儲存前資料庫資訊

程式碼：

import java.sql.Blob;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.io.*;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
 * blob測試
* create by frank
 * on 2018/02/08
 */
public class BlobTest {
    private static final String JDBC_URL 
 
= "jdbc:mysql://localhost:3306/wechatapp?useSSL=false";
    private static final String USER = "root";
    private static final String PWD = "******";
    private static Connection connection = null;
    static {

        connection = getConn();
}

    public static Connection getConn() {
        Connection connection = null;
 
        try {
            connection = (Connection) DriverManager.getConnection(JDBC_URL, USER, PWD);
} catch (SQLException e) {
            e.printStackTrace();
}
        System.out.println("connected");
        return connection;
}

    public static int update() {

        int rst = 0;
        try 
 
{
            InputStream inputStream = new FileInputStream("E:\\demo.jpg");
String sql = "update ps_blob set img = ? where id = ?";
PreparedStatement preparedStatement =  connection.prepareStatement(sql);
preparedStatement.setBlob(1, inputStream);
preparedStatement.setInt(2, 2);
rst = preparedStatement.executeUpdate();
} catch (Exception e) {
            e.printStackTrace();
}
        return rst;
}

    public static void get() {

        String sql = "select id,img from ps_blob where id = ?";
InputStream inputStream = null;
        try {
            PreparedStatement preparedStatement =  connection.prepareStatement(sql);
preparedStatement.setInt(1, 2);
ResultSet rst = preparedStatement.executeQuery();
            while (rst.next()) {
                System.out.println("id:" + rst.getInt(1));
Blob blob = rst.getBlob(2);
inputStream = blob.getBinaryStream();
OutputStream outputStream =new FileOutputStream("E:\\demo1.jpg");
                int x = 0;
                byte[] a = new byte[1024];
                while ((x = inputStream.read(a)) != -1)
                    outputStream.write(a);
outputStream.close();
inputStream.close();
}
        } catch (Exception e) {
            e.printStackTrace();
}
    }

    public static void main(String[] args) {

        System.out.println( BlobTest.update());
BlobTest.get();
}

}

執行完成後檢視 E:\\demo.jpg1

資料庫資料變化

只顯示(BLOB)代表插入二進位制流位 byte位元組數為0