Introduction of generic method

  Generic method of introduction: 

public <E> void insertOrUpdateHistoryData (Integer year, month The Integer, Integer parkId, type Integer, Integer Number, E E) {
         // the computed data into the database, whether the next look at the database exists, so do not repeat calculated
         // here is calculated every time, whether to go to query the database table data of the month, if there are updates, not to add. 
        = Data String JSONObject.toJSONString (E); 
        historyData historyData = historyDataService.isExist (year, month The, parkId,. 1,. 1 );
         IF (! HistoryData = null ) {
             // if there is updated data 
            historyData.setData (data); 
            historyDataService.updateByPrimarykey (historyData); 
        } the else{
             // does not exist, add data 
            historyDataService.insert (year, month The, parkId,. 1,. 1 , Data); 
        } 
    }

Such a method is used; generic description: https://www.cnblogs.com/coprince/p/8603492.html