumer/dept/get/{id}")
    public Dept get(@PathVariable("id") Long id) {
        return restTemplate.getForObject(REST_URL_PREFIX + "/dept/get/" + id, Dept.class );
    }

    @RequestMapping("/consumer/dept/list")
    public List<Dept> list() {
        return restTemplate.getForObject(REST_URL_PREFIX + "/dept/list" , List.class );
    }

}

application.yml

server:
  port: 80

项目地址:https://github.com/xzMhehe/codingce-java

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原始发表：2020-09-14，如有侵权请联系 cloudcommunity@tencent.com 删除

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