Samples DataBind

Fastjson full support databind, it's simple to use.

Encode

Group group = new Group();
group.setId(0L);
group.setName("admin");

User guestUser = new User();
guestUser.setId(2L);
guestUser.setName("guest");

User rootUser = new User();
rootUser.setId(3L);
rootUser.setName("root");

group.getUsers().add(guestUser);
group.getUsers().add(rootUser);

String jsonString = JSON.toJSONString(group);

System.out.println(jsonString);

Group.java

public class Group {

    private Long       id;
    private String     name;
    private List<User> users = new ArrayList<User>();

    public Long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List<User> getUsers() {
        return users;
    }

    public void setUsers(List<User> users) {
        this.users = users;
    }
}

User.java

public class User {

    private Long   id;
    private String name;

    public Long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}