自己建了一個實體類
public class MissPoint implements Serializable{ private static final long serialVersionUID = -3623219494524321164L; /*** 時間*/
private String date; /*** 酒店數 */
private Integer count; /*** 酒店id*/
private List<Integer> hotelList; /**需要查詢的時間**/
private Date occurDate; /**所有漏點的數據**/
private List<DataMap> maps ; private Map<Date, List<Integer>> data = new HashMap<Date, List<Integer>>(); public MissPoint() { // TODO Auto-generated constructor stub
} public MissPoint(Date date,List<DataMap> maps) { // TODO Auto-generated constructor stub
this.occurDate = date; this.maps = maps; } private void setData(){ for(DataMap map : maps){ int hotelid = map.getInt("hotel_id"); List<Integer> indexList = DataPointHelper.findByIsZero(map.get("text"), 0, -1); for(Integer index : indexList){ Date pointDate = DataPointHelper.getTimeByIndex(occurDate, index); if(data.containsKey(pointDate)){ data.get(pointDate).add(hotelid); }else{ List<Integer> list = new ArrayList<Integer>(); list.add(hotelid); data.put(pointDate, list); } } } } public List<MissPoint> getList(){ List<MissPoint> missPoints = new ArrayList<MissPoint>(); this.setData(); for(Map.Entry<Date, List<Integer>> entry : data.entrySet()){ MissPoint point = new MissPoint(); point.setDate(DateHelper.format(entry.getKey(), "yyyy-MM-dd HH:mm:ss")); point.setCount(entry.getValue().size()); point.setHotelList(entry.getValue()); missPoints.add(point); } return missPoints; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((date == null) ? 0 : date.hashCode()); return result; } public String getDate() { return date; } public void setDate(String date) { this.date = date; } public Integer getCount() { return count; } public void setCount(Integer count) { this.count = count; } public List<Integer> getHotelList() { return hotelList; } public void setHotelList(List<Integer> hotelList) { this.hotelList = hotelList; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; MissPoint other = (MissPoint) obj; if (date == null) { if (other.date != null) return false; } else if (!date.equals(other.date)) return false; return true; } @Override public String toString() { return "[date=" + date + ", count=" + count + ", hotelList=" + hotelList + "]"; } }
其中給外界提供的方法寫成了getList()，轉json的時候一直報錯，此類的list屬性為空，納悶了，找了半天沒有找到名為list的屬性，后來突發奇想，是不是那個getList(),讓他以為我是獲取屬性list的值，但是又沒有那個屬性，所以空指針了，只能這么理解了，不知道對不對，反正改了方法名就不在報錯了