II第二章：（3）微服务案例

一、前提

约定 > 配置 > 编码

二、IDEA新建project工作空间

1、微服务cloud整体聚合父工程Project

创建父工程步骤：

（1）New Project

（2）聚合总父工程名字

（3）Maven选版本

（4）工程名字

（5）字符编码

（6）注解生效激活

（7）Java编译版本选JDK8

（8）File Type 过滤

2、父工程POM

<?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>com.njf.springcloud</groupId>
    <artifactId>cloud2020</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>
 
    <!-- 统一管理jar包版本 -->
    <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>
        <log4j.version>1.2.17</log4j.version>
        <lombok.version>1.16.18</lombok.version>
        <mysql.version>5.1.47</mysql.version>
        <druid.version>1.1.16</druid.version>
        <mybatis.spring.boot.version>1.3.0</mybatis.spring.boot.version>
    </properties>
 
    <!-- 子模块继承之后，提供作用：锁定版本+子modlue不用写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>2.1.0.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql.version}</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>${druid.version}</version>
            </dependency>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>${mybatis.spring.boot.version}</version>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>${junit.version}</version>
            </dependency>
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>${log4j.version}</version>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.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>

</project>

3、Maven 细节复习

（1）Maven中的DependencyManagement和Dependencies

dependencyManagement

Maven 使用dependencyManagement 元素来提供了一种管理依赖版本号的方式。 通常会在一个组织或者项目的最顶层的父POM 中看到dependencyManagement 元素。

使用pom.xml 中的dependencyManagement 元素能让所有在子项目中引用一个依赖而不用显式的列出版本号。

Maven 会沿着父子层次向上走，直到找到一个拥有dependencyManagement 元素的项目，然后它就会使用这个dependencyManagement 元素中指定的版本号。

这样做的好处就是：如果有多个子项目都引用同一样依赖，则可以避免在每个使用的子项目里都声明一个版本号，这样当想升级或切换到另一个版本时，只需要在顶层父容器里更新，而不需要一个一个子项目的修改 ；另外如果某个子项目需要另外的一个版本，只需要声明version就可。

• dependencyManagement里只是声明依赖，并不实现引入，因此子项目需要显示的声明需要用的依赖。

• 如果不在子项目中声明依赖，是不会从父项目中继承下来的；只有在子项目中写了该依赖项，并且没有指定具体版本，才会从父项目中继承该项，并且version和scope都读取自父pom;

• 如果子项目中指定了版本号，那么会使用子项目中指定的jar版本。

（2）maven中跳过单元测试

配置方式：

<build><!-- maven中跳过单元测试 -->
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            <configuration>
                <skip>true</skip>
            </configuration>
        </plugin>
    </plugins>
</build>

IDEA工具支持(推荐)

4、安装父工程

父工程创建完成执行mvn:install将父工程发布到仓库方便子工程继承

5、mysql驱动说明

com.mysql.jdbc.Driver和mysql-connector-java 5一起用。

com.mysql.cj.jdbc.Driver和mysql-connector-java 6 一起用。

com.mysql.cj.jdbc.Driver是mysql-connector-java 6 中的特性，相比mysql-connector-java 5 多了一个时区：serverTimezone，把数据源配置的驱动改一下就好了

org.gjt.mm.mysql.Driver是当时最好的MySQL JDBC，但不是MySQL公司的，然后MySQL将MM的JDBC驱动 收为官方的JDBC驱动，所以将驱动的package也改了，但还保留了org.gjt.mm.mysql.Driver这个路径的引用，也就是你使用新版的JDBC驱动时还可以通过这个来引用，打开下载的新版JDBC驱动的jar文件可以看到，只有一个文件的目录是org.gjt.mm.mysql，就是为了兼容而设计的。

三、Rest微服务工程构建

1、服务提供者

cloud-provider-payment8001 微服务提供者支付Module模块 （1）建cloud-provider-payment8001

（2）改 POM

<?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>cloud2020</artifactId>
        <groupId>com.njf.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-provider-payment8001</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <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>
            <version>1.1.10</version>
        </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>
        <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>

</project>

（3）写YML

server:
  port: 8001

spring:
  application:
    name: cloud-payment-service
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource            # 当前数据源操作类型
    driver-class-name: org.gjt.mm.mysql.Driver              # mysql驱动包 com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3308/cloud2020?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: root


mybatis:
  mapperLocations: classpath:mapper/*.xml
  type-aliases-package: com.njf.springcloud.entities    # 所有Entity别名类所在包

（4）主启动

@SpringBootApplication
public class PaymentMain8001 {
    public static void main(String[] args) {
        SpringApplication.run(PaymentMain8001.class, args);
    }
}

（5）业务类

① 建表 SQL

CREATE TABLE `payment` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT 'ID',
  `serial` varchar(200) DEFAULT '',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8

② entities

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Payment implements Serializable {
    private Long id;
    private String serial;
}

