java - Spring RestTemplate Jackson 反序列化数组数组

Question

我使用 Spring RestTemplate 从 API 中提取数据，该 API 返回以下格式的未命名数组:

[
    [
        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
    ]
]

嵌套数组中的索引代表 Candlestick 的以下属性:

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

例如，在第一个嵌套数组中，蜡烛图的时间为 1518230040，最低价为 8863.96，最高价为 8876.95 ，开盘价为 8863.96，收盘价为 8876.94，成交量为 1.81986441。

我想将这些嵌套数组元素映射到 Candlestick 对象。下面是我的 Candlestick 类。

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 将嵌套数组映射到 Candlestick 对象？

Answer 1

您需要执行以下操作；

1. 为 Candlestick pojo 配置编写自定义反序列化器

   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 使用自定义反序列化器

   // 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);