JSON Array to Java List objects

https://github.com/FasterXML/jackson

In one of my project, I had to map the JSON string to Java objects. Mapping a simple POJO was not a problem. Mapping a list of String also not a problem. But I had to map a list of Java object.

I had to spend many hours of searching; couldn't find a simple answer.

Then, finally I found out; it was a simple add method. I had to add the Java object into that list.
Here is the list of various components:

incoming JSON:

 {
   "title": "software developer",
   "description": "good developer at some company",
   "keywords":["java", "soa", "bigdata"],
   "educationList":  [{
                              "course": "Bachelor of Science",
                               "institution":  "Madras University",
                               "startYear": "1979",
                                "endYear": "1982"
                          } ,

                          {
                              "course": "Master of Science",
                               "institution":  "Stanford University",
                               "startYear": "1989",
                               "endYear": "1993"
                          }
                    ]
 
}

POJO:

public class SeedProfile {
    private String title;
    private String description;
    private List<String> keywords;
    private List<EducationObject> educationList = new ArrayList<EducationObject>();
   
    public List<EducationObject> getEducationList() {
        return educationList;
    }

    public void setEducationList(List<EducationObject> educationList) {
        this.educationList = educationList;
    }
   
    public void addEducationObject(EducationObject educationObject){
        educationList.add(educationObject);
    }
}

servlet processing request:

            ObjectMapper mapper = new ObjectMapper();
            String incomejson = req.getParameter("incomejson");
            System.out.println(incomejson);
            SeedProfile seed = mapper.readValue(incomejson, SeedProfile.class);
          
 servlet response:

            out.println(seed.getTitle());out.println("<br/>");
            out.println(seed.getKeywords());out.println("<br/>");
            List list = seed.getEducationList();
            ListIterator it = list.listIterator();
            while(it.hasNext()){
                EducationObject edu = (EducationObject) it.next();
                out.println(edu.getInstitution());out.println("<br/>");
            }

Welcome to PlanetEarth.java

Welcome to PlanetEarth.java

Do we need to start PlanetEarth.java with Eclipse?

Perhaps not; you can just start with using a 

• Notepad - to write your java 
• javac - command to compile your java into a class
• java - command to execute the class

Using Notepad, create the PlanetEarth.java

package planet.earth.common;

/**

 * This is common to all human beings on Planet Earth.

 * 

 */

public final class PlanetEarth {

public static void main(String[] userInputs) {

System.out.println("Hello World!");

System.out.println("Hello Planet Earth!");

}

}

The term 'World' refers to political quality of the planet earth. World, country, state, citizen and so on was created for the purpose of effective management of government institutions. Earlier there were leaders as the head of these organizations. Now, instead of leaders, there are politicians. So, the world is now divided into many fragments.

The term, 'Planet Earth' unites all human beings. So, instead of saying, Hello World!, let us greet all human beings with, Hello Planet Earth!