java如何获取需要在页面树形展示的json数组

一：数据库

二：java代码（eova平台）

public void tree() {
String sql = "SELECT id,name from gym_centers where pid=?";
List<Record> pros = Db.find(sql, 0);
for (int i = 0; i < pros.size(); i++) {
int id = pros.get(i).getInt("id");
String name = pros.get(i).getStr("name");
List<Record> citys = Db.find(sql, id);
List<Record> r2 = new ArrayList<Record>();
for (int j = 0; j < citys.size(); j++) {
Record r = new Record();
int cityId = citys.get(j).getInt("id");
String cityName = citys.get(j).getStr("name");
r.set("id", cityId);
r.set("name", cityName);
List<Record> gyms = Db.find(sql, cityId);
List<Record> r4 = new ArrayList<Record>();
for (int k = 0; k < gyms.size(); k++) {
Record r3 = new Record();
int gymId = gyms.get(k).getInt("id");
String gymName = gyms.get(k).getStr("name");
r3.set("id", gymId);
r3.set("name", gymName);
r4.add(k, r3);
}
r2.add(j, r);
r2.get(j).set("child", r4);
}
pros.get(i).set("child", r2);
System.err.println(pros.get(i));
}
renderJson(JsonKit.toJson(pros));
}

三：返回的结果

四：在页面显示

据说利用easyui很容易实现，我没有做。就暂时不上代码了。等以后亲自做了在来补全。