1. MySQL支持的二進制數據類型:tinyblob, blob, mediumblob和longblob。

2. JDBC中我們用PrepareStatement的SetBlob和GetBlob獲取和設置二進制數據。

3. 新建一個JDBC_BLOB工程, 使用我們之前的JDBCUtil.java和jdbc.properties屬性文件, 同時在Resources目錄下存放一個圖片

4. 創建BlobDao.java接口

package com.lywgames.dao;public interface BlobDao {public void createTable();public void insert(String filePath);public void findAll();public void deleteTable(); }

5. 創建BlobDaoImpl.java來對二進制數據進行存儲和獲取

package com.lywgames.dao.impl;import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.sql.Blob; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import com.lywgames.dao.BlobDao; import com.lywgames.util.JDBCUtil;public class BlobDaoImpl implements BlobDao {@Overridepublic void createTable() {Connection conn = null;PreparedStatement ps = null;try {conn = JDBCUtil.getConn();ps = conn.prepareStatement("create table photos(id int(11) not null auto_increment, photo blob, primary key(id))");ps.execute();} catch (SQLException e) {e.printStackTrace();} finally {JDBCUtil.release(conn, ps);}}@Overridepublic void insert(String filePath) {Connection conn = null;PreparedStatement ps = null;try {conn = JDBCUtil.getConn();ps = conn.prepareStatement("insert into photos values(null, ?)");ps.setBlob(1, new FileInputStream(filePath));ps.executeUpdate();} catch (SQLException | IOException e) {e.printStackTrace();} finally {JDBCUtil.release(conn, ps);}}@Overridepublic void findAll() {Connection conn = null;PreparedStatement ps = null;ResultSet rs = null;try {conn = JDBCUtil.getConn();ps = conn.prepareStatement("select photo from photos");rs = ps.executeQuery();int length = -1;byte[] buffer = new byte[1024 * 10];while(rs.next()) {Blob blob = rs.getBlob(1);InputStream is = blob.getBinaryStream();FileOutputStream fos = new FileOutputStream("Resources/" + System.currentTimeMillis() + ".jpg");while((length = is.read(buffer, 0, buffer.length)) != -1) {fos.write(buffer, 0, length);}fos.flush();fos.close();is.close();}} catch (SQLException | IOException e) {e.printStackTrace();} finally {JDBCUtil.release(conn, ps, rs);}}@Overridepublic void deleteTable() {Connection conn = null;PreparedStatement ps = null;try {conn = JDBCUtil.getConn();ps = conn.prepareStatement("drop table photos");ps.execute();} catch (SQLException e) {e.printStackTrace();} finally {JDBCUtil.release(conn, ps);}} }

6. 使用BlobDaoImpl類

package com.lywgames.myjdbc;import com.lywgames.dao.BlobDao; import com.lywgames.dao.impl.BlobDaoImpl;public class MyJDBC {public static void main(String[] args) {BlobDao blobDao = new BlobDaoImpl();blobDao.createTable();blobDao.insert("Resources/1.jpg");blobDao.findAll();blobDao.deleteTable();} }

7. 運行項目在Resources目錄下多了一個圖片。注: eclipse里查看圖片不正常, 嘗試去文件系統里查看。

總結

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