【亲测】微服务场景模拟(案例)

￡神魔★判官ぃ 2022-04-12 03:12 246阅读 0赞

# 一.微服务场景模拟 #

首先，我们需要模拟一个服务调用的场景。方便后面学习微服务架构

## 1.1.服务提供者 ##

我们新建一个项目，对外提供查询用户的服务。

创建数据库

CREATE TABLE `tb_user` (
      `id` int(11) NOT NULL,
      `user_name` varchar(50) DEFAULT NULL,
      `password` varchar(50) DEFAULT NULL,
      `name` varchar(50) DEFAULT NULL,
      `age` int(11) DEFAULT NULL,
      `sex` int(11) DEFAULT NULL,
      `birthday` date DEFAULT NULL,
      `created` date DEFAULT NULL,
      `updated` date DEFAULT NULL,
      `note` varchar(50) DEFAULT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
    
    -- ----------------------------
    -- Records of tb_user
    -- ----------------------------
    INSERT INTO `tb_user` VALUES ('1', 'tom', '123456', 'tom', '20', '1', '1999-11-29', '2018-11-29', '2018-11-29', null);
    INSERT INTO `tb_user` VALUES ('2', 'lucy', '123456', 'lucy', '20', '2', '2018-11-29', '2018-11-29', '2018-11-29', null);

### 1.1.1.Spring脚手架创建工程 ###

借助于Spring提供的快速搭建工具：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70]

填写项目信息：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 1]

添加web依赖：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 2]

添加mybatis依赖：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 3]

填写项目位置：

![在这里插入图片描述][20181130154616449.png]

生成的项目结构：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 4]

依赖也已经全部自动引入：

<?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.czxy.demo</groupId>
    	<artifactId>user-service-demo</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<packaging>jar</packaging>
    
    	<name>user-service-demo</name>
    	<description>Demo project for Spring Boot</description>
    
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.0.4.RELEASE</version>
    		<relativePath/> 
    	</parent>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    		<java.version>1.8</java.version>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-jdbc</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.mybatis.spring.boot</groupId>
    			<artifactId>mybatis-spring-boot-starter</artifactId>
    			<version>1.3.2</version>
    		</dependency>
    
    		<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>
    
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    
    
    </project>

当然，因为要使用通用mapper，所以我们需要手动加一条依赖：

<dependency>
        <groupId>tk.mybatis</groupId>
        <artifactId>mapper-spring-boot-starter</artifactId>
        <version>2.0.2</version>
    </dependency>

ok！

**注意**：SpringCloud中mysql驱动包默认是8.x，太高了，可能会引起问题，所以需要修改成5.x

<dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.32</version>
    </dependency>

### 1.1.2.编写代码 ###

添加一个对外查询的接口：

@RestController
    @RequestMapping("user")
    public class UserController { 
    
        @Autowired
        private UserService userService;
    
        @GetMapping("/{id}")
        public User queryById(@PathVariable("id") Long id) { 
            return this.userService.queryById(id);
        }
    }

Service：

@Service
    public class UserService { 
    
        @Autowired
        private UserMapper userMapper;
    
        public User queryById(Long id) { 
            return this.userMapper.selectByPrimaryKey(id);
        }
    }

mapper:

@Mapper
    public interface UserMapper extends tk.mybatis.mapper.common.Mapper<User>{ 
    }

实体类：

@Table(name = "tb_user")
    public class User implements Serializable { 
    
        private static final long serialVersionUID = 1L;
    
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Long id;
    
        // 用户名
        private String userName;
    
        // 密码
        private String password;
    
        // 姓名
        private String name;
    
        // 年龄
        private Integer age;
    
        // 性别，1男性，2女性
        private Integer sex;
    
        // 出生日期
        private Date birthday;
    
        // 创建时间
        private Date created;
    
        // 更新时间
        private Date updated;
    
        // 备注
        private String note;
    
