How to modify JsonNode in Java

Question

I need to change a JSON attribute s value in Java  I can get the value properly but I couldn t modify the JSON   here is the code below     JsonNode blablas   mapper readTree parser  get  blablas        for  JsonNode jsonNode   blablas            String elementId   jsonNode get  element   asText            String value   jsonNode get  value   asText            if  StringUtils equalsIgnoreCase elementId   blabla                  if value    null  amp  amp  value equals  YES                         I need to change the node to NO then save it into the JSON                                 What is the best way to do this

User · Answer

Just for the sake of understanding of others who may not get the whole picture clear following code works for me to find a field and then update it  ObjectMapper mapper   new ObjectMapper    JsonNode rootNode   mapper readTree JsonString       JsonPointer valueNodePointer   JsonPointer compile   GrandObj Obj field    JsonPointer containerPointer   valueNodePointer head    JsonNode parentJsonNode   rootNode at containerPointer    if   parentJsonNode isMissingNode    amp  amp  parentJsonNode isObject          ObjectNode parentObjectNode    ObjectNode  parentJsonNode        following will give you just the field name         e g  if pointer is  grandObject Object field       JsonPoint last   will give you  field        remember to take out the   character      String fieldName   valueNodePointer last   toString        fieldName   fieldName replace Character toString JsonPointer SEPARATOR   StringUtils EMPTY       JsonNode fieldValueNode   parentObjectNode get fieldName        if fieldValueNode    null            parentObjectNode put fieldName   NewValue

User · Answer

Adding an answer as some others have upvoted in the comments of the accepted answer they are getting this exception when attempting to cast to ObjectNode  myself included     Exception in thread  main  java lang ClassCastException   com fasterxml jackson databind node TextNode cannot be cast to com fasterxml jackson databind node ObjectNode   The solution is to get the  parent  node  and perform a put  effectively replacing the entire node  regardless of original node type    If you need to  modify  the node using the existing value of the node    get the value array of the JsonNode Perform your modification on that value array Proceed to call put on the parent    Code  where the goal is to modify subfield  which is the child node of NodeA and Node1   JsonNode nodeParent   someNode get  NodeA                    get  Node1        Manually modify value of  subfield   can only be done using the parent    ObjectNode  nodeParent  put  subfield    my-new-value-here      Credits   I got this inspiration from here  thanks to wassgreen

User · Answer

You need to get ObjectNode type object in order to set values  Take a look at this

User · Answer

I think you can just cast to ObjectNode and use put method  Like this   ObjectNode o    ObjectNode  jsonNode  o put  value    NO

User · Answer

JsonNode is immutable and is intended for parse operation   However  it can be cast into ObjectNode  and ArrayNode  that allow mutations     ObjectNode jsonNode  put  value    NO      For an array  you can use     ObjectNode jsonNode  putArray  arrayName   add object ge  tValue

User · Answer

The  Sharon-Ben-Asher answer is ok   But in my case  for an array i have to use     ArrayNode  jsonNode  add  value

[java] How to modify JsonNode in Java?

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