無法在 Spring Boot 中使用 Resttemplate 將嵌套 JSON 轉換為 POJO

Question

我有以下 JSON，我想從中將特定字段存儲在數據庫中。

JSON對象

{
    "data": [
        {
            "screen_ID": "23",
            "screen_data": {
                "ob": "Yes",
                "next_page": 2,
                "news": [
                    {
                        "news_ID": 2844573,
                        "hash": "ef52eadab9d2bdf69b6a288e6de7797b",
                        "providerId": "73",
                        "itemCategoryTags": "301",
                        "news_provider_name": "CoinQuora",
                        "last_updated": "2022-07-06 16:00:38",
                        "last_updated_uts": 1657123238,
                        "type": "text",
                        "HEADLINE": "BTC, ETH, SHIB, STEPN, PancakeSwap: Top 5 Trending Coins",
                        "BODY": "",
                        "news_link": "https://www.investing.com/news/cryptocurrency-news/btc-eth-shib-stepn-pancakeswap-top-5-trending-coins-2844573",
                        "third_party_url": "",
                        "related_image": "https://i-invdn-com.investing.com/news/LYNXNPEE340J6_S.jpg",
                        "related_image_big": "https://i-invdn-com.investing.com/news/LYNXNPEE340J6_L.jpg",
                        "vid_filename": "",
                        "comments_cnt": "0",
                        "is_partial": "yes",
                        "itemType": "hosted",
                        "news_type": "AkapiAdmin"
                    },
                    {
                        "news_ID": 2844563,
                        "hash": "f671179bec5cc29409c00f89b9494b3f",
                        "providerId": "72",
                        "itemCategoryTags": "301",
                        "news_provider_name": "BTC Peers",
                        "last_updated": "2022-07-06 15:30:44",
                        "last_updated_uts": 1657121444,
                        "type": "text",
                        "HEADLINE": "Buy the Bitcoin dip, Wolf of Wall Street Jordan Belfort advises",
                        "BODY": "",
                        "news_link": "https://www.investing.com/news/cryptocurrency-news/buy-the-bitcoin-dip-wolf-of-wall-street-jordan-belfort-advises-2844563",
                        "third_party_url": "",
                        "related_image": "https://i-invdn-com.investing.com/news/LYNXNPEF310CO_S.jpg",
                        "related_image_big": "https://i-invdn-com.investing.com/news/LYNXNPEF310CO_L.jpg",
                        "vid_filename": "",
                        "comments_cnt": "0",
                        "is_partial": "yes",
                        "itemType": "hosted",
                        "news_type": "AkapiAdmin"
                    },
                    {
                        "news_ID": 2844549,
                        "hash": "b26f2704330df75e5df3a407f229b984",
                        "providerId": "43",
                        "itemCategoryTags": "301",
                        "news_provider_name": "Cointelegraph",
                        "last_updated": "2022-07-06 15:00:17",
                        "last_updated_uts": 1657119617,
                        "type": "text",
                        "HEADLINE": "Bear market delivery! Bitcoiner rejoins DoorDash to buy more BTC",
                        "BODY": "<p>What did you do in the 2022 bear market, anon? For one Bitcoiner, the opportunity to take on a second job to &ldquo;stack sats&rdquo; (buy more <span pair_ID=\"1057391\">Bitcoin</span> (BTC)), was too great. Isaiah, the founder of the Cleveland Bitcoin Meetup, is delivering food to Ohio residents to earn cash on the side.</p>\n<p>Isaiah told Cointelegraph &ldquo;I joined DoorDash 2 years ago. But I only recently started doing it again once the price fell into the 20[K]s.&rdquo; DoorDash is an American food delivery service (similar to Glovo or Deliveroo), where riders pick up food from restaurants to take to people&rsquo;s homes. </p>\nThe Bitcoin price is under the 200wSMA (blue line) and has been since the 13th June. Source: Trading View <p><a href=\"https://cointelegraph.com/news/bear-market-delivery-ohio-guy-rejoins-doordash-to-buy-more-bitcoin\" target=\"_blank\" rel=\"nofollow\">Continue Reading on Coin Telegraph</a></p><span id=\"197.47.52.213\"> </span>",
                        "news_link": "https://www.investing.com/news/cryptocurrency-news/bear-market-delivery-bitcoiner-rejoins-doordash-to-buy-more-btc-2844549",
                        "third_party_url": "",
                        "related_image": "https://i-invdn-com.investing.com/news/external-images-thumbnails/pic1163faf2492507c0bd6e81e75d3f560d.jpg",
                        "related_image_big": "https://d1-invdn-com.investing.com/content/pic1163faf2492507c0bd6e81e75d3f560d.jpg",
                        "vid_filename": "",
                        "comments_cnt": "0",
                        "is_partial": "no",
                        "itemType": "hosted",