       // 。。。省略getters和setters
    }

属性文件,这里我们采用了yaml语法，而不是properties：

server:
      port: 8082
    spring:
      datasource:
        url: jdbc:mysql://localhost:3306/mydb1?useUnicode=true&characterEncoding=utf8
        username: root
        password: 123456
        driver-class-name: com.mysql.jdbc.Driver
      application:
        name: user-service # 应用名称
      main:
        allow-bean-definition-overriding: true #当遇到同样名字的时候，是否允许覆盖注册
    # druid:
    # initial-size: 1
    # min-idle: 1
    # max-active: 20
    # test-on-borrow: true
    # stat-view-servlet:
    # allow: true

项目结构：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 5]

### 1.1.3.启动并测试： ###

启动项目，访问接口：[http://localhost:8081/user/1][http_localhost_8081_user_1]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 6]

## 1.2.服务调用者 ##

### 1.2.1.创建工程 ###

与上面类似，这里不再赘述，需要注意的是，我们调用user-service的功能，因此不需要mybatis相关依赖了。

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 7]

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.czxy.demo</groupId>
    	<artifactId>user-consumer-demo</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<packaging>jar</packaging>
    
    	<name>user-consumer-demo</name>
    	<description>Demo project for Spring Boot</description>
    
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.0.1.RELEASE</version>
    		<relativePath/> 
    	</parent>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    		<java.version>1.8</java.version>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
        
    	</dependencies>
    
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    
    </project>

### 1.2.2.编写代码 ###

首先在启动类中注册`RestTemplate`：

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

然后编写UserDao，注意，这里不是调用mapper查数据库，而是通过RestTemplate远程查询user-service-demo中的接口：

@Component
    public class UserDao { 
    
        @Autowired
        private RestTemplate restTemplate;
    
        public User queryUserById(Long id){ 
            String url = "http://localhost:8081/user/" + id;
            return this.restTemplate.getForObject(url, User.class);
        }
    }

然后编写user-service，循环查询UserDAO信息：

@Service
    public class UserService { 
    
        @Autowired
        private UserDao userDao;
    
        public List<User> querUserByIds(List<Long> ids){ 
            List<User> users = new ArrayList<>();
            for (Long id : ids) { 
                User user = this.userDao.queryUserById(id);
                users.add(user);
            }
            return users;
        }
    }

编写controller：

@RestController
    @RequestMapping("consume")
    public class ConsumerController { 
    
        @Autowired
        private UserService userService;
    
        @GetMapping
        public List<User> consume(@RequestParam("ids") List<Long> ids) { 
            return this.userService.queryUserByIds(ids);
        }
    }

### 1.2.3.启动测试： ###

因为我们没有配置端口，那么默认就是8080，我们访问：[http://localhost:8080/consume?ids=1,2][http_localhost_8080_consume_ids_1_2]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 8]

一个简单的远程服务调用案例就实现了。

## 1.3 YAML语法 ##

**YAML: yet another markup language**

1.  大小写敏感
2.  使用缩进表示层级关系
3.  禁止使用tab缩进，只能使用空格键
4.  缩进长度没有限制，只要元素对齐就表示这些元素属于一个层级
5.  使用\#表示注释
6.  字符串可以不用引号标注

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70]: /images/20220412/598251d2dd0a429997305df812267c65.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 1]: /images/20220412/d5cfc18544e44c42bd2f324cefcb15ba.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 2]: /images/20220412/056ec43df41843a3a2552076952e272a.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 3]: /images/20220412/a9bb64272f5c47698cb7be7b72299e75.png
[20181130154616449.png]: /images/20220412/3077d0e2ffce4eadba20f4dc3c75f63b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 4]: /images/20220412/4e098ae915df4752ae709ab373ff0053.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 5]: /images/20220412/5c866454c66e4a20aaaf9a5763ae60c8.png
[http_localhost_8081_user_1]: http://localhost:8081/user/1
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 6]: /images/20220412/e1ad9f0612f24cde884099c38de0400d.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 7]: /images/20220412/6a09638743f4437e99f13a74f84bb484.png
[http_localhost_8080_consume_ids_1_2]: http://localhost:8080/consume?ids=1,2
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNjUyNTA5_size_16_color_FFFFFF_t_70 8]: /images/20220412/35e05cce2abd49a7b20274e33f873a8a.png