如何停止Java結果：1錯誤？爲什麼會發生？

我正在使用NetBeans 8.0上的java swing。當我運行此代碼時，我有重複的消息。最後我評論它。之後，系統不停止工作。最後我使用任務管理器並停止整個系統。然後我有Java結果：1錯誤。

這是我的源代碼。
如何停止Java結果：1錯誤？爲什麼會發生？

public void SaveDamage(JTextField txtItID, JTextField txtInID, JTextField txtQty, JTextField txtTotal) { 
    try { 
     ResultSet rs1 = JDBC.getData("select inid from damage where inid='" + txtInID.getText() + "'"); 
     if (rs1.next()) { 
      JOptionPane.showMessageDialog(null, "This invoice is already finalized", "Error", JOptionPane.ERROR_MESSAGE); 
     } else { 
      try { 
       boolean bool = JDBC.putData("insert into damage(itid, qty,total, inid) values('" + txtItID.getText() + "' , '" + txtQty.getText() + "' ,'"+txtTotal.getText()+"' , '" + txtInID.getText() + "')"); 
       if (bool) { 
        JOptionPane.showMessageDialog(null, "damaged saved"); 
        try { 
         ResultSet rs = JDBC.getData("select avqty from item where itid='" + txtItID.getText() + "' "); 
         while (rs.first()) { 
          int newqty = rs.getInt("avqty") - Integer.valueOf(txtQty.getText()); 
          try { 
           boolean bool1 = JDBC.putData("update item set avqty = '" + newqty + "' where itid = '" + txtItID.getText() + "' "); 
           if (bool1) { 
            // JOptionPane.showMessageDialog(null, txtItID.getText()); 
            // JOptionPane.showMessageDialog(null, "item updated"); 
           } 
          } catch (Exception e) { 
           e.printStackTrace(); 
          } 
         } 
        } catch (Exception e) { 
         e.printStackTrace(); 
        } 
       } 
      } catch (Exception e) { 
       e.printStackTrace(); 
      } 
     } 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } 
}

這是我的JDBC類。

package Model; 
//import static Model.JDBC.con; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.PreparedStatement; 
import java.sql.ResultSet; 
import java.sql.Statement; 
import javax.swing.JOptionPane; 

public class JDBC { 
    static String driver = "com.mysql.jdbc.Driver"; 
    static String url = "jdbc:mysql://localhost/cat"; 
    static Connection con; 
    static boolean b ; 

    public static void setCon() { 
     try { 
      Class.forName(driver); 
      con = DriverManager.getConnection(url, "root", "access456"); 
     } catch (Exception ex) { 
      JOptionPane.showMessageDialog(null, ex); 
     } 
    } 

    public static Connection getCon() throws Exception { 
     if (con == null) { 
      setCon(); 
     } 
     return con; 
    } 

    public static boolean putData(String sql) { 
     try { 
      PreparedStatement state = getCon().prepareStatement(sql); 
      state.executeUpdate(); 
      b = true; 
     } catch (Exception ex) { 
      b= false; 
      JOptionPane.showMessageDialog(null, ex); 
     } 
     return b; 
    } 

    public static ResultSet getData(String sql) throws Exception { 
     Statement state = JDBC.getCon().createStatement(); 
     ResultSet rset = state.executeQuery(sql); 
     return rset; 
    } 
}

來源

2014-07-21 Stack_User_123

我相信你可以簡化這些'try'-'catch'語句到一個塊中，因爲catch是相同的。 –