从akka http javadsl ResponseEntity中提取响应json字符串

import akka.actor.ActorSystem;
import akka.http.javadsl.Http;
import akka.http.javadsl.model.HttpRequest;
import akka.http.javadsl.model.HttpResponse;
import akka.http.javadsl.model.StatusCodes;
import akka.http.javadsl.unmarshalling.Unmarshaller;
import akka.stream.ActorMaterializer;
import akka.stream.javadsl.Framing;
import akka.util.ByteString;

import java.util.concurrent.CompletionStage;

public class JsonExtractor {
    public static void main(String[] args) {
        // 创建Actor系统和材料化器
        ActorSystem system = ActorSystem.create();
        ActorMaterializer materializer = ActorMaterializer.create(system);

        // 创建HTTP客户端
        Http http = Http.get(system);

        // 创建HTTP请求
        HttpRequest request = HttpRequest.GET("https://example.com/api");

        // 发送HTTP请求并获取响应
        CompletionStage<HttpResponse> responseFuture = http.singleRequest(request, materializer);

        // 处理响应
        responseFuture.thenCompose(response -> {
            // 检查响应状态码
            if (response.status().equals(StatusCodes.OK)) {
                // 获取响应实体
                return response.entity().getDataBytes()
                        // 分割数据流
                        .via(Framing.delimiter(ByteString.fromString("\n"), 100))
                        // 将每个块转换为字符串
                        .map(ByteString::utf8String)
                        // 合并所有字符串块
                        .runFold("", (acc, str) -> acc + str, materializer)
                        .thenApply(jsonString -> {
                            // 在这里处理JSON字符串
                            System.out.println(jsonString);
                            return jsonString;
                        });
            } else {
                throw new RuntimeException("请求失败，状态码：" + response.status());
            }
        }).exceptionally(ex -> {
            // 处理异常
            System.err.println("请求出错：" + ex.getMessage());
            return null;
        });
    }
}