                        "news_type": "AkapiAdmin"
                    },
                    {
                        "news_ID": 2844474,
                        "hash": "e06dd2d44992b97b254e611c8318a269",
                        "providerId": "43",
                        "itemCategoryTags": "301",
                        "news_provider_name": "Cointelegraph",
                        "last_updated": "2022-07-06 12:40:27",
                        "last_updated_uts": 1657111227,
                        "type": "text",
                        "HEADLINE": "ARK Invest 'neutral to positive' on Bitcoin price as analysts await capitulation",
                        "BODY": "<p><span pair_ID=\"1057391\">Bitcoin</span> (BTC) has a &ldquo;neutral to positive&rdquo; outlook despite staying below $20,000, according to ARK Investment Management.</p>\n<p>In its latest \"Bitcoin Monthly\" report, the American asset management giant flagged signs that BTC price action is close to bottoming.</p>\n<span pair_ID=\"945629\">BTC/USD</span> 1-week candle chart (Bitstamp) with 200MA. Source: TradingView<p><a href=\"https://cointelegraph.com/news/ark-invest-neutral-to-positive-on-bitcoin-price-as-analysts-await-capitulation\" target=\"_blank\" rel=\"nofollow\">Continue Reading on Coin Telegraph</a></p><span id=\"197.47.52.213\"> </span>",
                        "news_link": "https://www.investing.com/news/cryptocurrency-news/ark-invest-neutral-to-positive-on-bitcoin-price-as-analysts-await-capitulation-2844474",
                        "third_party_url": "",
                        "related_image": "https://i-invdn-com.investing.com/news/external-images-thumbnails/pice4e7123a9cf8375e9fc405a2fb0c8ecd.jpg",
                        "related_image_big": "https://d1-invdn-com.investing.com/content/pice4e7123a9cf8375e9fc405a2fb0c8ecd.jpg",
                        "vid_filename": "",
                        "comments_cnt": "0",
                        "is_partial": "no",
                        "itemType": "hosted",
                        "news_type": "AkapiAdmin"
                    },
                    {
                        "news_ID": 2844468,
                        "hash": "e0c53a38449381fc3d72bf64181274c5",
                        "providerId": "73",
                        "itemCategoryTags": "301",
                        "news_provider_name": "CoinQuora",
                        "last_updated": "2022-07-06 12:30:40",
                        "last_updated_uts": 1657110640,
                        "type": "text",
                        "HEADLINE": "LTC, BUSD, CRV, CVX, and SRM See Increase in Accumulation",
                        "BODY": "",
                        "news_link": "https://www.investing.com/news/cryptocurrency-news/ltc-busd-crv-cvx-and-srm-see-increase-in-accumulation-2844468",
                        "third_party_url": "",
                        "related_image": "https://i-invdn-com.investing.com/news/litecoin_150x108_S_1556445302.jpg",
                        "related_image_big": "https://i-invdn-com.investing.com/news/litecoin_800x533_L_1556445302.jpg",
                        "vid_filename": "",
                        "comments_cnt": "0",
                        "is_partial": "yes",
                        "itemType": "hosted",
                        "news_type": "AkapiAdmin"
                    },
                    {
                        "news_ID": 2844459,
                        "hash": "e975f0d4040cb9595c88e17a33003e95",
                        "providerId": "73",
                        "itemCategoryTags": "301",
                        "news_provider_name": "CoinQuora",
                        "last_updated": "2022-07-06 12:00:35",
                        "last_updated_uts": 1657108835,
                        "type": "text",
                        "HEADLINE": "Minima Blockchain Now Boasts More Nodes Than Bitcoin",
                        "BODY": "",
                        "news_link": "https://www.investing.com/news/cryptocurrency-news/minima-blockchain-now-boasts-more-nodes-than-bitcoin-2844459",
                        "third_party_url": "",
                        "related_image": "https://i-invdn-com.investing.com/news/moved_small-LYNXMPEI5D0A7_L.jpg",
                        "related_image_big": "https://i-invdn-com.investing.com/news/moved_LYNXMPEI5D0A7_L.jpg",
                        "vid_filename": "",
                        "comments_cnt": "0",
                        "is_partial": "yes",
                        "itemType": "hosted",
                        "news_type": "AkapiAdmin"
                    },
                    {
                        "news_ID": 2844439,
                        "hash": "7dfaa6cec055138ece1c47913a7edfc7",
                        "providerId": "74",
                        "itemCategoryTags": "301",
                        "news_provider_name": "DailyCoin",
                        "last_updated": "2022-07-06 11:30:56",
                        "last_updated_uts": 1657107056,
                        "type": "text",
