java resultset to json code example

Example 1: java serialize object to json

public class someClass {
//your lcode and logic...
ObjectMapper mapper = new ObjectMapper();
SimpleModule module = new SimpleModule();
module.addSerializer(MyAwesomeClass.class, new MyAwesomeSerializer());
mapper.registerModule(module);

jsonNode = mapper.convertValue(myAwesomeObject, JsonNode.class);
//... your code and logic
}
  
public class MyAwesomeSerializer extends StdSerializer<MyAwesomeClass> {

    public MyAwesomeSerializer() {
        super(MyAwesomeClass.class);
    }

    @Override
    public void serialize(MyAwesomeClass myAwesomeClass, JsonGenerator jgen, SerializerProvider provider) throws IOException {
        ObjectMapper mapper = new ObjectMapper();

        jgen.writeStartObject();
        jgen.writeStringField("name", myAwesomeClass.getName());
        jgen.writeStringField("age", myAwesomeClass.getAge());

          jgen.writeArrayFieldStart("hobbies");
          for (Hobby hobby : myAwesomeClass.getHobbies()) {
              jgen.writeObject(mapper.convertValue(hobby, JsonNode.class));
          }
          jgen.writeEndArray();
      
        jgen.writeEndObject();
    }

}

Example 2: convert java object to json

Jackson Data-bind depdendency that take care of 
Converting between 
JSON to Java Object 
and 
Java Object to JSON

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.12.0</version>
</dependency>