Mysql存储二进制对象数据问题

这篇文章主要介绍了Mysql存储二进制对象数据问题，具有很好的参考价值，希望对大家有所帮助。如有错误或未考虑完全的地方，望不吝赐教

Mysql存储二进制对象数据

首先数据库存储一个Object对象

需要在数据库表中定义一个blob类型的字段

与数据库对应的实体类

编写一个操作二进制的工具类

import java.io.*; /** * byte[]类型操作类 */ public class BlobUtil { /** * 把object对象序列化为二进制字节数组 * @param object * @return */ public static byte[] setObject(Object object) { ByteArrayOutputStream baos = null; ObjectOutputStream out = null; try { baos = new ByteArrayOutputStream(); out = new ObjectOutputStream(baos); out.writeObject(object); } catch (Exception e) { e.printStackTrace(); } finally { if (out != null) { try { out.close(); } catch (IOException e) { e.printStackTrace(); } } if (baos != null) { try { baos.close(); } catch (IOException e) { e.printStackTrace(); } } } return baos.toByteArray(); } /** * 把二进制字节数组反序列化为object对象 * object当中的每个javaBean对象都必须实现序列化 * 最外层的类必须生成一个序列化ID * @param bytes * @return */ public static Object getObject(byte[] bytes) { Object obj = null; ByteArrayInputStream bais = null; ObjectInputStream in = null; try { bais = new ByteArrayInputStream(bytes); in = new ObjectInputStream(bais); obj = in.readObject(); } catch (Exception e) { e.printStackTrace(); } finally { if (in != null) { try { in.close(); } catch (IOException e) { e.printStackTrace(); } } if (bais != null) { try { bais.close(); } catch (IOException e) { e.printStackTrace(); } } } return obj; } }

需要转换为byte[]的对象必须实现序列化和生成一个序列化ID，生成一个序列化ID是为了解决类当中一但有修改，反序列化时序列化ID就会对应不上，如下图：

类中如果有其他类为变量也需要实现序列化，否则从数据库中取出数据然后反序列化成Object对象的时候会直接报错

对user的数据进行操作

import java.io.Serializable; /** * @author * @description * @date */ public class UserVO implements Serializable { private static final long serialVersionUID = 1L; private String userId; private String userName; private String password; public String getUserId() { return userId; } public void setUserId(String userId) { this.userId = userId; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }

调用二进制工具类来转换数据然后进行存取就可以了。

测试功能

public class TestMain { public static void main(String[] args) { UserVO user = new UserVO(); user.setUserId("123456"); user.setUserName("张三"); byte[] dataValue = BlobUtil.setObject(user); System.out.println("=====对象转换成blob类型数据====="+Arrays.toString(dataValue)); UserVO userVO = (UserVO) BlobUtil.getObject(dataValue); System.out.println("=====blob类型数据转换成对象====="+ JSONObject.toJSONString(userVO)); } }

打印输出

=====对象转换成blob类型数据=====[-84, -19, 0, 5, 115, 114, 0, 53, 99, 111, 109, 46, 100, 111, 108, 112, 104, 105, 110, 46, 109, 111, 100, 117, 108, 101, 115, 46, 116, 109, 115, 46, 100, 111, 109, 97, 105, 110, 46, 99, 117, 115, 116, 111, 109, 101, 114, 115, 101, 114, 118, 105, 99, 101, 46, 85, 115, 101, 114, 86, 79, 0, 0, 0, 0, 0, 0, 0, 1, 2, 0, 3, 76, 0, 8, 112, 97, 115, 115, 119, 111, 114, 100, 116, 0, 18, 76, 106, 97, 118, 97, 47, 108, 97, 110, 103, 47, 83, 116, 114, 105, 110, 103, 59, 76, 0, 6, 117, 115, 101, 114, 73, 100, 113, 0, 126, 0, 1, 76, 0, 8, 117, 115, 101, 114, 78, 97, 109, 101, 113, 0, 126, 0, 1, 120, 112, 112, 116, 0, 6, 49, 50, 51, 52, 53, 54, 116, 0, 6, -27, -68, -96, -28, -72, -119]
=====blob类型数据转换成对象====={"userId":"123456","userName":"张三"}