                        "HEADLINE": "Crack the Vauld: Nexo Offers to Buy Out Struggling Crypto Platform",
                        "BODY": "",
                        "news_link": "https://www.investing.com/news/cryptocurrency-news/crack-the-vauld-nexo-offers-to-buy-out-struggling-crypto-platform-2844439",
                        "third_party_url": "",
                        "related_image": "https://i-invdn-com.investing.com/news/external-images-thumbnails/pice56068e25358524c8ab8218d4faef6c6.jpg",
                        "related_image_big": "https://d1-invdn-com.investing.com/content/pice56068e25358524c8ab8218d4faef6c6.jpg",
                        "vid_filename": "",
                        "comments_cnt": "0",
                        "is_partial": "yes",
                        "itemType": "hosted",
                        "news_type": "AkapiAdmin"
                    },
                    {
                        "news_ID": 2844438,
                        "hash": "3a024868641cbf70cbb60cf3d0ee8807",
                        "providerId": "73",
                        "itemCategoryTags": "301",
                        "news_provider_name": "CoinQuora",
                        "last_updated": "2022-07-06 11:30:37",
                        "last_updated_uts": 1657107037,
                        "type": "text",
                        "HEADLINE": "Celsius Liquidation Drops to $2,722 in Light of New Loan Repayment",
                        "BODY": "",
                        "news_link": "https://www.investing.com/news/cryptocurrency-news/celsius-liquidation-drops-to-2722-in-light-of-new-loan-repayment-2844438",
                        "third_party_url": "",
                        "related_image": "https://i-invdn-com.investing.com/news/cedb56c793cebdd4180320ed33651e41_S.jpg",
                        "related_image_big": "https://i-invdn-com.investing.com/news/cedb56c793cebdd4180320ed33651e41_L.jpg",
                        "vid_filename": "",
                        "comments_cnt": "0",
                        "is_partial": "yes",
                        "itemType": "hosted",
                        "news_type": "AkapiAdmin"
                    },
                    {
                        "news_ID": 2844413,
                        "hash": "dffa7a57d7507932bb429e595d27456e",
                        "providerId": "10",
                        "itemCategoryTags": "14",
                        "news_provider_name": "Investing.com",
                        "last_updated": "2022-07-06 10:32:41",
                        "last_updated_uts": 1657103561,
                        "type": "text",
                        "HEADLINE": "Fed Minutes, Johnson Jeopardy, Amazon Grubhub Stake - What's Moving Markets",
                        "BODY": "",
                        "news_link": "https://www.investing.com/news/economy/fed-minutes-johnson-jeopardy-amazon-grubhub-stake--whats-moving-markets-2844413",
                        "third_party_url": "",
                        "related_image": "https://i-invdn-com.investing.com/news/moved_small-LYNXNPEI4H0KN_L.jpg",
                        "related_image_big": "https://i-invdn-com.investing.com/news/moved_LYNXNPEI4H0KN_L.jpg",
                        "vid_filename": "",
                        "comments_cnt": "6",
                        "is_partial": "yes",
                        "itemType": "written",
                        "news_type": "AkapiAdmin"
                    },
                    {
                        "news_ID": 2844397,
                        "hash": "020ec7f3bba3ac89fb20824ae3f75277",
                        "providerId": "74",
                        "itemCategoryTags": "301",
                        "news_provider_name": "DailyCoin",
                        "last_updated": "2022-07-06 10:00:46",
                        "last_updated_uts": 1657101646,
                        "type": "text",
                        "HEADLINE": "The Cases of Celsius, BlockFi, Voyager Shows Why Self-Sovereignty Should Be taken Seriously",
                        "BODY": "",
                        "news_link": "https://www.investing.com/news/cryptocurrency-news/the-cases-of-celsius-blockfi-voyager-shows-why-selfsovereignty-should-be-taken-seriously-2844397",
                        "third_party_url": "",
                        "related_image": "https://i-invdn-com.investing.com/news/external-images-thumbnails/picc58b680b3018230fcea8fea0504c1658.jpg",
                        "related_image_big": "https://d1-invdn-com.investing.com/content/picc58b680b3018230fcea8fea0504c1658.jpg",
                        "vid_filename": "",
                        "comments_cnt": "0",
                        "is_partial": "yes",
                        "itemType": "hosted",
                        "news_type": "AkapiAdmin"
                    }
                ]
            },
            "screen_layout": "[L2],[L2],[L2],[L2],[L2],{[L2],[L2],[L2],[L2],[P100],[L2],[L2],[L2],[L2],[L2]}*"
        }
    ]
}

