java - 如何使用 JSONObject 将长纪元日期格式序列化为日期

Question

我有 json 字符串有效负载，其日期采用纪元(长)格式。但我必须将其转换为 yyyyMMddHHmmss 格式。我正在使用自定义序列化程序，我可以将其应用于特定字段。但序列化无法应用在那个领域。

测试.java

 private static String json = "{

          "dcCountryCode": "US",
          "orderDate": 1517855400000
        }";



    @JsonSerialize(using = CustomLongSerializer.class)
    private static Long date;

    public static void main(String[] args) {


        JSONObject obj = new JSONObject(json);

        String country = obj.getString("dcCountryCode");

        date = obj.getLong("orderDate");


        System.out.println(country);

        System.out.println(date);

    }

CustomLongSerializer.java

    package com.company;

    import com.fasterxml.jackson.core.JsonGenerator;
    import com.fasterxml.jackson.databind.SerializerProvider;
    import com.fasterxml.jackson.databind.ser.std.StdSerializer;

    import java.io.IOException;
    import java.text.SimpleDateFormat;


    // This is for Custom Date serializer
    public class CustomLongSerializer extends StdSerializer<Long> {

        protected CustomLongSerializer(Class<Long> t) {
            super(t);
        }

        protected CustomLongSerializer() {
            this(Long.class);
        }

        private static final long serialVersionUID = 1L;

        @Override
        public void serialize(Long value, JsonGenerator gen, SerializerProvider provider) throws IOException {

            SimpleDateFormat df = new SimpleDateFormat("yyyyMMddHHmmss");
            gen.writeString(df.format(value));

        }

    }



Expected Out put in yyyyMMddHHmmss format.

But still returning epoch date format.

Can anyone help me with this.

Answer 1

可以通过禁用 SerializationFeature.WRITE_DATES_AS_TIMESTAMPS 并在映射器中设置 DateFormatter 来以更简单的方式实现:

public class TestDate {
    private String dcCountryCode;
    private Date date;
// getters/setters
}

// test class
String json = "{\n" +
"          \"dcCountryCode\": \"US\",\n" +
"          \"date\": 1517855400000\n" +
"        }";

ObjectMapper mapper = new ObjectMapper()
                .disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
                .setDateFormat(new SimpleDateFormat("yyyyMMddHHmmss"));

TestDate test = mapper.readValue(json, TestDate.class);

System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(test));

输出:

{
  "dcCountryCode" : "US",
  "date" : "20180205203000"
}