Jackson自定义全局范围类型解析

有个业务需要自定义类型序列化器。OracleTimeSerializer

/**
 * @ClassName OracleTimeSerializer
 * @Description
 * @Author LiuQian
 * @Date 2022-11-13
 **/
@JacksonStdImpl
public class OracleTimeSerializer extends StdScalarSerializer<TIMESTAMP> {

    public OracleTimeSerializer() {
        super(TIMESTAMP.class);
    }


    @Override
    public void serialize(TIMESTAMP timestamp, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
        try {
            jsonGenerator.writeObject(timestamp.timestampValue());
        } catch (SQLException throwables) {
            throwables.printStackTrace();
            jsonGenerator.writeString(timestamp.toString());
        }
    }

    @Override
    public JsonNode getSchema(SerializerProvider provider, Type typeHint) {
        return this.createSchemaNode("string", true);
    }

    @Override
    public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint) throws JsonMappingException {
        this.visitStringFormat(visitor, typeHint, JsonValueFormat.DATE_TIME);
    }
}

使用方式有两种.

• 1.在全局ObjectMapper中使用SimpleModule

/**
     * 创建Jackson对象映射器
     *
     * @param builder Jackson对象映射器构建器
     * @return
     */
    @Bean
    public ObjectMapper getJacksonObjectMapper(Jackson2ObjectMapperBuilder builder) {
        ObjectMapper objectMapper = builder.createXmlMapper(false).build();
        //序列换成json时,将所有的long变成string.因为js中得数字类型不能包含所有的java long值，超过16位后会出现精度丢失
        SimpleModule simpleModule = new SimpleModule();
        simpleModule.addSerializer(Long.class, com.fasterxml.jackson.databind.ser.std.ToStringSerializer.instance);
        simpleModule.addSerializer(Long.TYPE, com.fasterxml.jackson.databind.ser.std.ToStringSerializer.instance);
        simpleModule.addSerializer(TIMESTAMP.class, new OracleTimeSerializer());
        objectMapper.registerModule(simpleModule);
        //反序列化的时候如果多了其他属性,不抛出异常
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        //日期格式处理
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
        return objectMapper;
    }

• 2.在Bean中指定通过注释实现序列化器的注册

@JsonSerialize(using = OracleTimeSerializer.class)
public class Item {
    ...
}