我創建了以下模型類，以映射我要存儲的變量以及接下來的業務邏輯配置類。

模型類

package com.andrekreou.iot.bitpay.model;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import org.hibernate.annotations.CreationTimestamp;

import javax.persistence.*;
import java.time.LocalDateTime;

//This class is responsible for mapping the key variables from
//the JSON array to be imported. The name keys from JSON have
//to be exactly the same as here, in order for data to be fetched.


//Don't forget to apply Lombok, at the end of the project as appendix!!!
@Entity
@Table
@JsonIgnoreProperties(ignoreUnknown = true)
public class BitPayRates {
    @Id
    @SequenceGenerator(
            name = "bitpay_sequence",
            sequenceName = "bitpay_sequence",
            allocationSize = 1
            )
    @GeneratedValue(
            strategy = GenerationType.SEQUENCE,
            generator = "bitpay_sequence"
    )
    private Integer news_id;
    private String news_provider_name;
    private String HEADLINE;
    private String news_link;
    private String related_image;


    @CreationTimestamp
    private java.time.LocalDateTime timestamp;

    protected BitPayRates() {
    }

    public BitPayRates(Integer news_id,
                       String news_provider_name,
                       String HEADLINE,
                       String news_link,
                       String related_image,
                       LocalDateTime timestamp) {
        this.news_id = news_id;
        this.news_provider_name = news_provider_name;
        this.HEADLINE = HEADLINE;
        this.news_link = news_link;
        this.related_image = related_image;
        this.timestamp = timestamp;
    }

    public Integer getNews_id() {
        return news_id;
    }

    public void setNews_id(Integer news_id) {
        this.news_id = news_id;
    }

    public String getNews_provider_name() {
        return news_provider_name;
    }

    public void setNews_provider_name(String news_provider_name) {
        this.news_provider_name = news_provider_name;
    }

    public String getHEADLINE() {
        return HEADLINE;
    }

    public void setHEADLINE(String HEADLINE) {
        this.HEADLINE = HEADLINE;
    }

    public String getNews_link() {
        return news_link;
    }

    public void setNews_link(String news_link) {
        this.news_link = news_link;
    }

    public String getRelated_image() {
        return related_image;
    }

    public void setRelated_image(String related_image) {
        this.related_image = related_image;
    }

    public LocalDateTime getTimestamp() {
        return timestamp;
    }

    public void setTimestamp(LocalDateTime timestamp) {
        this.timestamp = timestamp;
    }

