Spring RestTemplate Jackson 反序列化数组数组

Question

我正在使用 Spring RestTemplate 从 API 中提取数据，returns 一个未命名的数组，格式如下：

[
    [
        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
    ]
]

嵌套数组中的索引表示 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，Candlestick 的 time 为 1518230040，low 为 8863.96，high是8876.95，open是8863.96，close是8876.94，volume 是 1.81986441。

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

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；

为 Candlestick pojo Configure 编写自定义解串器

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);
    }
}

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);

Answer 2

设计自定义反序列化器是解决此问题的合理方法。但是将数组映射到对象似乎是一项棘手的工作。以@shazin 的想法为基础，将数组数组映射到对象列表的自定义反序列化器可以编写如下：

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);

Spring RestTemplate Jackson 反序列化数组数组

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resttemplate