SpringCloud(1)--入门篇-版本、环境搭建

阿航同学

已于 2022-08-15 14:24:31 修改

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于 2022-08-15 13:56:12 首次发布

本文链接：https://blog.youkuaiyun.com/qq_44148299/article/details/126331072

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SpringCloud 入门

1. 版本选择

2.SpringCloud升级导致的“升级危机”

SpringCloud 入门

文章以尚硅谷2020年发布的Springcloud+Spring Alibab为基础，记录下在学习中遇到的问题和学习心得.

1. 版本选择

官网查看SpringCloud和SpringBoot之间版本的对应关系

https://spring.io/projects/spring-cloud#overview

2.SpringCloud升级导致的“升级危机”

一、初始环境搭建

本人的环境使用：

JDK 1.8.251（使用1.8版本即可）

mysql：8.0.18

maven：3.8.3

使用idea创建maven 项目，命名为cloud2020 组名为com.atguigu.springcloud,不要使用idea自带的maven

父工程的pom依赖配置：

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <junit.version>4.12</junit.version>
    <lombok.version>1.18.10</lombok.version>
    <log4j.version>1.2.17</log4j.version>
    <mysql.version>8.0.18</mysql.version>
    <druid.version>1.1.16</druid.version>
    <mybatis.spring.boot.version>2.1.0</mybatis.spring.boot.version>
  </properties>
  <!--子模块继承之后，提供作用：锁定版本+子module不用再写groupId和version-->
  <dependencyManagement>
    <dependencies>
      <!--spring boot 2.2.2-->
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-dependencies</artifactId>
        <version>2.2.2.RELEASE</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
      <!--spring cloud Hoxton.SR1-->
      <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-dependencies</artifactId>
        <version>Hoxton.SR1</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
      <!--spring cloud alibaba 2.1.0.RELEASE-->
      <dependency>
        <groupId>com.alibaba.cloud</groupId>
        <artifactId>spring-cloud-alibaba-dependencies</artifactId>
        <version>2.2.0.RELEASE</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
      <!-- MySql -->
      <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>${mysql.version}</version>
      </dependency>
      <!-- Druid -->
      <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>${druid.version}</version>
      </dependency>
      <!-- mybatis-springboot整合 -->
      <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>${mybatis.spring.boot.version}</version>
      </dependency>
      <!--lombok-->
      <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>${lombok.version}</version>
      </dependency>
      <!--junit-->
      <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>${junit.version}</version>
      </dependency>
      <!-- log4j -->
      <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>${log4j.version}</version>
        <optional>true</optional>
      </dependency>
    </dependencies>
  </dependencyManagement>


  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
        <configuration>
          <fork>true</fork>
          <addResources>true</addResources>
        </configuration>
      </plugin>
    </plugins>
  </build>

补充：

1.dependencyManagement
dependencyManagement 只是声明依赖，并不实现引入，子项目如果不声明依赖，则不会从父项目中继承下来，如果声明但未设置version，则会从父工程的pom中继承版本（类似于java中的子类继承父类）

2.跳过单元测试

点击闪电按钮会跳过单元测试

3.mvn:install

也可点击父工程maven中的install将父类发布到仓库中

二、创建支付模块（子模块）

建module 改pom 写yml 主启动业务类

1.修改pom

在父工程名字处右键创建新的modlue命名为 cloud-provider-payment8001

在子模块cloud-provider-payment8001中修改pom文件，引入在父类中声明的依赖，

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--监控-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <!--如果没写版本,从父层面找,找到了就直接用,全局统一-->
        </dependency>
        <!--mysql-connector-java-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!--jdbc-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <!--热部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

若在子模块的maven刷新后出现 couldn`t reslove druid.version 或者${mabatis.spring.boot.version}，只需要在父pom下删除对应的dependcy下的version重新输入${druid.version}或${mabatis.spring.boot.version}即可

2.配置application.yml

Springboot配置项可以为properties，但官方推荐使用applicaiton.yml,两者都可以使Springboot成功启动

在子模块的src/main/resource下创建application.yml，若没有resource文件夹则需要自己创建

application.yml代码包括

server:
  port: 8001            #配置服务端口号

spring:
  application:
    name: cloud-payment-service             #服务名
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource  #当前数据源操作
    driver-class-name: com.mysql.cj.jdbc.Driver   #JDBC
    url: jdbc:mysql://localhost:3306/cloud2020?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8
    username: root
    password: root


mybatis:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: com.atguigu.springcloud.entities

3.支付业务具体实现

1.创建数据库名为cloud2020，在其下创建表名为payment 字段为id（bigint 主键自增）和serial（varchar（255））

2. 在子模块的main/java下创建包com.atguigu.springcloud在包下创建PaymentMain8001.java文件（启动类）

@SpringBootApplication
public class PaymentMain8001 {
/**
* @date 2022/8/13 16:01
* @author ahang
* @return void
*/
    public static void main(String[] args) {

        SpringApplication.run(PaymentMain8001.class,args);
    }
}

3.在com.atguigu.springcloud包下创建dao、controller、entities、service文件夹

在entities下创建实体类Payment和返回结果类CommentResult

@Data
@AllArgsConstructor//构造函数
@NoArgsConstructor
public class Payment implements Serializable {
    private  long id;
    private String serial;
}

