Java Jackson 总是将一个类型序列化为另一个类型

Question

Is there a way to tell Jackson to always serialize one type to another. In my case I would like to always serialize Long to String. Right now whenever there is an object with a Long property we have to annotate it with @JsonSerialize(using=ToStringSerializer.class) . This is tedious and easy to forget.

I would like to be able to configure the Jackson object mapper to always convert Long to String in the spring boot bean creation.

Answer 1

IMHO, multiple options are there.

I

com.fasterxml.jackson.databind.ser.std.StdSerializer implementation that can be set to your ObjectMapper in the spring context.

    @Bean
    public Jackson2ObjectMapperBuilder objectMapperBuilder() {
        Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
        ....
        builder.serializerByType(<type>, <your custom serializer>);
        return builder;
    }

As for the custom serializer, you can extend the above-mentioned class StdSerializer .

II

spring.jackson.generator.write-numbers-as-strings=true

Note

Be aware of that Feature.WRITE_NUMBERS_AS_STRINGS has deprecated Since 2.10 of jackson version.

I hope it helps.

Answer 2

This can be done using this serialization feature.

jsonGenerator.configure(Feature.WRITE_NUMBERS_AS_STRINGS,true);

http://fasterxml.github.io/jackson-core/javadoc/2.10/com/fasterxml/jackson/core/json/JsonWriteFeature.html#WRITE_NUMBERS_AS_STRINGS