如下，我们要返回下面的数据格式

 {"value": "3","label": "安徽省","children": [{"value": "安庆市","label": "36","children1s": [{"label": "398","value": "迎江区"},{"label": "399","value": "大观区"},{"label": "400","value": "宜秀区"},{"label": "401","value": "桐城市"},{"label": "402","value": "怀宁县"},{"label": "403","value": "枞阳县"},{

那么可以通过构造辅助类来完成

这里因为这里是三级，所以我就构造了三个辅助类

@Getter
@Setter
public class Data {private String value;private String label;private List<Children> children;
}

@Setter
@Getter
public class Children {private String value;private String label;private List<Children1> children1s;
}

@Getter
@Setter
public class Children1 {private String label;private String value;
}

我的mapper

  //查询所有的省@Select("select * from zone where pid = 1")List<ZoneInfo> selectProvince();//查询该省所有的市@Select("select * from zone where  pid =#{provinceId}")List<ZoneInfo> selectCityByProvinceId(String provinceId);//查询该市对应的县@Select("select * from zone where  pid =#{cityId}")List<ZoneInfo> selectCountyByCityId(String cityId);

接下来是我的serviceimpl

 @Overridepublic Result selectAll() {List<Data> dataList = null;try {dataList = new ArrayList<Data>();List<ZoneInfo> provinces = zoneInfoMapper.selectProvince();for (ZoneInfo province : provinces) {Data data = new Data();data.setValue(String.valueOf(province.getId()));data.setLabel(province.getDistrict());List<ZoneInfo> cities = zoneInfoMapper.selectCityByProvinceId(String.valueOf(province.getId()));List<Children> childrenList = new ArrayList<Children>();for (ZoneInfo city : cities) {Children children = new Children();children.setLabel(String.valueOf(city.getId()));children.setValue(city.getDistrict());childrenList.add(children);List<ZoneInfo> counties = zoneInfoMapper.selectCountyByCityId(String.valueOf(city.getId()));List<Children1> children1s = new ArrayList<Children1>();for (ZoneInfo county : counties) {Children1 children1 = new Children1();children1.setLabel(String.valueOf(county.getId()));children1.setValue(county.getDistrict());children1s.add(children1);}children.setChildren1s(children1s);}data.setChildren(childrenList);dataList.add(data);}} catch (Exception e) {Logger.logMsg(4, e.getMessage());return Result.build(500, ErrorCode.UNKNOWN_ERROR.getStatusMsg());}return Result.ok(dataList);}

这里需要注意的是

Data data = new Data();需要在for循环里面创建，因为对于不同的province都是一个data,然后每一个data最终添加到datalist里面。如果是在for循环外面实例化，就会被覆盖掉，导致datalist里面的数据只有最后一个

同样的下面的children以及children1也一样