• 编写服务提供者
  • 编写服务消费者

微服务构建的是分布式系统,各个微服务之间通过网络进行通信。一般我们用服务提供者和服务消费者来描述微服务之间的调用关系:

服务提供者

服务被调用方

服务消费者

服务的调用方

以售票系统为例,用户向12306售票系统发起购票请求,在进行购买业务之前,12306售票系统需要先调用用户微服务接口,查看用户的相关信息是否符合购买标准等相关信息,这里,用户微服务就是服务的提供者,售票系统微服务就是服务消费者。下面依次在Intellij idea中手动创建这两个微服务:

先创建用户微服务:maven的pom.xml文件信息如下:

<?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.simons.cn</groupId>
    <artifactId>user-provider</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.3.RELEASE</version>
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.7</java.version>
    </properties>
    <dependencies>
        <!--支持web应该用开发,包括spring-mvc、jackson、tomcat、spring-webmvc-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--springboot Actuator提供了众多检测端点,了解应用程序的运行状况-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!--配置mybatis启动器依赖-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.2.0</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.22</version>
        </dependency>
        <!--lombok依赖-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.12</version>
            <scope>provided</scope>
        </dependency>

    </dependencies>
    <!-- 引入spring cloud的依赖 -->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Camden.SR4</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <!-- 添加spring-boot的maven插件 -->
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

生成项目后,把通过mybatis反向生成的实体和xml文件copy到相关目录(mybatis反向生成点这里),目录如图:

这里要注意要修改UserMapper.xml中Mapper和User类为你实际路径。

接着编写启动类ProviderUserApplication:

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

//扫描*Mapper.java接口文件
@MapperScan("com.simons.cn.mapper")
@SpringBootApplication
public class PrividerUserApplication {
    public static void main(String[] args) {
        SpringApplication.run(PrividerUserApplication.class);
    }
}

@SpringBootApplication是一个组合注解,它整合了@Configuration、@EnableAutoConfiguration和@ComponentScan注解,并且开启了springboot程序组件扫描和自动配置功能;@MapperScan注解用来扫描mapper接口。

接着编写UserController类:

import com.simons.cn.bean.User;
import com.simons.cn.service.UserServiceImpl;
import com.simons.cn.util.CommonEnum;
import com.simons.cn.util.CommonResult;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;

@Slf4j
@RestController
public class UserController {

    @Autowired
    private UserServiceImpl userService;

    @GetMapping(value = "/getuserinfo")
    public CommonResult getUserInfo(@RequestParam(required = false,value = "name") String name){
        List<User> userList = userService.getUserByName(name);
        return CommonResult.success(CommonEnum.SUCESS.getCode(),CommonEnum.SUCESS.getMessage(),userList);
    }
}

@RestController注解声明等价于@Controller和@ResponseBody注解联合作用,标识该类均返回一个rest风格的data;@GetMapping是spring4.3提供的新注解,等价于@RequestMapping(value="/{id}",method=RequestMethod.GET),同理还有@PostMapping()等。

接着编写配置文件application.yml或application.properties均可,我这里是application.yml

server:
  port: 8000
# 数据库连接信息
spring:
  datasource:
           url: jdbc:mysql://×××:3306/simons?rewriteBatchedStatements=true&characterEncoding=utf-8
           username: ×××
           password: ×××
           driver-class-name: com.mysql.jdbc.Driver
# mybatis扫描信息
mybatis:
  typeAliasesPackage: com.simonsfan.study.bean  #实体对象所以在包
  mapper-locations: classpath:mapper/*.xml       #xml文件位置

需要注意的是,yml文件中冒号后面要空一格,例如port: 8000冒号后面一定要空格再接8000

接下来可以启动ProviderUserApplication启动类。

测试:浏览器访问http://localhost:8000/getuserinfo?name=jack,返回

{
  "code": "0",
  "message": "success",
  "data": [{
    "id": 125,
    "name": "jack",
    "role": "system"}]
}

这样,用户微服务就顺利完成。同理,可以编写售票系统的服务消费者。pom.xml文件基本不变

<?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.simons.cn</groupId>
    <artifactId>ticket-coucumer</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.3.RELEASE</version>
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.7</java.version>
    </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>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.22</version>
        </dependency>
        <!--lombok依赖-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.12</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>
    <!-- 引入spring cloud的依赖 -->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Camden.SR4</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <!-- 添加spring-boot的maven插件 -->
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

接着我把刚才服务提供者里面要用的一些类都copy到服务消费者来,目录结构如下:

编写启动类ConsumerApplication:

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
public class ConsumerApplication {

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

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

其中@Bean是一个方法注解,作用是实例化一个Bean并使用该方法的名称命名,本例中的用法等价于RestTemplate restTemplate = new RestTemplate()

接着创建TicketController:

import com.simons.cn.util.CommonResult;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@Slf4j
@RestController
public class TicketController {

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/ticketpurchase")
    public CommonResult purchaseTicket(@RequestParam(required = false,value = "name") String name){
        //模拟判断用户身份
        CommonResult result = restTemplate.getForObject("http://localhost:8000/getuserinfo?name=" + name, CommonResult.class);
        //买票下单逻辑略
        return result;
    }

}

这里要注意的是,刚才编写的CommonResult类中一定要添加无参构造函数,否则上面的调用会报错!!!

编写application.yml文件:

server:
  port: 8888

这样,售票微服务也完成了。启动ConsumerApplication启动类

测试:浏览器访问:http://localhost:9000/ticketpurchase?name=jack,结果如下:

{
  "code": "0",
  "message": "success",
  "data": [{
    "id": 125,
    "name": "jack",
    "role": "system"
    }]
}

说明售票微服务已经可以正常使用RestTemplate和用户微服务API通信了。

项目的github:https://github.com/simonsfan/SpringCloud.git

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