二、SpringCloud——Demo(Consumer消費者（Client）通過REST調用Provider提供者（Server）)

1 總體介紹
Maven的分包分模塊架構

一個簡單的Maven模塊結構是這樣的：一個Project帶着多個Module子模塊MicroServiceCloud父工程（Project）下初次帶着3個子模塊（Module）

microservicecloud-api：封裝的整體Entity/接口/公共配置等
microservicecloud-provider-dept-8001：微服務落地的服務提供者
microservicecloud-consumer-dept-80：微服務調用的客戶端使用
（80端口是爲HTTP(HyperText Transport Protocol)即超文本傳輸協議開放的此爲上網衝浪使用次數最多的協議，主要用於WWW(World Wide Web)即萬維網傳輸信息的協議。
可以通過HTTP地址(即常說的"網址")加":80"來訪問網站，因爲瀏覽網頁服務默認的端口號都是80，因此只需輸入網址即可，不用輸入":80"了）

---- app-parent 一個父項目(app-parent)聚合很多子項目(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實現
1）新建 maven父工程 micro-service-springcloud,切記是Packageing是pom模式
主要是定義POM文件，將後續各個子模塊公用的jar包等統一提出來，類似一個抽象父類

編寫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 爲jar（默認）

a）編寫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><!-- 子類裏面顯示聲明纔能有明確的繼承表現，無意外就是父類的默認版本否則自己定義 -->
   <groupId>com.atguigu.springcloud</groupId>
   <artifactId>microservicecloud</artifactId>
   <version>0.0.1-SNAPSHOT</version>
  </parent>

  <artifactId>microservicecloud-api</artifactId><!-- 當前Module我自己叫什麼名字 -->

  <dependencies><!-- 當前Module需要用到的jar包，按自己需求添加，如果父類已經包含了，可以不用寫版本號 -->
   <dependency>
     <groupId>org.projectlombok</groupId>
     <artifactId>lombok</artifactId>
   </dependency>
  </dependencies>
</project>

b) 新建部門Entity且配合lombok使用

@SuppressWarnings("serial")
@NoArgsConstructor
@Data
@Accessors(chain=true)
public class Dept implements Serializable //必須序列化
{
  private Long  deptno;   //主鍵
  private String  dname;   //部門名稱
  private String  db_source;//來自那個數據庫，因爲微服務架構可以一個服務對應一個數據庫，同一個信息被存儲到不同數據庫
  
  public Dept(String dname)
  {
   super();
   this.dname = dname;
  }
}

c) mvn clean install(安裝對應的jar包到本地庫)後給其它模塊引用，達到通用目的。也即需要用到部門實體的話，不用每個工程都定義一份，直接引用本模塊即可。

3）新建microservicecloud-provider-8001 部門微服務提供者maven Module

a)編寫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><!-- 引入自己定義的api通用包，可以使用Dept部門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>
   <!-- 修改後立即生效，熱部署 -->
   <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路徑下新建application.properties,並編輯如下內容，注意註釋另啓一行寫，value值結尾不要有空格

server.port=8001
#mybatis配置文件所在路徑
mybatis.config-location=classpath:mybatis/mybatis.cfg.xml
# 所有Entity別名類所在包
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
# 當前數據源操作類型
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
# mysql驅動包
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
# 數據庫名稱
spring.datasource.url=jdbc:mysql://localhost:3306/cloudDB01
spring.datasource.username=root
spring.datasource.password=123456
# 數據庫連接池的最小維持連接數
spring.datasource.dbcp2.min-idle=5                                           
# 初始化連接數
spring.datasource.dbcp2.initial-size=5                                      
# 最大連接數
spring.datasource.dbcp2.max-total=5
# 等待連接獲取的最大超時時間
spring.datasource.dbcp2.max-wait-millis=200

c) 工程src/main/resources目錄下新建mybatis文件夾後新建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"/><!-- 二級緩存開啓 -->
  </settings>

</configuration>

d)MySQL創建部門數據庫腳本（DATABASE()函數獲取當前數據庫名稱）

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('開發部',DATABASE());
INSERT INTO dept(dname,db_source) VALUES('人事部',DATABASE());
INSERT INTO dept(dname,db_source) VALUES('財務部',DATABASE());
INSERT INTO dept(dname,db_source) VALUES('市場部',DATABASE());
INSERT INTO dept(dname,db_source) VALUES('運維部',DATABASE());
 
SELECT * FROM dept;

e) 編寫 DeptDao部門接口

@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目錄下新建mapper文件夾後再建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部門服務接口

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

h) DeptServiceImpl部門服務接口實現類

@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部門微服務提供者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主啓動類DeptProvider8001

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

k)測試
http://localhost:8001/dept/get/2

http://localhost:8001/dept/list

l) 最終工程展現

4）新建 microservicecloud-consumer-80 部門微服務消費者maven Module

a)編寫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>部門微服務消費者</description>

  <dependencies>
   <dependency><!-- 自己定義的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>
   <!-- 修改後立即生效，熱部署 -->
   <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)編寫 com.tang.springcloud.config包下ConfigBean的編寫（類似spring裏面的applicationContext.xml寫入的注入Bean）

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

d) com.atguigu.tang.controller包下新建DeptConsumerController部門微服務消費者REST

RestTemplate提供了多種便捷訪問遠程Http服務的方法， 是一種簡單便捷的訪問restful服務模板類，是Spring提供的用於訪問Rest服務的客戶端模板工具集

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

使用
使用restTemplate訪問restful接口非常的簡單粗暴無腦。(url, requestMap, ResponseBean.class)這三個參數分別代表 REST請求地址、請求參數、HTTP響應轉換被轉換成的對象類型。

@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主啓動類

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

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