内容:
- 实现目标的行动计划
- 探索 Skyscanner API
- 创建基于Spring Boot的应用程序框架
- 我们正在为项目中的 Skyscanner Flight Search API 编写一个客户端请求
- 为本地化请求创建客户端服务
- REST 以及 REST 端点的构建方式;
- 关系数据库;
- maven的工作(特别是什么是依赖);
- JSON 对象;
- 日志记录原则。
- 您可以选择特定日期的航班并跟踪其价格。用户通过电子邮件地址进行识别。一旦订阅价格变更,用户就会收到电子邮件通知。
- 每 30 分钟(此间隔通过 application.properties 配置),将为所有订阅重新计算一次航班的最低价格。如果其中一个值变低,用户将收到电子邮件通知。
- 所有航班日期已过期的订阅都将被删除。
- 通过 REST API,您可以:
- 创建订阅;
- 编辑;
- 通过电子邮件接收所有订阅;
- 删除订阅。
实现目标的行动计划
您需要从以下事实开始:需要从某个地方获取有关航班的信息。通常,网站提供开放的 REST API,通过该 API 可以检索信息。
API(应用程序编程接口)是您可以与应用程序交互的接口。由此我们可以构建一座通向 REST API 的桥梁。 REST API 是 REST 请求的接口,可用于与 Web 应用程序进行通信。 |
探索 Skyscanner API
让我们点击rakuten api的链接。首先您需要注册。 所有这些都需要接收唯一密钥才能使用其网站并向发布在其上的公共 API 发出请求。我们需要的Skyscanner Flight Search就是这些 API 之一。现在让我们弄清楚它是如何工作的。让我们找到 GET List Places 请求。如图所示,您需要填写数据并启动Test Endpoint,结果我们会收到右侧 JSON 对象形式的响应: 并且将像这样创建请求:
https://skyscanner-skyscanner-flight-search-v1.p.rapidapi.com/apiservices/autosuggest/v1.0/{country}/{currency}/{locale}/?query={query}
将所有参数代入该公式,得:
https://skyscanner-skyscanner-flight-search-v1.p.rapidapi.com/apiservices/autosuggest/v1.0/UK/GBP/en-GB/?query=Stockholm
并且两个标头将传递给这些请求:
.header("x-rapidapi-host", "skyscanner-skyscanner-flight-search-v1.p.rapidapi.com")
.header("x-rapidapi-key", "sing-up-for-key"),
sign-up-for-key
注册后颁发的 地方。为了跟踪价格下跌,我们需要浏览报价端点。自己找吧:)
创建基于Spring Boot的应用程序框架
要使用 Spring Boot 快速轻松地创建项目,您可以使用Spring Initializr。选择以下选项:- Maven项目
- 爪哇
- 2.1.10
- 组 - 无论您认为有必要,例如 ru.javarush
- 工件 - 完全相同,例如航班监控
- 在依赖性搜索中,我们寻找以下内容:
- 春季网
- Java邮件发送器
- Spring数据Jpa
- H2数据库
- 控制器 - 登录到应用程序。这里将描述 REST API
- SERVICE是业务逻辑层。这里将描述应用程序的整个逻辑。
- REPOSITORY - 用于处理数据库的层。
我们正在为项目中的 Skyscanner Flight Search API 编写一个客户端请求
Skyscanner 提供了一篇有关如何使用其 API 的文章(我们不会创建带有活动请求的会话)。“写客户”是什么意思?我们需要使用某些参数创建对特定 URL 的请求,并为传回给我们的数据准备一个 DTO(数据传输对象)。网站上有四组请求:- 实时航班搜索 - 目前我们认为没有必要。
- 地方——让我们写吧。
- 浏览航班价格 - 我们将使用一个请求,您可以在其中获取所有信息。
- 本地化 - 让我们添加它以便我们知道支持哪些数据。
为本地化请求创建客户端服务:
该计划就像蒸萝卜一样简单:创建请求,查看参数,查看响应。有两个查询:列表标记和货币。让我们从货币开始。从图中可以看出,这是一个没有附加字段的请求:需要获取支持的货币信息: 响应是JSON对象的形式,其中包含相同对象的集合,例如:{
"Code":"LYD"
"Symbol":"د.ل."
"ThousandsSeparator":","
"DecimalSeparator":"."
"SymbolOnLeft":true
"SpaceBetweenAmountAndSymbol":false
"RoundingCoefficient":0
"DecimalDigits":3
}
让我们为此对象创建一个CurrencyDto:
import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.Data;
/**
* Data transfer object for Currency.
