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java如何获取汇率

2026-03-25 23:30:00Java

获取汇率的方法

使用Java获取汇率可以通过多种方式实现，包括调用公开的API、解析网页数据或使用第三方库。以下是几种常见的方法：

调用汇率API

许多金融数据提供商和网站提供免费的汇率API，例如ExchangeRate-API、Open Exchange Rates等。以下是使用ExchangeRate-API的示例代码：

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class ExchangeRateFetcher {
    public static void main(String[] args) {
        try {
            String apiKey = "YOUR_API_KEY";
            String fromCurrency = "USD";
            String toCurrency = "EUR";
            String urlStr = "https://v6.exchangerate-api.com/v6/" + apiKey + "/pair/" + fromCurrency + "/" + toCurrency;

            URL url = new URL(urlStr);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");

            BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String line;
            StringBuilder response = new StringBuilder();

            while ((line = reader.readLine()) != null) {
                response.append(line);
            }
            reader.close();

            System.out.println("Exchange rate: " + response.toString());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

使用第三方库

某些Java库简化了汇率数据的获取过程。例如，使用unirest-java库可以更简洁地调用API：

import com.mashape.unirest.http.Unirest;
import com.mashape.unirest.http.exceptions.UnirestException;

public class ExchangeRateUnirest {
    public static void main(String[] args) {
        try {
            String apiKey = "YOUR_API_KEY";
            String response = Unirest.get("https://v6.exchangerate-api.com/v6/" + apiKey + "/pair/USD/EUR")
                    .asString()
                    .getBody();
            System.out.println("Exchange rate: " + response);
        } catch (UnirestException e) {
            e.printStackTrace();
        }
    }
}

解析网页数据

如果API不可用，可以通过解析网页内容获取汇率。例如，使用jsoup库解析网页：

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;

public class WebScraper {
    public static void main(String[] args) {
        try {
            Document doc = Jsoup.connect("https://www.x-rates.com/calculator/?from=USD&to=EUR&amount=1").get();
            Element rateElement = doc.select(".ccOutputRslt").first();
            String rate = rateElement.text().split(" ")[0];
            System.out.println("Exchange rate: " + rate);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

使用Java内置功能

对于简单的需求，可以通过Java内置的HttpClient（Java 11及以上版本）获取数据：

java如何获取汇率

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class ExchangeRateHttpClient {
    public static void main(String[] args) {
        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://api.exchangerate-api.com/v4/latest/USD"))
                .build();

        client.sendAsync(request, HttpResponse.BodyHandlers.ofString())
                .thenApply(HttpResponse::body)
                .thenAccept(System.out::println)
                .join();
    }
}