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

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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