Big Data-Save MP3 to database and read out "Dark Horse programmer _ ultra-comprehensive javaweb video tutorial Vedio" Day17

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Dark Horse Programmer _ Super Comprehensive Javaweb video tutorial vedio\ Dark Horse Programmer _ Ultra Comprehensive Javaweb Tutorial-source note \javaweb Video tutorial _day17-data source \day17_code\day17_1\

Big Data

Goal: Save the MP3 to the database!

Add the following configuration in My.ini!

max_allowed_packet=10485760

1 What is Big Data

The so-called Big data, is the large byte data, or large character data. The following types are available in standard SQL to hold large data types:

Type

Length

Tinyblob

28--1b(256B)

Blob

216-1b(64K)

Mediumblob

224-1b(16M)

Longblob

232-1b(4G)

Tinyclob

28--1b(256B)

Clob

216-1b(64K)

Mediumclob

224-1b(16M)

Longclob

232-1b(4G)

However, in MySQL , tinyclob,clob,mediumclob, Longclob four types, but uses the following four types to handle text Big data:

Type

Length

Tinytext

28--1b(256B)

Text

216-1b(64K)

Mediumtext

224-1b(16M)

Longtext

232-1b(4G)

first we need to create a table with a Mediumblob ( 16M ) type of field.

 

CREATE TABLE tab_bin (id INT PRIMARY KEY auto_increment,filenamevarchar (), data mediumblob);

inserting binary data into a database needs to be used PreparedStatement as the original setbinarystream (int, inputsteam) method to complete.

con = Jdbcutils. Getconnection ();

string sql = "INSERT into Tab_bin (filename,data) VALUES (?,?)";

pstmt = Con.preparestatement (sql);

pstmt.setstring (1, "a.jpg");

inputstream in = new  fileinputstream ("f:\\a.jpg");

pstmt.setbinarystream (2, in);

pstmt.executeupdate ();

  read binary data, need to use after query resultset getbinarystream () method to get the input stream object. In other words, preparedstatement setxxx () , then resultset getxxx () Span style= "font-family: the song Body;" >

Con = jdbcutils. getconnection ();

String sql = "Select Filename,data from Tab_bin where id=?";

pstmt = con.preparestatement (sql);

Pstmt.setint (1, 1);

rs = Pstmt.executequery ();

Rs.next ();

String filename = rs.getstring ("filename");

OutputStream out = new fileoutputstream ("f:\\" + filename);

InputStream in = Rs.getbinarystream ("Data");

Ioutils. Copy (in, out);

Out.close ();

another way is to wrap the data that you want to store into Blob type, and then call preparedstatement 's setblob () method to set the data

con = jdbcutils. Getconnection ();

String sql = "INSERT into Tab_bin (filename,data) VALUES (?,?)";

Pstmt = con.preparestatement (sql);

Pstmt.setstring (1, "a.jpg");

File File = new  file ("f:\\a.jpg");

byte [] datas = FileUtils. getBytes (file);// Get data from a file

Blob blob = new  serialblob ( datas);// blob object

Pstmt.setblob (2, BLOB);// settings

pstmt.executeupdate ();

Con = jdbcutils. getconnection ();

String sql = "Select Filename,data from Tab_bin where id=?";

pstmt = con.preparestatement (sql);

Pstmt.setint (1, 1);

rs = Pstmt.executequery ();

Rs.next ();

String filename = rs.getstring ("filename");

File File = new file ("f:\\" + filename);

Blob blob = Rs.getblob ("Data");

byte [] datas = blob.getbytes (0, (int) file.length ());

FileUtils. Writebytearraytofile (file, datas);

The class teacher knocks the code:

 PackageCn.itcast.demo4;ImportJava.io.FileInputStream;Importjava.io.FileNotFoundException;ImportJava.io.FileOutputStream;Importjava.io.IOException;ImportJava.io.InputStream;ImportJava.io.OutputStream;ImportJava.sql.Blob;Importjava.sql.Connection;Importjava.sql.PreparedStatement;ImportJava.sql.ResultSet;Importjava.sql.SQLException;ImportJavax.sql.rowset.serial.SerialBlob;Importorg.apache.commons.io.IOUtils;Importorg.junit.Test;Importcn.itcast.demo3.JdbcUtils;/*** Big Data *@authorCXF **/ Public classDemo4 {/*** Save the MP3 to the database. * @throwsSQLException *@throwsIOException *@throwsFileNotFoundException*/@Test Public voidFUN1 ()throwsException {/** 1. Get connection * 2. Give the SQL template, create PSTMT * 3. Set the parameters in the SQL template * 4. Call Pstmt's executeupdate () Line*/Connection con=jdbcutils.getconnection (); String SQL= "INSERT into Tab_bin values (?,?,?)"; PreparedStatement pstmt=con.preparestatement (SQL); Pstmt.setint (1, 1); Pstmt.setstring (2, "Streamer flying. mp3"); /*** need to get BLOB * 1. We have the file, the target is blob * 2. First turn the file into byte[] * 3. Use byte[] to create a blob*/        //convert files to byte[]        byte[] bytes = Ioutils.tobytearray (NewFileInputStream ("f:/Streamer MP3")); //Create a BLOB using byte[]Blob blob =NewSerialblob (bytes); //Setting ParametersPstmt.setblob (3, BLOB);    Pstmt.executeupdate (); }        /*** Read mp3 from database *@throwsSQLException*/@Test Public voidFun2 ()throwsException {/** 1. Create connection*/Connection con=jdbcutils.getconnection (); /** 2. Give the SELECT statement template to create the pstmt*/String SQL= "SELECT * FROM Tab_bin"; PreparedStatement pstmt=con.preparestatement (SQL); /** 3. pstmt execute query, get resultset*/ResultSet rs=Pstmt.executequery (); /** 4. Get column data called data in RS*/        if(Rs.next ()) {blob blob= Rs.getblob ("Data"); /** Turn blob into a file on your hard drive! */            /** 1. Get input Stream object through BLOB * 2. Create an output stream object yourself * 3. Write data from the input stream to the output stream*/InputStream in=Blob.getbinarystream (); OutputStream out=NewFileOutputStream ("C:/lgfw.mp3");        Ioutils.copy (in, out); }    }}

Big Data-Save MP3 to database and read out "Dark Horse programmer _ ultra-comprehensive javaweb video tutorial Vedio" Day17

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