创建父Maven工程

首先我们创建一个Maven项目

我们把此项目当做我们项目的父项目，以后我们所有的子项目都应该继承这个项目，来看一下此项目的pom.xml文件都是依赖了什么

<?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>cn.org.zhixiang</groupId>
    <artifactId>spring-cloud-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>pom</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
    </parent>

    <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>Finchley.RELEASE</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
    </dependencyManagement>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

</project>

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>cn.org.zhixiang</groupId>
    <artifactId>spring-cloud-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>pom</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
    </parent>

    <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>Finchley.RELEASE</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
    </dependencyManagement>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

</project>

创建服务提供者

右键项目名称：spring-cloud-demo，选择New-->Module,选择Maven，然后点击next，然后呢artifactId给项目取名为cloud-demo-provider，现在服务提供者项目就创建好了。因为接下来我们测试需要访问程序，所以接着我们引入所需的web依赖。

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

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

2.在resources文件夹下新建application.properties或者application.yml（二者任选其一），添加如下配置:

properties文件这样写

spring.application.name=provider-demo
server.port=8078
name=provider-demo
server.port=8078

yml这样写

spring:
  application:
    name: provider-demo
server:
  port: 8078

  application:
    name: provider-demo
server:
  port: 8078

spring.application.name呢，意思是给给项目起个名字叫做provider-demo

server.port呢，指定项目启动时的端口为8078

3.在Java文件夹下创建包cn.org.zhixiang（这个包名是我的网站域名的反转，大家可以自行定义）,在此包下新建CloudDemoProviderApplication类

package cn.org.zhixiang;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class CloudDemoProviderApplication {

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

 cn.org.zhixiang;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class CloudDemoProviderApplication {

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

@SpringBootApplication注解呢是SpringBoot的一个组合注解，主要注解为@Configuration、@EnableAutoConfiguration、@ComponentScan

我们使用SpringBoot启动项目时一般都会使用此注解，一会启动项目的时候我们在这个类中右键选择run CloudDemoProviderApplication 就可以启动了

4.在cn.org.zhxiang包下新建包domain,在domain包中创建一个User实体类

public class User{

    private long id;
    private String name;
    private int age;
    public long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}
 class User{

    private long id;
    private String name;
    private int age;
    public long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

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

5.在cn.org.zhxiang包下新建包controller,在controller包中创建一个类UserController

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

    @GetMapping(value = "/getUser/{id}")
    public User getUser(@PathVariable Long id){
        User user=new User();
        user.setId(id);
        user.setName("张三");
        user.setAge(18);
        return user;
    }
    @GetMapping(value = "/getName")
    public String getName(){
        return "张三";
    }
}

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

    @GetMapping(value = "/getUser/{id}")
    public User getUser(@PathVariable Long id){
        User user=new User();
        user.setId(id);
        user.setName("张三");
        user.setAge(18);
        return user;
    }
    @GetMapping(value = "/getName")
    public String getName(){
        return "张三";
    }
}

@RestController注解呢，其实就是@ResponseBody ＋ @Controller的组合注解，@GetMapping呢，相当于@RequestMapping(value="", method = RequestMethod.GET)

现在我们这个Provider的项目的目录结构应该是这样的：

6.安装刚才所说的启动项目，打开浏览器访问http://localhost:8078/user/getUser/3 。如果浏览器返回一个json {"id":3,"name":"张三","age":18}，那么就代表我们的服务提供者写好了。

创建服务消费者

1.同服务提供者的套路，我们创建一个名为cloud-demo-consumer的工程，他也只需要依赖web模块，在application.properties或者application.yml配置端口为8088，应用名称为consumer-demo。

2.创建cn.org.zhixiang包，创建CloudDemoConsumerApplication类。不同于提供者的是，这次启动类中需要增加一段代码

@SpringBootApplication
public class CloudDemoConsumerApplication {
   @Bean
   public RestTemplate restTemplate(){
      return new RestTemplate();
   }
   public static void main(String[] args) {
      SpringApplication.run(CloudDemoConsumerApplication.class, args);
   }
}

public class CloudDemoConsumerApplication {
   @Bean
   public RestTemplate restTemplate(){
      return new RestTemplate();
   }
   public static void main(String[] args) {
      SpringApplication.run(CloudDemoConsumerApplication.class, args);
   }
}

RestTemplate类呢，是一个对于HTTP请求封装的一个类，相信大家都知道我们使用原生API访问一个URL需要的代码是很多的，这个呢，就是一个封装简化的版本。

@Bean注解呢，其实就等同于以前在xml中配置的如下代码

<beans>
<bean id="restTemplate" class="org.springframework.web.client.RestTemplate"/>
</beans>
beans>
<bean id="restTemplate" class="org.springframework.web.client.RestTemplate"/>
</beans>

同样的，在此项目中增加一个User类，与提供者一样。

而UserController就不一样了

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

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/getUser/{id}")
    public User getUser(@PathVariable Long id){
        return restTemplate.getForObject("http://localhost:8078/user/getUser/"+id,User.class);
    }
}

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

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/getUser/{id}")
    public User getUser(@PathVariable Long id){
        return restTemplate.getForObject("http://localhost:8078/user/getUser/"+id,User.class);
    }
}