java convert POST form array to JSON object or POJO or map

Question

I have POST query string with the following format:

param1=aaa&inners[0]["innerParam"]=bbb&inners[1]["innerParam"]=nnn

I need to easily convert it to a map or POJO.

public class pojo{
private String param1;

private List<OtherPojo> inners;//array is also ok

//getters etc
}

class OtherPojo{
private String innerParam.

//getters etc
}

I thought it might be done by Jersey @BeanParam or sth else, but unfortunately it's not possible. So I just have a string and need to compile it to map or pojo. Please note that it's not clear for me how to parse this construction

inners[0]["innerParam"]

I wouldn't like to do it manually. So I need to parse it desirable in one line.

Pojo p=someHelper.compileToPojo(postString);// or map

Which lib to use, if exists?

Answer 1

the library you could use is: com.fasterxml.jackson

and here how it could be implemented:

public void checkAndSetChildValues(ObjectNode node, String field, String value, ObjectMapper mapper) {
    int indexDot = field.indexOf('.');
    if (indexDot > -1) {
        String childFieldName = field.substring(0, indexDot);
        ObjectNode child = node.with(childFieldName);
        checkAndSetChildValues(child, field.substring(indexDot + 1), value, mapper);
    } else {
        try{
            node.set(field, mapper.convertValue(value, JsonNode.class));
        } catch(IllegalArgumentException ex){
            logger.debug("could not parse value {} for field {}", value, field);
        }
    }
}


public Object parse(Class type, String entityString) throws UnsupportedEncodingException {

    ObjectMapper mapper = mapperHolder.get();
    ObjectNode node = mapper.createObjectNode();
    Scanner s = new Scanner(entityString).useDelimiter("&|=");
    while (s.hasNext()) {
        String key = s.next();
        String value = s.hasNext() ? URLDecoder.decode(s.next(), "UTF-8") : null;
        checkAndSetChildValues(node, key, value, mapper);
    }
    Object result = mapper.convertValue(node, type);
    return result;
}

So you should be able to implement an own javax.ws.rs.ext.MessageBodyReadersee: https://jersey.java.net/documentation/latest/message-body-workers.html#d0e7151