二、SpringCloud——Demo(Consumer消费者（Client）通过REST调用Provider提供者（Server）)

1 总体介绍
Maven的分包分模块架构

一个简单的Maven模块结构是这样的：一个Project带着多个Module子模块MicroServiceCloud父工程（Project）下初次带着3个子模块（Module）

microservicecloud-api：封装的整体Entity/接口/公共配置等
microservicecloud-provider-dept-8001：微服务落地的服务提供者
microservicecloud-consumer-dept-80：微服务调用的客户端使用
（80端口是为HTTP(HyperText Transport Protocol)即超文本传输协议开放的此为上网冲浪使用次数最多的协议，主要用于WWW(World Wide Web)即万维网传输信息的协议。
可以通过HTTP地址(即常说的"网址")加":80"来访问网站，因为浏览网页服务默认的端口号都是80，因此只需输入网址即可，不用输入":80"了）

---- app-parent 一个父项目(app-parent)聚合很多子项目(app-util,app-dao,app-service,app-web)
|---- pom.xml (pom)
|
|-------- app-util
| |-------- pom.xml (jar)
|
|-------- app-dao
| |-------- pom.xml (jar)
|
|-------- app-service
| |-------- pom.xml (jar)
|
|-------- app-web
|-------- pom.xml (war)

2 Demo实现
1）新建 maven父工程 micro-service-springcloud,切记是Packageing是pom模式
主要是定义POM文件，将后续各个子模块公用的jar包等统一提出来，类似一个抽象父类

编写pom.xml文件如下

<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.atguigu.springcloud</groupId>
  <artifactId>microservicecloud</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>pom</packaging>

  <properties>
   <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   <maven.compiler.source>1.8</maven.compiler.source>//使用的jdk版本
   <maven.compiler.target>1.8</maven.compiler.target>
   <junit.version>4.12</junit.version>
   <log4j.version>1.2.17</log4j.version>
   <lombok.version>1.16.18</lombok.version>
  </properties>

  <dependencyManagement>
   <dependencies>
     <dependency>
       <groupId>org.springframework.cloud</groupId>
       <artifactId>spring-cloud-dependencies</artifactId>
       <version>Dalston.SR1</version>
       <type>pom</type>
       <scope>import</scope>
     </dependency>
     <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-dependencies</artifactId>
       <version>1.5.9.RELEASE</version>
       <type>pom</type>
       <scope>import</scope>
     </dependency>
     <dependency>
       <groupId>mysql</groupId>
       <artifactId>mysql-connector-java</artifactId>
       <version>5.0.4</version>
     </dependency>
     <dependency>
       <groupId>com.alibaba</groupId>
       <artifactId>druid</artifactId>
       <version>1.0.31</version>
     </dependency>
     <dependency>
       <groupId>org.mybatis.spring.boot</groupId>
       <artifactId>mybatis-spring-boot-starter</artifactId>
       <version>1.3.0</version>
     </dependency>
     <dependency>
       <groupId>ch.qos.logback</groupId>
       <artifactId>logback-core</artifactId>
       <version>1.2.3</version>
     </dependency>
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
       <version>${junit.version}</version>
       <scope>test</scope>
     </dependency>
     <dependency>
       <groupId>log4j</groupId>
       <artifactId>log4j</artifactId>
       <version>${log4j.version}</version>
     </dependency>
   </dependencies>
  </dependencyManagement>
</project>

2）新建microservicecloud-api 子moudle maven packaging 为jar（默认）

a）编写pom.xml文件

<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><!-- 子类里面显示声明才能有明确的继承表现，无意外就是父类的默认版本否则自己定义 -->
   <groupId>com.atguigu.springcloud</groupId>
   <artifactId>microservicecloud</artifactId>
   <version>0.0.1-SNAPSHOT</version>
  </parent>

  <artifactId>microservicecloud-api</artifactId><!-- 当前Module我自己叫什么名字 -->

  <dependencies><!-- 当前Module需要用到的jar包，按自己需求添加，如果父类已经包含了，可以不用写版本号 -->
   <dependency>
     <groupId>org.projectlombok</groupId>
     <artifactId>lombok</artifactId>
   </dependency>
  </dependencies>
</project>

b) 新建部门Entity且配合lombok使用

@SuppressWarnings("serial")
@NoArgsConstructor
@Data
@Accessors(chain=true)
public class Dept implements Serializable //必须序列化
{
  private Long  deptno;   //主键
  private String  dname;   //部门名称
  private String  db_source;//来自那个数据库，因为微服务架构可以一个服务对应一个数据库，同一个信息被存储到不同数据库
  
  public Dept(String dname)
  {
   super();
   this.dname = dname;
  }
}

c) mvn clean install(安装对应的jar包到本地库)后给其它模块引用，达到通用目的。也即需要用到部门实体的话，不用每个工程都定义一份，直接引用本模块即可。

