Question

I am having trouble with this json.

{"directory": {
         "employees": {"employee": [
             {
                 "field": [
                     {
                         "content": "Charlotte Abbott",
                         "id": "displayName"
                     },
                     {
                         "content": "Charlotte",
                         "id": "firstName"
                     },

I am casting it into a class that looks like this

@SerializedName("directory")
    public Directory directory;

    public class Directory
    {
        @SerializedName("employees")
        public Employees employees;
    }
    public class Employees
    {
        @SerializedName("employee")
        public List<Employee> employee;
    }

    public class Employee
    {
        @SerializedName("field")
        public List<Fields> fields;

        @SerializedName("id")
        public String employeeId;
    }
    public class Fields
    {
        @SerializedName("content")
        public String content;

        @SerializedName("id")
        public String label;
    }

And it is not reaching all the variables to insert the data when it serializes. Instead I am getting all nulls. I am however getting the right amount (number) of Directory objects so I know it is reaching that far. Anyone have some insight on what I am doing wrong here? The json is the way it is, I didn’t design it, but it is how it is used.

Answer 1

Quite a weird data structure you have to work with, but here is it.

public class App {
    public static void main(String[] args) {
        Gson gson = new Gson();
        String jsonString = "{\"directory\": {\"employees\": {\"employee\": [{\"field\": [{\"content\": \"Charlotte Abbott\",\"id\": \"displayName\"},{\"content\": \"Charlotte\",\"id\": \"firstName\"}]}]}}}";

        Wrapper obj = (Wrapper) gson.fromJson(jsonString, Wrapper.class);

        System.out.println(obj.getDirectory().getEmployees().getEmployeeList()
                .get(0).getFieldList().get(0).getContent());
    }
}

You need a Wrapper class to wrap around Directory.

public class Wrapper {
    private Directory directory;

    public Directory getDirectory() {
        return directory;
    }

    public void setDirectory(Directory directory) {
        this.directory = directory;
    }
}

Directory class.

public class Directory {
    @SerializedName("employees")
    private Employees employees;

    public Employees getEmployees() {
        return employees;
    }

    public void setEmployees(Employees employees) {
        this.employees = employees;
    }
}

Employees class:

public class Employees {
    @SerializedName("employee")
    private List<Employee> employeeList;

    public List<Employee> getEmployeeList() {
        return employeeList;
    }

    public void setEmployeeList(List<Employee> employeeList) {
        this.employeeList = employeeList;
    }
}

Employee class:

public class Employee {
    @SerializedName("field")
    private List<Field> fieldList;

    public List<Field> getFieldList() {
        return fieldList;
    }

    public void setFieldList(List<Field> fieldList) {
        this.fieldList = fieldList;
    }
}

Field class:

public class Field {
    @SerializedName("content")
    private String content;
    @SerializedName("id")
    private String id;

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }
}

See a JSON to Java Object using GSON example here: http://java.sg/parsing-a-json-string-into-an-object-with-gson-easily/