*/
@Data
public class CurrencyDto {
@JsonProperty("Code")
private String code;
@JsonProperty("Symbol")
private String symbol;
@JsonProperty("ThousandsSeparator")
private String thousandsSeparator;
@JsonProperty("DecimalSeparator")
private String decimalSeparator;
@JsonProperty("SymbolOnLeft")
private boolean symbolOnLeft;
@JsonProperty("SpaceBetweenAmountAndSymbol")
private boolean spaceBetweenAmountAndSymbol;
@JsonProperty("RoundingCoefficient")
private int roundingCoefficient;
@JsonProperty("DecimalDigits")
private int decimalDigits;
}
在哪里:
- @Data 是来自Lombok 项目的注释,可生成所有 getter、setter,并覆盖 toString()、equals() 和 hashCode() 方法。什么提高了代码可读性并加快了编写POJO对象的时间;
- @JsonProperty("Code") 是来自 Jackson Project 的注释,它告诉将哪个字段分配给该变量。也就是说,JSON 中等于 Code 的字段将被分配给code变量。
<dependency>
<groupId>com.mashape.unirest</groupId>
<artifactId>unirest-java</artifactId>
<version>1.4.9</version>
</dependency>
接下来,我们将编写一个执行 REST 请求的服务。当然,对于每个客户端/服务,我们将创建一个接口及其实现:
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.JsonNode;
/**
* Service, which is manipulating with Rest calls.
*/
public interface UniRestService {
/**
* Create GET request based on provided {@param path} with needed headers.
*
* @param path provided path with all the needed data
* @return {@link HttpResponse<jsonnode>} response object.
*/
HttpResponse<jsonnode> get(String path);
}
及其实现:
import com.github.romankh3.flightsmonitoring.exception.FlightClientException;
import com.github.romankh3.flightsmonitoring.client.service.UniRestService;
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.JsonNode;
import com.mashape.unirest.http.Unirest;
import com.mashape.unirest.http.exceptions.UnirestException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
/**
* {@inheritDoc}
*/
@Slf4j
@Service
public class UniRestServiceImpl implements UniRestService {
public static final String HOST = "https://skyscanner-skyscanner-flight-search-v1.p.rapidapi.com";
public static final String PLACES_FORMAT = "/apiservices/autosuggest/v1.0/%s/%s/%s/?query=%s";
public static final String CURRENCIES_FORMAT = "/apiservices/reference/v1.0/currencies";
public static final String COUNTRIES_FORMAT = "/apiservices/reference/v1.0/countries/%s";
public static final String PLACES_KEY = "Places";
public static final String CURRENCIES_KEY = "Currencies";
public static final String COUNTRIES_KEY = "Countries";
@Value("${x.rapid.api.key}")
private String xRapidApiKey;
/**
* {@inheritDoc}
*/
@Override
public HttpResponse<jsonnode> get(String path) {
HttpResponse<jsonnode> response = null;
try {
response = Unirest.get(HOST + path)
.header("x-rapidapi-host", "skyscanner-skyscanner-flight-search-v1.p.rapidapi.com")
.header("x-rapidapi-key", xRapidApiKey)
.asJson();
} catch (UnirestException e) {
throw new FlightClientException(String.format("Request failed, path=%s", HOST + path), e);
}
log.info("Response from Get request, on path={}, statusCode={}, response={}", path, response.getStatus(), response.getBody().toString());
return response;
}
}
它的本质是我们感兴趣的所有请求都是为 GET 请求创建的,并且该服务接受现成的请求并添加必要的标头,例如:
.header("x-rapidapi-host", "skyscanner-skyscanner-flight-search-v1.p.rapidapi.com")
.header("x-rapidapi-key", xRapidApiKey)
要从属性中获取数据,请使用 @Value 注释,如下所示:
@Value("${x.rapid.api.key}")
private String xRapidApiKey;
它说在application.properties中会有一个名为x.rapid.api.key的属性,需要将其注入到该变量中。我们摆脱了硬编码值,并从程序代码中导出该变量的定义。此外,当我在 GitHub 上发布此应用程序时,我没有添加此属性的值。这样做是出于安全原因。我们已经编写了一个可以处理 REST 请求的服务,现在是时候提供本地化服务了。我们正在构建一个基于 OOP 的应用程序,因此我们创建LocalizationClient接口及其实现LocalizationClientImpl:
import com.github.romankh3.flightsmonitoring.client.dto.CountryDto;
import com.github.romankh3.flightsmonitoring.client.dto.CurrencyDto;
import java.io.IOException;
import java.util.List;
/**
* Client for SkyScanner localisation.
