ResultSet不迭代指定列的值

Question

我有一個方法，它通過日期對象返回ResultSet查詢的值。這個障礙是，在我的輸出中，它只返回特定列中的最後一個值。我如何去做這件事？

public Date getTime(){ 
     Date date = null; 
     DateFormat format; 

     try { 

       Class.forName("com.mysql.jdbc.Driver"); 
       Connection con = DriverManager.getConnection(url, "root", ""); 

       Statement stmt = con.createStatement(); 

       ResultSet result = stmt.executeQuery("SELECT * FROM error_log WHERE service_source = 'Billbox' "); 

       while (result.next()) { //retrieve data 
        String ds = result.getString("error_date"); 
        format = new SimpleDateFormat("M/d/yyyy H:m:s a"); 

        date = (Date)format.parse(ds); 

       } 
       con.close(); 

      } catch (Exception ex) { 
       Logger.getLogger(LogDB.class.getName()).log( 
          Level.SEVERE, null, ex); 
      } 
     return date; 
    } 

然後在我的主要方法：

public static void main(String args[]){   
     TestA ea = new TestA(); 
     Date ss = ea.getTime(); 
     System.out.println(ss); 
    } 

但這僅返回我的查詢中的最後一個值。我怎麼能打印出其他（老年人）一起呢？

Answer 1

您需要從您的查詢結果填寫日期的列表。試試這個：

public List<Date> getTime(){ 
     List<Date> dates = new ArrayList<Date>(); 
     DateFormat format; 

     try { 

      Class.forName("com.mysql.jdbc.Driver"); 
      Connection con = DriverManager.getConnection(url, "root", ""); 

      Statement stmt = con.createStatement(); 

      ResultSet result = stmt.executeQuery("SELECT * FROM error_log WHERE service_source = 'Billbox' "); 

      while (result.next()) { //retrieve data 
       String ds = result.getString("error_date"); 
       format = new SimpleDateFormat("M/d/yyyy H:m:s a"); 

       dates.add((Date)format.parse(ds)); 

      } 
      con.close(); 

     } catch (Exception ex) { 
      Logger.getLogger(LogDB.class.getName()).log( 
         Level.SEVERE, null, ex); 
     } 
     return dates; 
    } 

Answer 2

剛：中getTime到List<Date>

 List<Date> lDateDb = new ArrayList<Date>(); 
     while (result.next()) { //retrieve data 
       String ds = result.getString("error_date"); 
       format = new SimpleDateFormat("M/d/yyyy H:m:s a"); 

       date = (Date)format.parse(ds); 
       lDateDb.add(date); 
      } 
     return lDateDb; 

變化返回類型，改變主要以：

public static void main(String args[]){   
    TestA ea = new TestA(); 
    List<Date> lAllDate = ea.getTime(); 
    for (Date lDate : lAllDate) 
    System.out.println(lDate); 
} 

Answer 3

由於while循環，你要簽名到最後一個值。 更改方法

public List<Date> getTime(){ 

您可以嘗試

List<Date> dates = new ArrayList<Date>(); 

，然後你的while循環中;

while (result.next()) { //retrieve data 
        String ds = result.getString("error_date"); 
        format = new SimpleDateFormat("M/d/yyyy H:m:s a"); 

        date = (Date)format.parse(ds); 
        dates.put(date); 


       } 

return dates;