③ vo Json封装体CommonResult

@Data
@AllArgsConstructor
@NoArgsConstructor
public class CommonResult<T> {
    private Integer code;
    private String  message;
    private T data;

    public CommonResult(Integer code, String message) {
        this(code,message,null);
    }

}

④ dao 接口PaymentDao

@Mapper
public interface PaymentDao {
    public int create(Payment payment);

    public Payment getPaymentById(@Param("id") Long id);

}

mybaits的映射文件PaymentMapper.xml 存放路径：src\main\resources\mapper\PaymentMapper.xml

PaymentMapper.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.njf.springcloud.repository.PaymentDao">

    <resultMap id="BaseResultMap" type="com.njf.springcloud.entities.Payment">
        <id column="id" property="id" jdbcType="BIGINT"/>
        <result column="serial" property="serial" jdbcType="VARCHAR"/>
    </resultMap>

    <insert id="create" parameterType="Payment" useGeneratedKeys="true" keyProperty="id">
        INSERT INTO payment(SERIAL) VALUES(#{serial});
    </insert>

    <select id="getPaymentById" parameterType="Long" resultMap="BaseResultMap" >
        SELECT * FROM payment WHERE id=#{id};
    </select>
</mapper>

⑤ service 接口PaymentService

public interface PaymentService {
    public int create(Payment payment);

    public Payment getPaymentById(Long id);
}

实现类：

@Service
public class PaymentServiceImpl implements PaymentService {
    @Resource
    private PaymentDao paymentDao;


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

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

⑤ controller

@RestController
@Slf4j
public class PaymentController {

    @Resource
    private PaymentService paymentService;

    @PostMapping(value = "/payment/create")
    public CommonResult create(@RequestBody Payment payment) {
        int result = paymentService.create(payment);
        log.info("*****插入操作返回结果:" + result);

        if(result > 0) {
            return new CommonResult(200,"插入数据库成功",result);
        } else {
            return new CommonResult(444,"插入数据库失败",null);
        }
    }

    @GetMapping(value = "/payment/get/{id}")
    public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id) {
        Payment payment = paymentService.getPaymentById(id);
        log.info("*****查询结果:{}",payment);
        if (payment != null) {
            return new CommonResult(200,"查询成功",payment);
        }else{
            return new CommonResult(444,"没有对应记录,查询ID: "+id,null);
        }
    }
}

（6）测试

浏览器发送 get 请求：

http://localhost:8001/payment/get/1

Postman 模拟 POST请求

（7）小总结

• 建module
• 改POM
• 写YML
• 主启动
• 业务类

2、热部署Devtools

(1)Adding devtools to your project

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <scope>runtime</scope>
    <optional>true</optional>
</dependency>

(2)Adding plugin to your pom.xml

下段配置我们粘贴进聚合父类总工程的pom.xml里
 
<build>
    <finalName>你自己的工程名字</finalName>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
                <fork>true</fork>
                <addResources>true</addResources>
            </configuration>
        </plugin>
    </plugins>
</build>

(3)Enabling automatic build

(4)Update the value of

(5)重启 IDEA

3、服务消费者

cloud-consumer-order80 微服务消费者订单Module模块 (1)建cloud-consumer-order80

(2)改 POM

<?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>cloud2020</artifactId>
        <groupId>com.njf.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-consumer-order80</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

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

(3)写YML

server:
  port: 70

(4)主启动

@SpringBootApplication
public class OrderMainApp80 {
    public static void main(String[] args) {
        SpringApplication.run(OrderMainApp80.class, args);
    }

(5)业务类 ① 使用上一个工程的 entities 和 vo 包中的实体类

② RestTemplate

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/5.2.2.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。

③ config配置类

@Configuration
public class ApplicationContextConfig {

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

④ controller

@RestController
public class OrderController {

    public static final String PAYMENT_URL = "http://127.0.0.1:8001";

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping(value = "/consumer/payment/create") //客户端用浏览器是get请求，但是底层实质发送post调用服务端8001
    public CommonResult create(Payment payment) {
        return restTemplate.postForObject(PAYMENT_URL + "/payment/create", payment, CommonResult.class);
    }

    @GetMapping(value = "/consumer/payment/get/{id}")
    public CommonResult get(@PathVariable("id") Long id) {
        return restTemplate.getForObject(PAYMENT_URL + "/payment/get/" + id, CommonResult.class, id);
    }
}

(6)测试 浏览器发送 GET 请求：

http://localhost/consumer/payment/get/1

不要忘记@RequestBody注解!

4、工程重构

(1)观察问题，系统中有重复部分，重构

(2)新建 cloud-api-commons (3)POM

<?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>cloud2020</artifactId>
        <groupId>com.njf.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-api-commons</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <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>

</project>

(4)把 entities和vo包移动到该模块中

(5)maven 命令 clean install

(6)订单80和支付8001分别改造，删除各自的原先有过的entities文件夹，再加入 cloud-api-commons 模块

        <dependency>
            <groupId>com.njf.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

5、工程样图