db.java

自己编写的一个spring框架下实现文件上传的例子

package com.mr.UpLoad;

import java.math.BigDecimal;
import java.sql.*;

/**
 * SQL Server2000 DB Manager
 * @author suHao
 *
 */
public class DB {
	

	private static  Connection conn = null;
	private static String url = 
		"jdbc:microsoft:sqlserver://172.16.162.148:1433;DatabaseName=DB_upload14;user=sa;password=as";

	static{
		try {
			
			Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");		
			conn = DriverManager.getConnection(url);
	
		} catch (Exception e) {
			System.err.println(e.getMessage());
		}
	}

	/**
	 *  executeQuery
	 *  @param RO_SQL read Only sql
	 *  @param params array of parameters
	 *  @return ResultSet
	 */
	public static ResultSet executeQuery(String RO_SQL, Object[] params) {
		
		if (RO_SQL == null || RO_SQL.length() == 0)
			throw new IllegalArgumentException("Required parameter missing - " + RO_SQL);
		//
		ResultSet rs = null;
		PreparedStatement pstmt = null;
		
		try
		{
			pstmt = conn.prepareStatement (RO_SQL, ResultSet.TYPE_SCROLL_INSENSITIVE, 
					ResultSet.CONCUR_READ_ONLY);
			
			//	Set Parameter
			if (params != null)
			{
				for (int i = 0; i < params.length; i++)
				{
					Object param = params[i];
					if (param == null)
						pstmt.setNull(i+1, Types.VARCHAR);
					else if (param instanceof String)
						pstmt.setString(i+1, (String)param);
					else if (param instanceof Integer)
						pstmt.setInt(i+1, ((Integer)param).intValue());
					else if (param instanceof BigDecimal)
						pstmt.setBigDecimal(i+1, (BigDecimal)param);
					else if (param instanceof Timestamp)
						pstmt.setTimestamp(i+1, (Timestamp)param);
				}
			}
			//
			rs = pstmt.executeQuery();
		
		}
		catch (SQLException e)
		{
			System.out.println(RO_SQL +  e.getMessage());
		//	throw new DBException(e);
		}
		
		return rs;
	} //executeQuery


	/**
	 * Execute Update.
	 * @param sql
	 * @return number of rows updated or -1 if error
	 */
	public static int executeUpdate(String sql) {
		
		return executeUpdate (sql, null);
	}
	
	/**
	 *	Execute Update.
	 *  @param sql sql
	 *  @param params array of parameters
	 *  @return number of rows updated or -1 if error
	 */
	public static int executeUpdate (String sql, Object[] params)
	{
		if (sql == null || sql.length() == 0)
			throw new IllegalArgumentException("Required parameter missing - " + sql);
		//
		int no = -1;
		PreparedStatement pstmt = null;
		
		try
		{
			pstmt = conn.prepareStatement (sql, ResultSet.TYPE_FORWARD_ONLY, 
					ResultSet.CONCUR_UPDATABLE);
			
			//	Set Parameter
			if (params != null)
			{
				for (int i = 0; i < params.length; i++)
				{
					Object param = params[i];
					if (param == null)
						pstmt.setNull(i+1, Types.VARCHAR);
					else if (param instanceof String)
						pstmt.setString(i+1, (String)param);
					else if (param instanceof Integer)
						pstmt.setInt(i+1, ((Integer)param).intValue());
					else if (param instanceof BigDecimal)
						pstmt.setBigDecimal(i+1, (BigDecimal)param);
					else if (param instanceof Timestamp)
						pstmt.setTimestamp(i+1, (Timestamp)param);
				}
			}
			//
			no = pstmt.executeUpdate();
			
		}
		catch (SQLException e)
		{
			System.out.println(sql +  e.getMessage());
		//	throw new DBException(e);
		}
		finally
		{
			//  Always close cursor
			try
			{
				pstmt.close();
			}
			catch (SQLException e2)
			{
				System.out.println("Cannot close prepareStatement");
			}
		}
		return no;
	}	//	executeUpdate


	/**
	 * DB is connected 
	 * @return
	 */
	public static boolean isConnected(){
		return conn != null;
	}
	
	/**
	 * Connection instance
	 * @return
	 */
	public static Connection getConnection()
	{
		return conn;
	}
	
	/**
	 *	Prepare Read Only Statement
	 *  @param RO_SQL sql (RO)
	 * 	@param trxName transaction
	 *  @return Prepared Statement
	 */
	public static PreparedStatement prepareStatement (String RO_SQL)
	{
		try{
			return conn.prepareStatement(RO_SQL, ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY);
		}catch(Exception e){
			return null;
		}
	}	//	prepareStatement
	
	
	/**
	 * 	Get Value from sql
	 * 	@param sql sql
	 * 	@param str_param1 parameter 1
	 * 	@return first value or -1
	 */
	public static int getSQLValue (String sql, String str_param1)
	{
		int retValue = -1;
		PreparedStatement pstmt = null;
		try
		{
			pstmt = prepareStatement(sql);
			pstmt.setString(1, str_param1);
			ResultSet rs = pstmt.executeQuery();
			if (rs.next())
				retValue = rs.getInt(1);
			else
				System.out.println("No Value " + sql + " - Param1=" + str_param1);
			rs.close();
			pstmt.close();
			pstmt = null;
		}
		catch (Exception e)
		{
			System.out.println( sql + " - Param1=" + str_param1 + e);
		}
		finally
		{
			try
			{
				if (pstmt != null)
					pstmt.close ();
			}
			catch (Exception e)
			{}
			pstmt = null;
		}
		return retValue;
	}	//	getSQLValue
	
}