*/
public interface LocalisationClient {
/**
* Retrieve the market countries that SkyScanner flight search API support. Most suppliers (airlines,
* travel agents and car hire dealers) set their fares based on the market (or country of purchase).
* It is therefore necessary to specify the market country in every query.
*
* @param locale locale of the response.
*
* @return the collection of the {@link CountryDto} objects.
*
* @throws IOException
*/
List<CountryDto> retrieveCountries(String locale);
/**
* Retrieve the currencies that we ScyScanner flight search API.
*
* @return the collection of the {@link CurrencyDto} objects.
*
* @throws IOException
*/
List<CurrencyDto> retrieveCurrencies();
}
和 LocalizationClientImpl 的实现
import static com.github.romankh3.flightsmonitoring.client.service.impl.UniRestServiceImpl.COUNTRIES_FORMAT;
import static com.github.romankh3.flightsmonitoring.client.service.impl.UniRestServiceImpl.COUNTRIES_KEY;
import static com.github.romankh3.flightsmonitoring.client.service.impl.UniRestServiceImpl.CURRENCIES_FORMAT;
import static com.github.romankh3.flightsmonitoring.client.service.impl.UniRestServiceImpl.CURRENCIES_KEY;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.github.romankh3.flightsmonitoring.client.dto.CountryDto;
import com.github.romankh3.flightsmonitoring.client.dto.CurrencyDto;
import com.github.romankh3.flightsmonitoring.client.service.LocalisationClient;
import com.github.romankh3.flightsmonitoring.client.service.UniRestService;
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.JsonNode;
import com.mashape.unirest.http.exceptions.UnirestException;
import java.io.IOException;
import java.util.List;
import org.apache.http.HttpStatus;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
/**
* {@inheritDoc}
*/
@Component
public class LocalisationClientImpl implements LocalisationClient {
@Autowired
private UniRestService uniRestService;
@Autowired
private ObjectMapper objectMapper;
/**
* {@inheritDoc}
*/
@Override
public List<CountryDto> retrieveCountries(String locale) throws IOException {
HttpResponse<JsonNode> response = uniRestService.get(String.format(COUNTRIES_FORMAT, locale));
if (response.getStatus() != HttpStatus.SC_OK) {
return null;
}
String jsonList = response.getBody().getObject().get(COUNTRIES_KEY).toString();
return objectMapper.readValue(jsonList, new TypeReference<List<CountryDto>>() {
});
}
/**
* {@inheritDoc}
*/
@Override
public List<CurrencyDto> retrieveCurrencies() throws IOException, UnirestException {
HttpResponse<JsonNode> response = uniRestService.get(CURRENCIES_FORMAT);
if (response.getStatus() != HttpStatus.SC_OK) {
return null;
}
String jsonList = response.getBody().getObject().get(CURRENCIES_KEY).toString();
return objectMapper.readValue(jsonList, new TypeReference<List<CurrencyDto>>() {
});
}
}
在哪里
- @Autowired是一个注解,表示需要向这个类中注入一个对象并使用它,而不需要创建它,即不需要new Object操作;
- @Component 是一个注解,表示必须将此对象添加到应用程序上下文中,以便稍后可以使用 @Autowired 注解进行注入;
- ObjectMapper objectMapper 是 Jackson Project 中的一个对象,它将所有这些转换为 Java 对象。
- 货币DTO和国家DTO:
import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.Data;
/**
* Data transfer object for Currency.
*/
@Data
public class CurrencyDto {
@JsonProperty("Code")
private String code;
@JsonProperty("Symbol")
private String symbol;
@JsonProperty("ThousandsSeparator")
private String thousandsSeparator;
@JsonProperty("DecimalSeparator")
private String decimalSeparator;
@JsonProperty("SymbolOnLeft")
private boolean symbolOnLeft;
@JsonProperty("SpaceBetweenAmountAndSymbol")
private boolean spaceBetweenAmountAndSymbol;
@JsonProperty("RoundingCoefficient")
private int roundingCoefficient;
@JsonProperty("DecimalDigits")
private int decimalDigits;
}
и
import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.Data;
/**
* Data transfer object for Country.
*/
@Data
public class CountryDto {
@JsonProperty("Code")
private String code;
@JsonProperty("Name")
private String name;
}
为了将 ObjectMapper 注入项目的任何部分,我添加了通过配置类创建并将其添加到 ApplicationContext 中。
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
* {@link Configuration} class.
