用JDBC访问二进制类型的数据

用JDBC访问二进制类型的数据

 

public class BlobTest {
	public static void main(String[] args) throws SQLException, IOException, ClassNotFoundException {
		// create();
		read();
	}

	// 从数据库读取二进制类型的数据
	static void read() throws SQLException, IOException, ClassNotFoundException {
		Connection conn = null;
		PreparedStatement ps = null;
		ResultSet rs = null;

		try {
			// 1.加载驱动
			Class.forName("com.mysql.jdbc.Driver");

			// 2.建立连接
			conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbc", "root", "123456");

			// 3.创建语句
			ps = conn.prepareStatement("select big_bit from blob_test");

			// 4.执行语句
			rs = ps.executeQuery();

			// 5.处理结果
			while (rs.next()) {
				Blob blob = rs.getBlob(1);
				InputStream in = blob.getBinaryStream();

				File file = new File("IMG_0002_bak.jpg");
				OutputStream out =  new BufferedOutputStream(new FileOutputStream(file));
				byte[] buff = new byte[1024];
				for (int i = 0; (i = in.read(buff)) > 0;) {
					out.write(buff, 0, i);
				}

				out.close();
				in.close();
			}
		} finally {
			if (rs != null)	rs.close(); rs = null;
			if (ps != null)	ps.close();	ps = null;
			if (conn != null) conn.close();	conn = null;
		}
	}

	// 把二进制类型的数据(这里是一张图片)存入数据库
	static void create() throws SQLException, IOException, ClassNotFoundException {
		Connection conn = null;
		PreparedStatement ps = null;
		ResultSet rs = null;

		try {
			// 1.加载驱动
			Class.forName("com.mysql.jdbc.Driver");

			// 2.建立连接
			conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbc", "root", "123456");

			// 3.创建语句
			String sql = "insert into blob_test(big_bit) values (?)";
			ps = conn.prepareStatement(sql);

			File file = new File("IMG_0002.jpg");
			InputStream in = new BufferedInputStream(new FileInputStream(file));
			
			ps.setBinaryStream(1, in, (int) file.length());

			// 4.执行语句
			int i = ps.executeUpdate();
			in.close();

			System.out.println("i=" + i);
		} finally {
			if (rs != null)	rs.close(); rs = null;
			if (ps != null)	ps.close();	ps = null;
			if (conn != null) conn.close();	conn = null;
		}
	}
}