Question

我正在使用此代码一次获取1000条记录。它工作正常，但我如何停止在第一个1000运行我的工作，然后拿起我离开的地方，并获得下一组1001 - 2000，运行下一个工作，等等？请帮助我有点卡住。

public class PaginationJDBC {

   public static void main(String arg) {
       for(int i=1; i<=5 ;i++){
              paginationMethod(i);
   }
}

static void paginationMethod(int n){
       Connection con = null;
       PreparedStatement ps = null;
       ResultSet rs = null;                  
       try {
              con = gettingMyConnection;
              ps = con.prepareStatement("select emp.id, emp.name  "
                + "from ( select rownum rn, e.* from EMPLOYEE e) emp "
                + "where rn >=? and rn< =? ");
              ps .setInt(1, (n*1000) -999);
              ps .setInt(2, n*1000);

              rs = prepStmt.executeQuery();
              int rowCount = 0;
              while (rs.next()) {
              ++rowCount;
                    System.out.print(rs.getInt(1)+" ");
                    System.out.println(rs.getString(2));
              if(rowCount >= 1000-4) {
               system.out.printlin("total records" + rowCount);
              //I would like to run a job here, returns the 1st 1000
               return;
              } 
              if(rowCount >= 1001) {
               **// this is where I would do the next job between 1001 and 2000 and so on, but I'm stuck**
              }

       } catch (ClassNotFoundException e) {
              e.printStackTrace();
       } catch (SQLException e) {
              e.printStackTrace();
       }
       finally{
              try {
                    if(rs!=null) rs.close(); //close resultSet
                    if(ps !=null) ps .close(); //close PreparedStatement
                    if(con!=null) con.close(); // close connection
              } catch (SQLException e) {
                    e.printStackTrace();
              }
       }

}

}

Answer 1

使用您的应用程序记录您所处的位置，例如，假设我今天显示记录，一次显示20行。我可以写：

第1页

select * 
from T 
where date_col = trunc(sysdate) 
order by id desc
fetch first 20 rows only

我将ID = 100提取到80 ...我注意到80.我的下一个查询将是

select * 
from T 
where date_col = trunc(sysdate) 
AND ID<80  <<==== additional predicate
order by id desc
fetch first 20 rows only

我的下一个查询是

select * 
from T 
where date_col = trunc(sysdate) 
AND ID<60
order by id desc
fetch first 20 rows only

等等。

JDBC分页Oracle一次执行1000然后获取下一个1000

1 个答案: