@GET
@Produces("application/json")
@Path("/list")
public String getList(){
    List<Person> persons = new ArrayList<>();
    persons.add(new Person("1","2"));
    persons.add(new Person("3","4"));
    persons.add(new Person("5","6"));
    // takes advantage to toString() implementation to format as [a,b,c]
    return persons.toString();
}

POJO课程：

@XmlRootElement
public class Person {
    @XmlElement(name="fn")
    String fn;

    @XmlElement(name="ln")
    String ln;

    public Person(){        
    }

    public Person(String fn,String ln) {
        this.fn = fn;
        this.ln = ln;
    }    

    @Override
    public String toString(){
        try {
            // takes advantage of toString() implementation to format {"a":"b"}
            return new JSONObject().put("fn",fn).put("ln",ln).toString();
        } catch (JSONException e) {
            return null;
        }
    }
}

结果如下：

[{"fn":"1","ln":"2"},{"fn":"3","ln":"4"},{"fn":"5","ln":"6"}]