    @Override
    public String toString() {
        return "BitPayRates{" +
                "news_id=" + news_id +
                ", news_provider_name='" + news_provider_name + '\'' +
                ", HEADLINE='" + HEADLINE + '\'' +
                ", news_link='" + news_link + '\'' +
                ", related_image='" + related_image + '\'' +
                ", timestamp=" + timestamp +
                '}';
    }
}

配置類

package com.andrekreou.iot.bitpay.configuration;

import com.andrekreou.iot.bitpay.model.BitPayRates;
import com.andrekreou.iot.bitpay.repository.BitPayRatesRepo;
import org.springframework.boot.CommandLineRunner;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.*;
import org.springframework.web.client.RestTemplate;

import java.util.Collections;
import java.util.List;

//The configuration class to fetch data from url and execute the insertion
//of the data into the PostgreSQL database
@Configuration

public class BitPayRatesConfig {

    @Bean
    CommandLineRunner commandLineRunner(BitPayRatesRepo bitPayRatesRepo){
        return args -> {
            String url = "https://investing-cryptocurrency-markets.p.rapidapi.com/coins/get-news?pair_ID=1057391";
            RestTemplate restTemplate = new RestTemplate();

            HttpHeaders headers = new HttpHeaders();
            headers.setContentType(MediaType.APPLICATION_JSON);
            headers.setAccept(Collections.singletonList(MediaType.APPLICATION_JSON));
            headers.set("X-RapidAPI-Key","605a619252msh709d3d6fa6fbdcdp155ef4jsn6cd36a1a4195");
            headers.set("X-RapidAPI-Host","investing-cryptocurrency-markets.p.rapidapi.com");

            HttpEntity<Object> request = new HttpEntity<>(headers);

            ResponseEntity<List<BitPayRates>> postEntity = restTemplate.exchange(
                    url,
                    HttpMethod.GET,
                    request,
                    new ParameterizedTypeReference<>() {
                    });

            List<BitPayRates> results = postEntity.getBody();
            bitPayRatesRepo.saveAll(results);
            System.out.println(results);
        };
    }
}