*/
@Configuration
public class Config {
@Bean
public ObjectMapper objectMapper() {
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.registerModule(new JavaTimeModule());
return objectMapper;
}
}
@Configuration注解告诉Spring这个类中会有一些配置。为此我添加了 ObjectMapper。同样,我们添加 PlacesClient 和 PlacesClientImpl:
import com.github.romankh3.flightsmonitoring.client.dto.PlaceDto;
import com.github.romankh3.flightsmonitoring.client.dto.PlacesDto;
import com.mashape.unirest.http.exceptions.UnirestException;
import java.io.IOException;
import java.util.List;
/**
* SkyScanner client.
*/
public interface PlacesClient {
/**
* Get a list of places that match a query string based on arguments.
*
* @param query the code of the city.
* @param country the code of the country.
* @param currency the code of the currency.
* @param locale the code of the locale.
* @return the collection of the {@link PlaceDto} objects.
*/
List<PlacesDto> retrieveListPlaces(String query, String country, String currency, String locale)
throws IOException, UnirestException;
}
和
import static com.github.romankh3.flightsmonitoring.client.service.impl.UniRestServiceImpl.PLACES_FORMAT;
import static com.github.romankh3.flightsmonitoring.client.service.impl.UniRestServiceImpl.PLACES_KEY;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.github.romankh3.flightsmonitoring.client.dto.PlacesDto;
import com.github.romankh3.flightsmonitoring.client.service.PlacesClient;
import com.github.romankh3.flightsmonitoring.client.service.UniRestService;
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.JsonNode;
import com.mashape.unirest.http.exceptions.UnirestException;
import java.io.IOException;
import java.util.List;
import org.apache.http.HttpStatus;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
/**
* {@inheritDoc}
*/
@Service
public class PlacesClientImpl implements PlacesClient {
@Autowired
private UniRestService uniRestService;
@Autowired
private ObjectMapper objectMapper;
/**
* {@inheritDoc}
*/
@Override
public List<PlacesDto> retrieveListPlaces(String query, String country, String currency, String locale)
throws IOException, UnirestException {
HttpResponse<JsonNode> response = uniRestService
.get(String.format(PLACES_FORMAT, country, currency, locale, query));
if (response.getStatus() != HttpStatus.SC_OK) {
return null;
}
String jsonList = response.getBody().getObject().get(PLACES_KEY).toString();
return objectMapper.readValue(jsonList, new TypeReference<List<PlacesDto>>() {
});
}
}
其中 PlacesDto 的形式为:
import com.fasterxml.jackson.annotation.JsonProperty;
import com.github.romankh3.flightsmonitoring.client.service.PlacesClient;
import lombok.Data;
/**
* Using for {@link PlacesClient}.
*/
@Data
public class PlacesDto {
@JsonProperty("PlaceId")
private String placeId;
@JsonProperty("PlaceName")
private String placeName;
@JsonProperty("CountryId")
private String countryId;
@JsonProperty("RegionId")
private String regionId;
@JsonProperty("CityId")
private String cityId;
@JsonProperty("CountryName")
private String countryName;
}
最后,客户端服务将根据必要的数据返回航班的最低价格和所有必要的信息:FlightPriceClient 和 FlightPriceClientImpl。我们将只实现一个请求,browseQuotes。航班价格客户:
import com.github.romankh3.flightsmonitoring.client.dto.FlightPricesDto;
/**
* Browse flight prices.
*/
public interface FlightPricesClient {
/**
* Browse quotes for current flight based on provided arguments. One-way ticket.
*
* @param country the country from
* @param currency the currency to get price
* @param locale locale for the response
* @param originPlace origin place
* @param destinationPlace destination place
* @param outboundPartialDate outbound date
* @return {@link FlightPricesDto} object.
*/
FlightPricesDto browseQuotes(String country, String currency, String locale, String originPlace,
String destinationPlace, String outboundPartialDate);
/**
* Browse quotes for current flight based on provided arguments. Round trip ticket.
*
* @param country the country from
* @param currency the currency to get price
* @param locale locale for the response
* @param originPlace origin place
* @param destinationPlace destination place
* @param outboundPartialDate outbound date
* @param inboundPartialDate inbound date
* @return {@link FlightPricesDto} object.