@Data
@AllArgsConstructor//构造函数
@NoArgsConstructor
public class CommentResult<T> {
    private Integer code;
    private String message;
    private T data;
    public CommentResult(Integer code,String message){
        this(code,message,null);
    }
}

在dao下创建PaymentDao

@Mapper
public interface PaymentDao {

    public int create(Payment payment);
    public Payment getPaymentById(@Param("id") Long id );
}

在service下创建PaymentService和impl.PaymentServiceImpl

public interface PaymentService {
    public int create(Payment payment);
    public Payment getPaymentById(@Param("id")Long id );
}

@Service
public class PaymentServiceImpl implements PaymentService {

    @Resource
    private PaymentDao paymentDao;

    public int create(Payment payment) {
        return paymentDao.create(payment);
    }

    public Payment getPaymentById(Long id) {
        return paymentDao.getPaymentById(id);
    }
}

在controller下创建PaymentController

@RestController
@Slf4j
public class PaymentController {

    @Resource
    private PaymentService paymentService;

    @PostMapping(value = "/payment/create")
    public CommentResult create(Payment payment){
        int result=paymentService.create(payment);
        log.info("*********插入成功"+result);
        if (result>0){
            return  new CommentResult(200,"插入数据成功",result);
        }else{
            return  new CommentResult(444,"插入数据失败",null);

        }

    }

    @GetMapping(value = "/payment/get/{id}")
    public CommentResult getPaymentById(@PathVariable("id")Long id){
        Payment payment=paymentService.getPaymentById(id);

        if (payment!=null){
            log.info("*********查询结果"+payment);
            return  new CommentResult(200,"查询成功",payment);
        }else{
            return  new CommentResult(444,"没有对应记录id:"+id,null);
        }

    }
}

4.测试所写业务

启动PaymentMain8001，在数据库中插入测试数据后，在浏览器输入localhost:8001/payment/get/1

若出现如下情况：

1.启动报错:java无效源问题,这是jdk环境不搭配照成，本地JDK为1.8.xx后在idea中点击file->setting->Build,Execution,Deployment->Compiler->Java Complier下将父和子工程全设置为8

并且在file->ProjectStructure->Project->ProjectSdk设置为本地环境的1.8.xx project language level设置为8-Lanvdas,type annotations etc. 在file->ProjectStructure->Project->Modules下将父子项目的Sources同样设置为8-Lanvdas,type annotations etc.

2.若成功启动SpringBoot但在网页输入网址后网页结果为Whitelabel Error Page

一般为启动类位置不对，PaymentMain8001（启动类）应放在与 dao、service等同级目录下。若启动类位置没问题，则是在Controller类中的注解@RestController出现问题

3.因为浏览器通常不支持post请求，所以在浏览器中调用controller下的localhost:8001/payment/create?serial=ahang,会返回报错，若想测试可使用Postman工具Download Postman | Get Started for Free

三、创建消费者模块

1.创建cloud-consumer-order80子模块

2.创建启动类

3.在application.yml中写入

server:
    port:80

4.复制payment8001下的entities包

5.在容器中注册restTemplate

在com.atguigu.springcloud下创建config.ApplicationContextConfig类

@Configuration
public class ApplicationContextConfig {

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

6.编写controller.OrderController类

@RestController
@Slf4j
public class OrderController {
    public static  final  String PAYMENT_URL="http://localhost:8001";

    @Resource
    private RestTemplate restTemplate;

    @GetMapping(value = "consumer/payment/create")
    public CommentResult<Payment> creat(Payment payment){
        //restTemplate (url(请求地址),requestMap(请求参数),ResponseBean.class(HTTP响应转换被装换成的对象类型))
        return restTemplate.postForObject(PAYMENT_URL+"/payment/create",payment,CommentResult.class);
    }
    @GetMapping(value = "consumer/payment/get/{id}")
    public CommentResult<Payment> getPayment(@PathVariable("id")Long id){

        return restTemplate.getForObject(PAYMENT_URL+"/payment/get/"+id,CommentResult.class);
    }
}

7.测试所写业务

在同时打开payment8001和order80启动类后再浏览器输入localhost/consumer/payment/get/1和localhost/consumer/payment/create?serial=ahang 注意再测试后者时需要在PaymentController中的create方法添加@RequestBody，不然会导致在浏览器中显示插入成功，在数据库中插入为空的情况

四、代码重构

为了使后续代码减少冗余，将公共复用强的代码提取到一个新的子模块下命名为cloud-api-commons

修改新的子模块的pom

<dependencies>
    <!--热部署-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>cn.hutool</groupId>
        <artifactId>hutool-all</artifactId>
        <version>5.1.0</version>
    </dependency>
</dependencies>

将payment8001或者order80下的entities包复制到commons子模块的com.atguigu.springcloud下并删除payment8001和order80下的entities下的实体类

选中commons子模块使用maven的clean和install命令将commons打包发布到本地厂库，

再在payment8001和order80的pom文件中添加

<dependency>
            <groupId>com.atguigu.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>${project.version}</version>
       </dependency>

刷新maven厂库并且导包后爆红消失，启动两个子模块的启动类进行测试查询和插入（同上节）