3）新建microservicecloud-provider-8001 部门微服务提供者maven Module

a)编写pom.xml如下

<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>com.atguigu.springcloud</groupId>
   <artifactId>microservicecloud</artifactId>
   <version>0.0.1-SNAPSHOT</version>
  </parent>

  <artifactId>microservicecloud-provider-dept-8001</artifactId>

  <dependencies>
   <dependency><!-- 引入自己定义的api通用包，可以使用Dept部门Entity -->
     <groupId>com.atguigu.springcloud</groupId>
     <artifactId>microservicecloud-api</artifactId>
     <version>${project.version}</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-starter-jetty</artifactId>
   </dependency>
   <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-web</artifactId>
   </dependency>
   <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-test</artifactId>
   </dependency>
   <!-- 修改后立即生效，热部署 -->
   <dependency>
     <groupId>org.springframework</groupId>
     <artifactId>springloaded</artifactId>
   </dependency>
   <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-devtools</artifactId>
   </dependency>
  </dependencies>

</project>

b) resource路径下新建application.properties,并编辑如下内容，注意注释另启一行写，value值结尾不要有空格

server.port=8001
#mybatis配置文件所在路径
mybatis.config-location=classpath:mybatis/mybatis.cfg.xml
# 所有Entity别名类所在包
mybatis.type-aliases-package=com.tang.springcloud.entity
# mapper映射文件
mybatis.mapper-locations=classpath:mybatis/mapper/**/*.xml

spring.application.name=microservicecloud-dept
# 当前数据源操作类型
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
# mysql驱动包
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
# 数据库名称
spring.datasource.url=jdbc:mysql://localhost:3306/cloudDB01
spring.datasource.username=root
spring.datasource.password=123456
# 数据库连接池的最小维持连接数
spring.datasource.dbcp2.min-idle=5                                           
# 初始化连接数
spring.datasource.dbcp2.initial-size=5                                      
# 最大连接数
spring.datasource.dbcp2.max-total=5
# 等待连接获取的最大超时时间
spring.datasource.dbcp2.max-wait-millis=200

c) 工程src/main/resources目录下新建mybatis文件夹后新建mybatis.cfg.xml文件

<?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">
  
<configuration>

  <settings>
   <setting name="cacheEnabled" value="true"/><!-- 二级缓存开启 -->
  </settings>

</configuration>

d)MySQL创建部门数据库脚本（DATABASE()函数获取当前数据库名称）

DROP DATABASE IF EXISTS cloudDB01;
CREATE DATABASE cloudDB01 CHARACTER SET UTF8;
USE cloudDB01;
CREATE TABLE dept
(
  deptno BIGINT NOT NULL PRIMARY KEY AUTO_INCREMENT,
  dname VARCHAR(60),
  db_source   VARCHAR(60)
);
 
INSERT INTO dept(dname,db_source) VALUES('开发部',DATABASE());
INSERT INTO dept(dname,db_source) VALUES('人事部',DATABASE());
INSERT INTO dept(dname,db_source) VALUES('财务部',DATABASE());
INSERT INTO dept(dname,db_source) VALUES('市场部',DATABASE());
INSERT INTO dept(dname,db_source) VALUES('运维部',DATABASE());
 
SELECT * FROM dept;

e) 编写 DeptDao部门接口

@Mapper
public interface DeptDao
{
  public boolean addDept(Dept dept);

  public Dept findById(Long id);

  public List<Dept> findAll();
}

f) 工程src/main/resources/mybatis目录下新建mapper文件夹后再建DeptMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 
<mapper namespace="com.tang.springcloud.dao.DeptDao">
 
  <select id="findById" resultType="Dept" parameterType="Long">
   select deptno,dname,db_source from dept where deptno=#{deptno}; 
  </select>
  <select id="findAll" resultType="Dept">
   select deptno,dname,db_source from dept; 
  </select>
  <insert id="addDept" parameterType="Dept">
   INSERT INTO dept(dname,db_source) VALUES(#{dname},DATABASE());
  </insert>
  