*/
FlightPricesDto browseQuotes(String country, String currency, String locale, String originPlace,
String destinationPlace, String outboundPartialDate, String inboundPartialDate);
}
FlightPriceClientImpl
import static com.github.romankh3.flightsmonitoring.client.service.impl.UniRestServiceImpl.CURRENCIES_KEY;
import static com.github.romankh3.flightsmonitoring.client.service.impl.UniRestServiceImpl.PLACES_KEY;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.github.romankh3.flightsmonitoring.client.dto.CarrierDto;
import com.github.romankh3.flightsmonitoring.client.dto.CurrencyDto;
import com.github.romankh3.flightsmonitoring.client.dto.FlightPricesDto;
import com.github.romankh3.flightsmonitoring.client.dto.PlaceDto;
import com.github.romankh3.flightsmonitoring.client.dto.QuoteDto;
import com.github.romankh3.flightsmonitoring.client.dto.ValidationErrorDto;
import com.github.romankh3.flightsmonitoring.client.service.FlightPricesClient;
import com.github.romankh3.flightsmonitoring.client.service.UniRestService;
import com.github.romankh3.flightsmonitoring.exception.FlightClientException;
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.JsonNode;
import java.io.IOException;
import java.util.List;
import org.apache.http.HttpStatus;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
/**
* {@inheritDoc}
*/
@Service
public class FlightPricesClientImpl implements FlightPricesClient {
public static final String BROWSE_QUOTES_FORMAT = "/apiservices/browsequotes/v1.0/%s/%s/%s/%s/%s/%s";
public static final String OPTIONAL_BROWSE_QUOTES_FORMAT = BROWSE_QUOTES_FORMAT + "?inboundpartialdate=%s";
public static final String QUOTES_KEY = "Quotes";
public static final String ROUTES_KEY = "Routes";
public static final String DATES_KEY = "Dates";
public static final String CARRIERS_KEY = "Carriers";
public static final String VALIDATIONS_KEY = "ValidationErrors";
@Autowired
private UniRestService uniRestService;
@Autowired
private ObjectMapper objectMapper;
/**
* {@inheritDoc}
*/
@Override
public FlightPricesDto browseQuotes(String country, String currency, String locale, String originPlace,
String destinationPlace, String outboundPartialDate) {
HttpResponse<JsonNode> response = uniRestService.get(String
.format(BROWSE_QUOTES_FORMAT, country, currency, locale, originPlace, destinationPlace,
outboundPartialDate));
return mapToObject(response);
}
public FlightPricesDto browseQuotes(String country, String currency, String locale, String originPlace,
String destinationPlace, String outboundPartialDate, String inboundPartialDate) {
HttpResponse<JsonNode> response = uniRestService.get(String
.format(OPTIONAL_BROWSE_QUOTES_FORMAT, country, currency, locale, originPlace, destinationPlace,
outboundPartialDate, inboundPartialDate));
return mapToObject(response);
}
private FlightPricesDto mapToObject(HttpResponse<JsonNode> response) {
if (response.getStatus() == HttpStatus.SC_OK) {
FlightPricesDto flightPricesDto = new FlightPricesDto();
flightPricesDto.setQuotas(readValue(response.getBody().getObject().get(QUOTES_KEY).toString(),
new TypeReference<List<QuoteDto>>() {
}));
flightPricesDto.setCarriers(readValue(response.getBody().getObject().get(CARRIERS_KEY).toString(),
new TypeReference<List<CarrierDto>>() {
}));
flightPricesDto.setCurrencies(readValue(response.getBody().getObject().get(CURRENCIES_KEY).toString(),
new TypeReference<List<CurrencyDto>>() {
}));
flightPricesDto.setPlaces(readValue(response.getBody().getObject().get(PLACES_KEY).toString(),
new TypeReference<List<PlaceDto>>() {
}));
return flightPricesDto;
}
throw new FlightClientException(String.format("There are validation errors. statusCode = %s", response.getStatus()),
readValue(response.getBody().getObject().get(VALIDATIONS_KEY).toString(),
new TypeReference<List<ValidationErrorDto>>() {
}));
}
private <T> List<T> readValue(String resultAsString, TypeReference<List<T>> valueTypeRef) {
List<T> list;
try {
list = objectMapper.readValue(resultAsString, valueTypeRef);
} catch (IOException e) {
throw new FlightClientException("Object Mapping failure.", e);
}
return list;
}
}
其中 FlightClientException 如下所示:
import com.github.romankh3.flightsmonitoring.client.dto.ValidationErrorDto;
import java.util.List;
/**
* A {@link RuntimeException} that is thrown in case of an flight monitoring failures.
*/
public final class FlightClientException extends RuntimeException {
public FlightClientException(String message) {
super(message);
}
public FlightClientException(String message, Throwable throwable) {
super(message, throwable);
}
public FlightClientException(String message, List<ValidationErrorDto> errors) {
super(message);
this.validationErrorDtos = errors;
}
private List<ValidationErrorDto> validationErrorDtos;
}
结果,根据 PlacesCl 的数据
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