Spring RestTemplate Jackson 反序列化數組數組

Question

我正在使用 Spring RestTemplate 從 API 中提取數據，該 API 以以下格式返回未命名的數組數組：

[
    [
        1518230040,
        8863.96,
        8876.95,
        8863.96,
        8876.94,
        1.81986441
    ],
    [
        1518229980,
        8851.03,
        8862.53,
        8853.79,
        8862.53,
        2.95533163
    ],
    [
        1518229920,
        8853.79,
        8855.3,
        8855.29,
        8853.8,
        3.0015851299999996
    ]
]

嵌套數組中的索引代表Candlestick的以下屬性：

0 => time
1 => low
2 => high
3 => open
4 => close
5 => volume

例如，在第一個嵌套數組中，燭台的時間為 1518230040，最低價為 8863.96，最高價為 8876.95，開盤價為 8863.96，收盤價為 8876.94，成交量為 1.81986441。

我想將這些嵌套的數組元素映射到 Candlestick 對象。 下面是我的燭台課。

import java.math.BigDecimal;

public class Candlestick {
    private long time;

    private BigDecimal low;

    private BigDecimal high;

    private BigDecimal open;

    private BigDecimal close;

    private BigDecimal volume;

    public long getTime() {
        return time;
    }

    public void setTime(long time) {
        this.time = time;
    }

    public BigDecimal getLow() {
        return low;
    }

    public void setLow(BigDecimal low) {
        this.low = low;
    }

    public BigDecimal getHigh() {
        return high;
    }

    public void setHigh(BigDecimal high) {
        this.high = high;
    }

    public BigDecimal getOpen() {
        return open;
    }

    public void setOpen(BigDecimal open) {
        this.open = open;
    }

    public BigDecimal getClose() {
        return close;
    }

    public void setClose(BigDecimal close) {
        this.close = close;
    }

    public BigDecimal getVolume() {
        return volume;
    }

    public void setVolume(BigDecimal volume) {
        this.volume = volume;
    }

    @Override
    public String toString() {
        return "Candle [time=" + time + ", low=" + low + ", high=" + high + ", open=" + open + ", close=" + close
                + ", volume=" + volume + "]";
    }
}

如何使用 Spring RestTemplate 和 Jackson 將嵌套數組映射到 Candlestick 對象？

Answer 1

您需要執行以下操作；

1. 為 Candlestick pojo 配置編寫自定義解串器

   public class CandlestickDeserializer extends StdDeserializer<Candlestick> { public CandlestickDeserializer() { this(null); } public CandlestickDeserializer(Class<?> vc) { super(vc); } @Override public Item deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException { JsonNode node = jp.getCodec().readTree(jp); // Read the Array or Arrays return new Candlestick(// Return with correct values read from Array); } }

2. ObjectMapper 使用該自定義反序列化器

   // This will get the Spring ObjectMapper singleton instance. @Autowired ObjectMapper mapper; @PostConstruct public void init() throws Exception { SimpleModule module = new SimpleModule(); module.addDeserializer(Candlestick.class, new CandlestickDeserializer()); mapper.registerModule(module); } Candlestick readValue = mapper.readValue(json, Candlestick.class);

Answer 2

設計自定義解串器將是解決此問題的合理解決方案。 但是將數組映射到對象似乎是一項棘手的工作。 以@shazin 的想法為基礎，將數組數組映射到對象列表的自定義反序列化器可以寫成如下：

public class CStickListDeserializer extends StdDeserializer<ArrayList<Candlestick>> { 

    public CStickListDeserializer() { 
        this(null); 
    } 

    public CStickListDeserializer(Class<?> c) { 
        super(c); 
    }

    @Override
    public ArrayList<Candlestick> deserialize(JsonParser jp, DeserializationContext ctxt) 
      throws IOException, JsonProcessingException {

        Candlestick cs ;
        ArrayList<Candlestick> cList = new ArrayList<Candlestick>();
        BigDecimal[][] a = jp.readValueAs(BigDecimal[][].class);
        for(BigDecimal[] a1 : a){
            cs = new Candlestick();
            cs.setTime(a1[0].longValue());
            cs.setLow(a1[1]);
            cs.setHigh(a1[2]);
            cs.setOpen(a1[3]);
            cs.setClose(a1[4]);
            cs.setVolume(a1[5]); 
            cList.add(cs);
        }
             return cList;
    }
}

用法：

     ObjectMapper om = new ObjectMapper();
     SimpleModule mod = new SimpleModule();
     mod.addDeserializer(ArrayList.class, new CStickListDeserializer());
     om.registerModule(mod);
     ArrayList<Candlestick> CandlestickList = om.readValue(json, ArrayList.class);