Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: empty String

Question

       if(s.equals("出售")){
              try{
 Class.forName("org.gjt.mm.mysql.Driver");
         Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/myjava", "root", "sa");
         Statement stmt=con.createStatement();
         stmt.executeUpdate("insert into sale values('"+store+"','"+pro+"',"+price+","+quantity+","+total+");");
         lb6.setText("成功出售");
         con.close();
}
catch(Exception e){

System.out.println("connect fail");
}
       
              
             }
else if(s.equals("当天销售记录")){
try{
     Class.forName("org.gjt.mm.mysql.Driver");
         Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/myjava", "root", "sa");
         Statement stmt=con.createStatement();
         ResultSet rs=stmt.executeQuery("select * from sale;");
         while(rs.next()){
         
          System.out.print("连锁店:"+rs.getString(1)+"  ");
           
          System.out.print("商品:"+rs.getString(2)+"  ");
        
          System.out.print("单价:"+rs.getInt(3)+"  ");
         
          System.out.print("数量:"+rs.getInt(4)+"  ");
          System.out.println("总价:"+rs.getInt(5)+"  ");
         }
         con.close();
         
         }
         catch(Exception e){
          System.out.print("查询失败");
         }
         }//不好意思，还是那段代码的问题，为什么当我运行时直接进行查询语句是，系统会抛出异常，而当我插入一个数据后，它却能正常的查询大家原谅，自学的，基础不是很稳

Answer 1

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: empty St
ring
        at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
        at java.lang.Double.parseDouble(Unknown Source)
        at TestSystem.actionPerformed(TestSystem.java:108)
        at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
        at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
        at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
        at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Sour

Answer 2

 System.out.print("单价:"+rs.getInt(3)+" ");
  
  System.out.print("数量:"+rs.getInt(4)+" ");
  System.out.println("总价:"+rs.getInt(5)+" ");这几个值中有一某些是空的，空字符串转整型的时候就会有 NumberFormatException 

Answer 3

System.out.print("单价:"+rs.getInt(3)+" ");
   
  System.out.print("数量:"+rs.getInt(4)+" ");
  System.out.println("总价:"+rs.getInt(5)+" ");这几个值中有一某些是空的，空字符串转整型的时候就会有 NumberFormatException
debug   一下 看看