我收到以下錯誤，我對如何解決它有點困惑。 有什么建議？？？

堆棧跟蹤

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-07-06 20:48:38.171 ERROR 4160 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalStateException: Failed to execute CommandLineRunner
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:774) ~[spring-boot-2.7.0.jar:2.7.0]
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:755) ~[spring-boot-2.7.0.jar:2.7.0]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.7.0.jar:2.7.0]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1306) ~[spring-boot-2.7.0.jar:2.7.0]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1295) ~[spring-boot-2.7.0.jar:2.7.0]
    at com.andrekreou.iot.IotApplication.main(IotApplication.java:12) ~[classes/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) ~[spring-boot-devtools-2.7.0.jar:2.7.0]
Caused by: org.springframework.web.client.RestClientException: Error while extracting response for type [java.util.List<com.andrekreou.iot.bitpay.model.BitPayRates>] and content type [application/json]; nested exception is org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot deserialize value of type `java.util.ArrayList<com.andrekreou.iot.bitpay.model.BitPayRates>` from Object value (token `JsonToken.START_OBJECT`); nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.util.ArrayList<com.andrekreou.iot.bitpay.model.BitPayRates>` from Object value (token `JsonToken.START_OBJECT`)
 at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 1, column: 1]
    at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:120) ~[spring-web-5.3.20.jar:5.3.20]
    at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:1037) ~[spring-web-5.3.20.jar:5.3.20]
    at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:1020) ~[spring-web-5.3.20.jar:5.3.20]
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:778) ~[spring-web-5.3.20.jar:5.3.20]
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:711) ~[spring-web-5.3.20.jar:5.3.20]
    at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:631) ~[spring-web-5.3.20.jar:5.3.20]
    at com.andrekreou.iot.bitpay.configuration.BitPayRatesConfig.lambda$commandLineRunner$0(BitPayRatesConfig.java:35) ~[classes/:na]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:771) ~[spring-boot-2.7.0.jar:2.7.0]
    ... 10 common frames omitted
Caused by: org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot deserialize value of type `java.util.ArrayList<com.andrekreou.iot.bitpay.model.BitPayRates>` from Object value (token `JsonToken.START_OBJECT`); nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.util.ArrayList<com.andrekreou.iot.bitpay.model.BitPayRates>` from Object value (token `JsonToken.START_OBJECT`)
 at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 1, column: 1]
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:391) ~[spring-web-5.3.20.jar:5.3.20]
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:343) ~[spring-web-5.3.20.jar:5.3.20]
    at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:105) ~[spring-web-5.3.20.jar:5.3.20]
    ... 17 common frames omitted
Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.util.ArrayList<com.andrekreou.iot.bitpay.model.BitPayRates>` from Object value (token `JsonToken.START_OBJECT`)
 at [Source: (org.springframework.util.StreamUtils$NonClosingInputStream); line: 1, column: 1]
    at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:59) ~[jackson-databind-2.13.3.jar:2.13.3]
    at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1741) ~[jackson-databind-2.13.3.jar:2.13.3]
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1515) ~[jackson-databind-2.13.3.jar:2.13.3]
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1462) ~[jackson-databind-2.13.3.jar:2.13.3]
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.handleNonArray(CollectionDeserializer.java:392) ~[jackson-databind-2.13.3.jar:2.13.3]
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:252) ~[jackson-databind-2.13.3.jar:2.13.3]
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:28) ~[jackson-databind-2.13.3.jar:2.13.3]
    at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:323) ~[jackson-databind-2.13.3.jar:2.13.3]
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4674) ~[jackson-databind-2.13.3.jar:2.13.3]
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3682) ~[jackson-databind-2.13.3.jar:2.13.3]
    at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:380) ~[spring-web-5.3.20.jar:5.3.20]
    ... 19 common frames omitted

2022-07-06 20:48:38.171  INFO 4160 --- [  restartedMain] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'
2022-07-06 20:48:38.186  INFO 4160 --- [  restartedMain] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2022-07-06 20:48:38.186  INFO 4160 --- [  restartedMain] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.

Process finished with exit code 0

Answer 1

問題是您正試圖將您的響應反序列化為數組：

 ResponseEntity<List<BitPayRates>> postEntity = restTemplate.exchange(
                    url,
                    HttpMethod.GET,
                    request,
                    new ParameterizedTypeReference<>() {
                    });

但是你得到一個對象作為響應（注意花括號）：

  {
        "data": [
           ...

 "screen_data": `{`
            "ob": "Yes",
            "next_page": 2,
            "news": [
     ]
    }


    ...


 }

所以你需要創建一個類來代表你想要反序列化的 JSON，或者你可以做這樣的事情：

ResponseEntity<String> postEntity = restTemplate.exchange(
                    url,
                    HttpMethod.GET,
                    request,
                    String.class)


    List<BitPayRates> bitPayRatesList = new ArrayList<>();
    ObjectMapper mapper = new ObjectMapper();
    JsonNode actualObj = mapper.readTree(postEntity.getBody());
    JsonNode node = actualObj.get("data");
    if (node.isArray()) {
        for (final JsonNode objNode : node) {
            JsonNode screenDataNode = objNode.get("screen_data");
            JsonNode newsNode = screenDataNode.get("news");
            for(JsonNode news : newsNode){
                BitPayRates newJsonNode = mapper.treeToValue(news, BitPayRates.class);
                bitPayRatesList.add(newJsonNode);
            }

        }
    }

Answer 2

您需要創建與響應 json 匹配的新模型類。 模型類可以很容易地在線生成。 你可以在這里做。 將這些模型類復制粘貼到您的項目中，並在您的響應中使用父類。 考慮您的父類是Root 。 然后在你的 commandLineRunner 休息后，把下面的邏輯

Root response = postEntity.getBody();
//either manually map response to BitPayRates or use some mapping framework like https://mapstruct.org/
bitPayRatesRepo.saveAll(results);//save mapped result to database