Map turn json format retention solutions null values

Map turn json format preserves null solution value

Encountered in the development of the map data transfer json format, and then map contains null key-value pairs are not transferred, so record it, the following is a workaround

Use fastJson conversion

import com.alibaba.fastjson.JSON

Map<String, Object> map = new HashMap<String, Object>();

String toJSON = JSON.toJSONString(map, SerializerFeature.WRITE_MAP_NULL_FEATURES, SerializerFeature.QuoteFieldNames);

 

The first is WRITE_MAP_NULL_FEATURES showing: retention map median null key-value pairs,

The second is QuoteFieldNames said: output key whether to use double quotes ( "" ) will be key all wrapped up , the default is true

 

About SerializerFeature property (more commonly used include)

Name Meaning

QuoteFieldNames output key whether to use double quotation marks , the default is true

QuoteFieldNames output key whether to use double quotation marks , the default is true

WriteMapNullValue whether the output value is null field , the default is false

WriteNullNumberAsZero numeric field if it is null, the output is 0, not null

WriteNullListAsEmpty List field if it is null, the output is [], not null

WriteNullStringAsEmpty character type field if it is null, the output is "", rather than null

WriteNullBooleanAsFalse Boolean field if it is null, the output false, rather than null