为什么我用prepareStatement执行批量插入总是只能插入一条数据

PreparedStatement pstmt3= conn.prepareStatement("insert into toupiao(id,xxid,xuanxiang) values(?,?,?)");
     for(int i=0,n=xx.length;i <n;i++)
                       {
                       pstmt3.setInt(1,newid);// 这里相同了会变成更新.
                       pstmt3.setInt(2,i+1);
                       pstmt3.setString(3,xx[i]);
                       pstmt3.addBatch();
     }
     inserts=pstmt3.executeBatch();