filedao.java

一个jsp的oa系统,里面有很多亮点学习!

package com.oa.lp.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

import com.oa.lp.model.File;
import com.oa.lp.model.Folder;
import com.oa.lp.model.Inform;
import com.oa.lp.util.DTOPopulator;

public class FileDAO {
	private Connection conn;
	public Connection getConn() {
		return conn;
	}

	public void setConn(Connection conn) {
		this.conn = conn;
	}
	/**
	 * 添加文件
	 * @param file
	 * @throws SQLException 
	 */
	public void addFile(File file) throws SQLException{
		String sql = "insert into [FILE](FOLDER_ID,FILE_NAME,FILE_PATH,UPLOAD_TIME,FILE_SIZE,FILE_STATE)" +
					 " values(?,?,?,getDate(),?,?)";
		PreparedStatement pstmt = conn.prepareStatement(sql);
		pstmt.setInt(1,file.getFolderId()); 
		pstmt.setString(2,file.getFileName());
		pstmt.setString(3,file.getFilePath());
		pstmt.setInt(4,file.getFileSize());
		pstmt.setInt(5,file.getFileState());
		pstmt.executeUpdate();
		pstmt.close();
	}
	/**
	 * 删除文件通过ID
	 * @param fileId
	 * @throws SQLException 
	 */
	public void delFile(int fileId) throws SQLException{
		String sql = "delete from [FILE] where FILE_ID=?";
		PreparedStatement pstmt = conn.prepareStatement(sql);
		pstmt.setInt(1,fileId);
		pstmt.executeUpdate();
		pstmt.close();
	}
	/**
	 * 通过文件夹ID 返回文件夹下所有文件集合
	 * @param folderId
	 * @return
	 * @throws Exception 
	 */
	public List listAllFile(int folderId) throws Exception{
		List list = null;
		String sql = "";
		if(folderId==0){
			return list;
		}else{
			sql = "select * from [FILE] where FOLDER_ID="+folderId;
		}
		
		PreparedStatement pstmt = conn.prepareStatement(sql);
		ResultSet rs = pstmt.executeQuery();
		//将结果集中的每一行记录封装成一个对象,再放进集合返回
		list = DTOPopulator.populate(rs, File.class);
		rs.close();
		pstmt.close();
		return list;
	}
	
	/**
	 * 通过文件ID得到文件
	 * @throws Exception 
	 */
	public File getFileById(int fileId) throws Exception{
		File file = new File();
		List list=null;
		String sql = "select * from [FILE] where FILE_ID=?";
		PreparedStatement pstmt = conn.prepareStatement(sql);
		pstmt.setInt(1,fileId);
		ResultSet rs = pstmt.executeQuery();
		list = DTOPopulator.populate(rs, File.class);
		if(list.size()>0){
			file = (File)list.get(0);
		}
		rs.close();
		pstmt.close();
		return file;
	}
}