</mapper>

g) DeptService部门服务接口

public interface DeptService
{
  public boolean add(Dept dept);
  public Dept    get(Long id);
  public List<Dept> list();
}

h) DeptServiceImpl部门服务接口实现类

@Service
public class DeptServiceImpl implements DeptService
{
  @Autowired
  private DeptDao dao ;
  
  @Override
  public boolean add(Dept dept)
  {
   return dao.addDept(dept);
  }

  @Override
  public Dept get(Long id)
  {
   return dao.findById(id);
  }

  @Override
  public List<Dept> list()
  {
   return dao.findAll();
  }

}
 

i) DeptController部门微服务提供者REST

@RestController
public class DeptController
{
  @Autowired
  private DeptService service;
  
  @RequestMapping(value="/dept/add",method=RequestMethod.POST)
  public boolean add(@RequestBody Dept dept)
  {
   return service.add(dept);
  }
  
  @RequestMapping(value="/dept/get/{id}",method=RequestMethod.GET)
  public Dept get(@PathVariable("id") Long id)
  {
   return service.get(id);
  }
  
  @RequestMapping(value="/dept/list",method=RequestMethod.GET)
  public List<Dept> list()
  {
   return service.list();
  }
}
 

j ) DeptProvider8001主启动类DeptProvider8001

@SpringBootApplication
public class DeptProvider8001_App
{
  public static void main(String[] args)
  {
   SpringApplication.run(DeptProvider8001_App.class, args);
  }

k)测试
http://localhost:8001/dept/get/2

http://localhost:8001/dept/list

l) 最终工程展现

4）新建 microservicecloud-consumer-80 部门微服务消费者maven Module

a)编写pom.xml

<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>com.atguigu.springcloud</groupId>
   <artifactId>microservicecloud</artifactId>
   <version>0.0.1-SNAPSHOT</version>
  </parent>

  <artifactId>microservicecloud-consumer-dept-80</artifactId>
  <description>部门微服务消费者</description>

  <dependencies>
   <dependency><!-- 自己定义的api -->
     <groupId>com.atguigu.springcloud</groupId>
     <artifactId>microservicecloud-api</artifactId>
     <version>${project.version}</version>
   </dependency> 
   <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-web</artifactId>
   </dependency>
   <!-- 修改后立即生效，热部署 -->
   <dependency>
     <groupId>org.springframework</groupId>
     <artifactId>springloaded</artifactId>
   </dependency>
   <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-devtools</artifactId>
   </dependency>   
  </dependencies>

</project>

b) 配置文件 application.properties

server.port=80

c)编写 com.tang.springcloud.config包下ConfigBean的编写（类似spring里面的applicationContext.xml写入的注入Bean）

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

d) com.atguigu.tang.controller包下新建DeptConsumerController部门微服务消费者REST

RestTemplate提供了多种便捷访问远程Http服务的方法， 是一种简单便捷的访问restful服务模板类，是Spring提供的用于访问Rest服务的客户端模板工具集

官网地址
https://docs.spring.io/spring-framework/docs/4.3.7.RELEASE/javadoc-api/org/springframework/web/client/RestTemplate.html

使用
使用restTemplate访问restful接口非常的简单粗暴无脑。(url, requestMap, ResponseBean.class)这三个参数分别代表 REST请求地址、请求参数、HTTP响应转换被转换成的对象类型。

@RestController
public class DeptConsumerController {
    private static final String REST_URL_PREFIX = "http://localhost:8001";

    @Autowired
    private RestTemplate restTemplate;

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

    @RequestMapping(value="/consumer/dept/get/{id}")
    public Dept get(@PathVariable("id") Long id)
    {
        return restTemplate.getForObject(REST_URL_PREFIX+"/dept/get/"+id, Dept.class);
    }

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

}

e ) DeptConsumer80_App主启动类

@SpringBootApplication
public class DeptConsumer80_App
{
  public static void main(String[] args)
  {
   SpringApplication.run(DeptConsumer80_App.class, args);
  }
}

f) 测试
http://localhost/consumer/dept/get/2
http://localhost/consumer/dept/list
http://localhost/consumer/dept/add?dname=AI