【MySql】数据库写入图片和读出图片

//写入图片到数据库
	static void insert() throws Exception
	{
		String sql ="insert into pics (pic) values (?)";
		Connection conn=JdbcUtilSingle.getConnection();
		
		PreparedStatement pst=conn.prepareStatement(sql);
		
		File file = new File("p_large_CuRa_47110000afc8121a.jpg");
		
		InputStream inputstream = new BufferedInputStream(new FileInputStream(file));
		
		pst.setBinaryStream(1, inputstream, (int)file.length());//说明：这里一定要转化为int，否则会报错，length()返回值为long类型的
		//setBinaryStream(1, inputstream,(long)file.length());
		
		int i = pst.executeUpdate();
		
		System.out.println(i);
		
		JdbcUtilSingle.free(null, pst, conn);
	}
	//读出图片信息
	static void write() throws Exception
	{
		String sql="select * from pics ";
		Connection conn=JdbcUtilSingle.getConnection();
		PreparedStatement pst=conn.prepareStatement(sql);
		ResultSet rs=pst.executeQuery();
		
		File file = new File("mypic.jpg");
		
		while(rs.next())
		{
			//Blob blob = rs.getBlob(1);
			//InputStream in = blob.getBinaryStream();
			//上面兩行的作用和下面這行相同
			InputStream in = rs.getBinaryStream(1);
			
			OutputStream out = new BufferedOutputStream(new FileOutputStream(file));
			
			byte buff[]= new byte[1024];
			//寫入文件
			for(int i=0;(i=in.read(buff))>0;)
			{
				out.write(buff, 0, i);
			}
		}
		
		JdbcUtilSingle.free(rs, pst, conn);