Question

public static List<SPACE_CreateLicenseModel> SPACE_getDetails() throws ClassNotFoundException, FileNotFoundException, JSONException{

    SPACE_CreateLicenseModel view = new SPACE_CreateLicenseModel();
    Statement stmt = null;
    Connection connect = null;
    List<SPACE_CreateLicenseModel> allData = new ArrayList<SPACE_CreateLicenseModel>();
    try {
        connect = SPACE_DBController.SPACE_getConnection();
        stmt = connect.createStatement();
        JSONObject obj = SPACE_Parse.parse ("C:/Users/Rachana/workspace/SPACEOM/WebContent/Data/SPACE_Database.json");
        String tablename = obj.getString("table_name");
        String sql = "SELECT * FROM " + tablename + " WHERE (SPLD_LicenseActiveStatus <> 5 OR SPLD_LicenseActiveStatus IS NULL)";
        ResultSet result = stmt.executeQuery(sql);
        int i =0;
            while (result.next()) {     
                view.setSPLD_DeviceID_Mfg(result.getString(1));
                view.setSPLD_DeviceID_ModelNo(result.getString(2));
                view.setSPLD_DeviceID_SrNo(result.getString(3));
                view.setSPLD_DeviceID_Search_mode(result.getByte(4));
                view.setSPLD_LicenseType(result.getByte(5));
                view.setSPLD_LicenseTypeChangedDate(result.getDate(6));
                view.setSPLD_LicenseActiveStatus(result.getByte(7));
                view.setSPLD_LicenseActiveDate(result.getDate(8));
                view.setSPLD_LicenseAccess(result.getByte(9));
                view.setSPLD_LicenseAccessMaxNo(result.getInt(10));
                view.setSPLD_LicenseAccessCounter(result.getInt(11));
                view.setSPLD_LicenseStartDate(result.getDate(12));
                view.setSPLD_LicenseExpiryDate(result.getDate(13));
                view.setSPLD_LicenseeOrg(result.getString(14));
                view.setSPLD_LicenseeAddress(result.getString(15));
                view.setSPLD_LocationActive(result.getString(16));
                view.setSPDL_Longitude(result.getDouble(17));
                view.setSPDL_Latitude(result.getDouble(18));
                view.setSPDL_LocationTolerance(result.getFloat(19));
                view.setSPLD_FutureOption1(result.getString(20));
                view.setSPLD_FutureOption2(result.getString(21));
                view.setSPLD_FutureOption3(result.getString(22));
                view.setSPLD_FutureOption4(result.getInt(23));
                view.setSPLD_FutureOption5(result.getInt(24));
                view.setSPLD_StatCounter1_FirstUseDate(result.getDate(25));
                view.setSPLD_StatCounter2_MessageTotal(result.getInt(26));
                view.setSPLD_StatCounter3_FailedAttempts(result.getInt(27));
                view.setSPLD_StatCounter4_FirstFailedAttemptDate(result.getDate(28));
                view.setSPLD_StatCounter5_LastFailedAttemptDate(result.getDate(29));
                view.setSPLD_StatCounter6(result.getInt(30));
                view.setSPLD_StatCounter7(result.getInt(31));
                view.setSPLD_StatCounterOption1(result.getString(32));
                view.setSPLD_StatCounterOption2(result.getString(33));
                view.setSPLD_StatCounterOption3(result.getString(34));
                view.setSPLD_StatCounterOption4(result.getInt(35));
                view.setSPLD_StatCounterOption5(result.getInt(36));
                view.setSPLD_MainContact1Name(result.getString(37));
                view.setSPLD_MainContact2Name(result.getString(38));
                view.setSPLD_MobileNo1(result.getString(39));
                view.setSPLD_MobileNo2(result.getString(40));
                view.setSPLD_EmailID1(result.getString(41));
                view.setSPLD_EmailID2(result.getString(42));
                view.setSPLD_CustomerDetailOption1(result.getString(43));
                view.setSPLD_CustomerDetailOption2(result.getString(44));
                view.setSPLD_BroadCastGEN1(result.getString(45));
                view.setSPLD_BroadCastGEN2(result.getString(46));
                view.setSPLD_BroadCastID1(result.getInt(47));
                view.setSPLD_DevSpecGEN1(result.getString(48));
                view.setSPLD_DevSpecGEN2(result.getString(49));
                view.setSPLD_DevSpecGEN3(result.getString(50));
                view.setSPLD_DevSpecID1(result.getInt(51));
                view.setSPLD_DevSpecID2(result.getInt(52));
                view.setSPLD_MessageStatus(result.getString(53).charAt(0));
                allData.add(i,view);
                i++;
            }
    } catch (SQLException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    } catch (ClassNotFoundException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }finally{
          //finally block used to close resources
          try{
             if(stmt!=null)
                stmt.close();
          }catch(SQLException se2){
          }// nothing we can do
          try{
             if(connect!=null)
                connect.close();
          }catch(SQLException se){
             se.printStackTrace();
          }

    }
    return allData;

}

我正在获取数据库的所有行并将其存储在数组中。但是只显示最后一行正在打印。列表元素被覆盖。即allData.add（1，view），allData.add（2，view），allData.add（3，view），allData.add（4，view）等等一切都是一样的。

Answer 1

由于您没有为循环的每次迭代创建新的Object，它会重新使用相同的对象，因此请尝试

Statement stmt = null;
Connection connect = null;
List<SPACE_CreateLicenseModel> allData = new ArrayList<SPACE_CreateLicenseModel>();
try {
    connect = SPACE_DBController.SPACE_getConnection();
    ....
        while (result.next()) {    
           SPACE_CreateLicenseModel view = new SPACE_CreateLicenseModel();

Answer 2

<强>原因：

目前，每一行都会更新相同的对象，因此列表中的所有对象都具有相同的值（最后一行）。

解决：

每次循环时，您需要为每一行初始化SPACE_CreateLicenseModel。

while (result.next()) { SPACE_CreateLicenseModel view = new SPACE_CreateLicenseModel(); view.setSPLD_DeviceID_Mfg(result.getString(1)); . . allData.add(i,view); i++; }

希望这有帮助

Answer 3

使用while循环的每次迭代创建一个新的视图对象。每次循环遍历相同的视图对象时，都会在内存中重写。循环运行的最后时间将其替换为打印数据时显示的最后一行值...

while(yourCondition){
    view = new SPACE_CreateLicenseModel();
    //your code goes here....
}

在循环中添加上面的行将创建一个新的视图对象，并将添加到你的allData变量中。

数据库行读入对象列表

3 个答案: