Java实现分页查询

package util; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; public class BaseDao { private static String driver = "oracle.jdbc.driver.OracleDriver"; private static String url = "jdbc:oracle:thin:@localhost:1521:orcl"; private static String username = "jbit"; private static String password = "jbit"; private static Connection conn; static{ try { Class.forName(driver); } catch(Exception e){ e.printStackTrace(); } } private static Connection getConn(){ if(conn==null){ try { conn=DriverManager.getConnection(url,username,password); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return conn; } public static int execute(String sql){ try { conn=getConn(); PreparedStatement stmt=conn.prepareStatement(sql); return stmt.executeUpdate(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); return -1; } } public static int execute(String sql,Object[] params){ try { conn=getConn(); PreparedStatement stmt=conn.prepareStatement(sql); for(int i=0;i<params.length;i++){ stmt.setObject(i+1, params[i]); } return stmt.executeUpdate(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); return -1; } } public static ResultSet query(String sql){ ResultSet rs=null; try { conn=getConn(); PreparedStatement stmt=conn.prepareStatement(sql); rs=stmt.executeQuery(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } return rs; } public static ResultSet query(String sql,Object[] params){ ResultSet rs=null; try { conn=getConn(); PreparedStatement stmt=conn.prepareStatement(sql); for(int i=0;i<params.length;i++){ stmt.setObject(i+1, params[i]); } rs=stmt.executeQuery(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } return rs; } }