spring boot微服务-第三部分：创建货币兑换服务

作者: sstraybitd | 来源:发表于2020-03-09 12:51 被阅读0次

spring boot微服务-第三部分：创建货币兑换服务
Spring Boot之初体验
spring boot rest例子
Spring Boot 短信平台微服务
spring cloud开发微服务
Nacos 服务注册与发现实操
微服务那些事儿 2.技术实现
将springboot服务打包成docker镜像
Spring Cloud 技术栈及架构
Spring Cloud 微服务(二) 创建一个简单的服务

货币兑换服务

货币兑换服务（Currency Conversion Service CCS）能计算出将一定数量的货币转化为另一种货币的数量。它使用汇率服务（Forex Service，Fs，上一节介绍的服务）得到汇率。因此CCS是一个消费服务.

访问这个服务的请求和返回结果如下所示：

get请求：http://localhost:8100/currencyconverter/from/EUR/to/INR/quantity/10000

{
  id: 10002,
  from: "EUR",
  to: "INR",
  conversionMultiple: 75,
  quantity: 10000,
  totalCalculatedAmount: 750000,
  port: 8000,
}

上述请求是10000元欧元可以转换为多少卢比（750000卢比）。通信过程如下图所示

image.png

代码

创建bean
用于返回结果

public class CurrencyConversionBean {
  private Long id;
  private String from;
  private String to;
  private BigDecimal conversionMultiple;
  private BigDecimal quantity;
  private BigDecimal totalCalculatedAmount;
  private int port;

  public CurrencyConversionBean() {

  }

  public CurrencyConversionBean(Long id, String from, String to, BigDecimal conversionMultiple, BigDecimal quantity,
      BigDecimal totalCalculatedAmount, int port) {
    super();
    this.id = id;
    this.from = from;
    this.to = to;
    this.conversionMultiple = conversionMultiple;
    this.quantity = quantity;
    this.totalCalculatedAmount = totalCalculatedAmount;
    this.port = port;
  }

使用RestTemplate创建Rest客户端
调用FS服务并且处理返回的结果

@RestController
public class CurrencyConversionController {

  private Logger logger = LoggerFactory.getLogger(this.getClass());

  @GetMapping("/currency-converter/from/{from}/to/{to}/quantity/{quantity}")
  public CurrencyConversionBean convertCurrency(@PathVariable String from, @PathVariable String to,
      @PathVariable BigDecimal quantity) {

    Map<String, String> uriVariables = new HashMap<>();
    uriVariables.put("from", from);
    uriVariables.put("to", to);

    ResponseEntity<CurrencyConversionBean> responseEntity = new RestTemplate().getForEntity(
        "http://localhost:8000/currency-exchange/from/{from}/to/{to}", CurrencyConversionBean.class,
        uriVariables);

    CurrencyConversionBean response = responseEntity.getBody();

    return new CurrencyConversionBean(response.getId(), from, to, response.getConversionMultiple(), quantity,
        quantity.multiply(response.getConversionMultiple()), response.getPort());
  }

配置文件
application.properties

spring.application.name=currency-conversion-service
server.port=8100

测试
get请求：
http://localhost:8100/currency converter/from/EUR/to/INR/quantity/10000
返回：

{
  id: 10002,
  from: "EUR",
  to: "INR",
  conversionMultiple: 75,
  quantity: 10000,
  totalCalculatedAmount: 750000,
  port: 8000,
}

改进

创建代理(feign proxy)
调用Rest Api而不直接使用URL的方式

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.cloud.netflix.ribbon.RibbonClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

@FeignClient(name="forex-service" url="localhost:8000")
public interface CurrencyExchangeServiceProxy {
  @GetMapping("/currency-exchange/from/{from}/to/{to}")
  public CurrencyConversionBean retrieveExchangeValue
    (@PathVariable("from") String from, @PathVariable("to") String to);
}

说明

@FeignClient(name="forex-service" url="localhost:800")
声明这是一个代理，name指示代理的服务名称，url是代理的URL
@GetMapping("/currency-exchange/from/{from}/to/{to}")
服务的URI

在控制器中使用代理

@Autowired
  private CurrencyExchangeServiceProxy proxy;

  @GetMapping("/currency-converter-feign/from/{from}/to/{to}/quantity/{quantity}")
  public CurrencyConversionBean convertCurrencyFeign(@PathVariable String from, @PathVariable String to,
      @PathVariable BigDecimal quantity) {

    CurrencyConversionBean response = proxy.retrieveExchangeValue(from, to);

    logger.info("{}", response);

    return new CurrencyConversionBean(response.getId(), from, to, response.getConversionMultiple(), quantity,
        quantity.multiply(response.getConversionMultiple()), response.getPort());
  }

开启代理功能

@SpringBootApplication
@EnableFeignClients("com.zhg.springboot.microservice.example.currencyconversion")
@EnableDiscoveryClient
public class SpringBootMicroserviceCurrencyConversionApplication {

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

对微服务进行测试，使用代理的方式
get请求：
http://localhost:8100/currency-converter feign/from/EUR/to/INR/quantity/10000
返回

{
  id: 10002,
  from: "EUR",
  to: "INR",
  conversionMultiple: 75,
  quantity: 10000,
  totalCalculatedAmount: 750000,
  port: 8000,
}

完整代码

pom.xml

<?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.zhg.springboot.microservice.example.currency-conversion</groupId>
  <artifactId>spring-boot-microservice-currency-conversion</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>spring-boot-microservice-currency-conversion</name>
  <description>Microservices with Spring Boot and Spring Cloud - Currency Conversion Service</description>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.0.RELEASE</version>
    <relativePath /> <!-- lookup parent from repository -->
  </parent>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <spring-cloud.version>Finchley.M8</spring-cloud.version>
  </properties>

