Jeecg-Cloud学习之路（一）

首先，Spring-Cloud目前是行业的潮流，貌似不会就落后了，笔者为了不脱离大部队只能深入学习一下了。

其次、跳槽到一家公司，给公司推荐了Jeecg-Boot的开发平台，那么为了后面扩展为cloud也需要学习了。

废话不多说，跟着Jeecg团队出品的视频学习，发现没有给源代码，搞开发这一行眼过千遍不如手过一遍，还是跟着视频敲一遍，为了方便大家把源码贴在下面

Jeecg-CloudB站视频地址（V2.2.0）：https://www.bilibili.com/video/BV1pV411r7xW

nacos下载地址（V1.2.1）：https://pan.baidu.com/s/1XtAguW4JNrwuGF-U3SNSeQ 　　　　提取码：z7d9

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首先新建一个Maven项目，jeecg-cloud，父项目的pom.xml文件如下面代码所示：

 <?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>jeecg-cloud</groupId>
     <artifactId>jeecg-cloud</artifactId>
     <version>1.0-SNAPSHOT</version>
     <modules>
         <module>jeecg-provider</module>
         <module>jeecg-config</module>
         <module>jeecg-gateway</module>
         <module>jeecg-feign</module>
     </modules>

     <packaging>pom</packaging>

     <dependencyManagement>
         <dependencies>
             <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-dependencies -->
             <dependency>
                 <groupId>org.springframework.cloud</groupId>
                 <artifactId>spring-cloud-dependencies</artifactId>
                 <version>Hoxton.SR7</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

             <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-dependencies -->
             <dependency>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-dependencies</artifactId>
                 <version>2.3.3.RELEASE</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

             <dependency>
                 <groupId>com.alibaba.cloud</groupId>
                 <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                 <version>2.2.1.RELEASE</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>

         </dependencies>
     </dependencyManagement>

     <build>
         <plugins>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <configuration>
                     <source>1.8</source>
                     <target>1.8</target>
                     <encoding>UTF-8</encoding>
                 </configuration>
             </plugin>
         </plugins>

         <resources>
             <resource>
                 <directory>src/main/resources</directory>
                 <filtering>true</filtering>
             </resource>
         </resources>
     </build>

 </project>

之后新建一个jeecg-provider模块（具体步骤参见视频，我这里只是把他们的PPT上面的依赖、配置、代码写下来）：

pom.xml（jeecg-provider）文件：

<?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>jeecg-cloud</artifactId>
        <groupId>jeecg-cloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>jeecg-provider</artifactId>

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

        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>

        <!--服务降级、熔断-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>
    </dependencies>
</project>

application.yml：

server:
  port: 8082
spring:
  application:
    name: jeecg-provider
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848

ProviderApplication.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

/**
 * @author zx
 */
@SpringBootApplication
@EnableDiscoveryClient
@EnableCircuitBreaker
public class ProviderApplication {

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

TestController.java

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty;
import org.springframework.beans.factory.annotation.Value;
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 zx
 */
@RestController
@RequestMapping("/test")
public class TestController {

    @Value("${server.port}")
    private String serverPort;

    @RequestMapping("/one")
    public String one(){
        return "my port is: "+serverPort;
    }

    @RequestMapping("/showName/{name}")
    public String showName(@PathVariable("name") String name){

        try {
            Thread.sleep(4000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "your name is : " + name;
    }

    @HystrixCommand(fallbackMethod = "hystrixDefault",commandProperties = {
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value = "3000")})
    @RequestMapping("/hystrixTest/{name}")
    public String hystrixTest(@PathVariable("name") String name) {
        try {
            Thread.sleep(4000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "我是正常的返回" + name;
    }

    private String hystrixDefault(String  name){
        return "程序超市 " + name;
    }

    @HystrixCommand(fallbackMethod = "netFallback",commandProperties = {
            @HystrixProperty(name = "circuitBreaker.enabled",value = "true"),
            @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold",value = "10"),
            @HystrixProperty(name = "circuitBreaker.errorThresholdPercentage",value = "60"),
            @HystrixProperty(name = "circuitBreaker.sleepWindowInMilliseconds",value = "5000"),})
    @GetMapping("/net/{age}")
    public String net(@PathVariable("age") int age){
        if (age < 18){
            throw new RuntimeException();
        }
        return "正在上网，年龄 " +age;
    }

    public String netFallback(@PathVariable("age") int age){
        return "未成年，不允许进入网吧，年龄 " +age;
    }
}

其他模块请看下一篇，就不要搞得篇幅太长了。