  <dependencies>

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

    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-devtools</artifactId>
      <scope>runtime</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-dependencies</artifactId>
        <version>${spring-cloud.version}</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>

  <repositories>
    <repository>
      <id>spring-snapshots</id>
      <name>Spring Snapshots</name>
      <url>https://repo.spring.io/snapshot</url>
      <snapshots>
        <enabled>true</enabled>
      </snapshots>
    </repository>
    <repository>
      <id>spring-milestones</id>
      <name>Spring Milestones</name>
      <url>https://repo.spring.io/milestone</url>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
    </repository>
  </repositories>

  <pluginRepositories>
    <pluginRepository>
      <id>spring-snapshots</id>
      <name>Spring Snapshots</name>
      <url>https://repo.spring.io/snapshot</url>
      <snapshots>
        <enabled>true</enabled>
      </snapshots>
    </pluginRepository>
    <pluginRepository>
      <id>spring-milestones</id>
      <name>Spring Milestones</name>
      <url>https://repo.spring.io/milestone</url>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
    </pluginRepository>
  </pluginRepositories>


</project>

CurrencyConversionBean.java

package com.zhg.springboot.microservice.example.currencyconversion;
import java.math.BigDecimal;

public class CurrencyConversionBean {
  private Long id;
  private String from;
  private String to;
  private BigDecimal conversionMultiple;
  private BigDecimal quantity;
  private BigDecimal totalCalculatedAmount;
  private int port;

  public CurrencyConversionBean() {

  }

  public CurrencyConversionBean(Long id, String from, String to, BigDecimal conversionMultiple, BigDecimal quantity,
      BigDecimal totalCalculatedAmount, int port) {
    super();
    this.id = id;
    this.from = from;
    this.to = to;
    this.conversionMultiple = conversionMultiple;
    this.quantity = quantity;
    this.totalCalculatedAmount = totalCalculatedAmount;
    this.port = port;
  }

  public Long getId() {
    return id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public String getFrom() {
    return from;
  }

  public void setFrom(String from) {
    this.from = from;
  }

  public String getTo() {
    return to;
  }

  public void setTo(String to) {
    this.to = to;
  }

  public BigDecimal getConversionMultiple() {
    return conversionMultiple;
  }

  public void setConversionMultiple(BigDecimal conversionMultiple) {
    this.conversionMultiple = conversionMultiple;
  }

  public BigDecimal getQuantity() {
    return quantity;
  }

  public void setQuantity(BigDecimal quantity) {
    this.quantity = quantity;
  }

  public BigDecimal getTotalCalculatedAmount() {
    return totalCalculatedAmount;
  }

  public void setTotalCalculatedAmount(BigDecimal totalCalculatedAmount) {
    this.totalCalculatedAmount = totalCalculatedAmount;
  }

  public int getPort() {
    return port;
  }

  public void setPort(int port) {
    this.port = port;
  }

}

CurrencyConversionController.java

package com.zhg.springboot.microservice.example.currencyconversion;

import java.math.BigDecimal;
import java.util.HashMap;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class CurrencyConversionController {

  private Logger logger = LoggerFactory.getLogger(this.getClass());

  @Autowired
  private CurrencyExchangeServiceProxy proxy;

  @GetMapping("/currency-converter/from/{from}/to/{to}/quantity/{quantity}")
  public CurrencyConversionBean convertCurrency(@PathVariable String from, @PathVariable String to,
      @PathVariable BigDecimal quantity) {

    Map<String, String> uriVariables = new HashMap<>();
    uriVariables.put("from", from);
    uriVariables.put("to", to);

    ResponseEntity<CurrencyConversionBean> responseEntity = new RestTemplate().getForEntity(
        "http://localhost:8000/currency-exchange/from/{from}/to/{to}", CurrencyConversionBean.class,
        uriVariables);

    CurrencyConversionBean response = responseEntity.getBody();

    return new CurrencyConversionBean(response.getId(), from, to, response.getConversionMultiple(), quantity,
        quantity.multiply(response.getConversionMultiple()), response.getPort());
  }

  @GetMapping("/currency-converter-feign/from/{from}/to/{to}/quantity/{quantity}")
  public CurrencyConversionBean convertCurrencyFeign(@PathVariable String from, @PathVariable String to,
      @PathVariable BigDecimal quantity) {

    CurrencyConversionBean response = proxy.retrieveExchangeValue(from, to);

    logger.info("{}", response);

    return new CurrencyConversionBean(response.getId(), from, to, response.getConversionMultiple(), quantity,
        quantity.multiply(response.getConversionMultiple()), response.getPort());
  }

}

CurrencyExchangeServiceProxy.java

package com.zhg.springboot.microservice.example.currencyconversion;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.cloud.netflix.ribbon.RibbonClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

@FeignClient(name="forex-service" url="localhost:8000")
public interface CurrencyExchangeServiceProxy {
  @GetMapping("/currency-exchange/from/{from}/to/{to}")
  public CurrencyConversionBean retrieveExchangeValue
    (@PathVariable("from") String from, @PathVariable("to") String to);
}

SpringBootMicroserviceCurrencyConversionApplication.java

package com.zhg.springboot.microservice.example.currencyconversion;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;

@SpringBootApplication
@EnableFeignClients("com.in28minutes.springboot.microservice.example.currencyconversion")
public class SpringBootMicroserviceCurrencyConversionApplication {

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

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