Java and MySQL database large text and binary operations

1. Text (clob)

In MySQL, the maximum varchar value is 65535 bytes. If the value exceeds this range, set it to text.

Longtext can be up to 4 GB

Store text // define SQL statement string SQL = "insert into clob (File) value (?) ";

Preparedstatement PS = conn. preparestatement (SQL );

File file =NewFile ("Res/clobdemo. Java ");

Reader reader =NewFilereader (File );

PS. setcharacterstream (1, reader ,(Int) File. Length ());

Ps.exe cuteupdate ();

// Close the stream.

Reader. Close ();

Read text

String SQL = "SELECT FILE from clob ";

Preparedstatement PS = conn. preparestatement (SQL );

Resultset Rs cmdps.exe cutequery ();

If(Rs. Next ()){

Reader reader = Rs. getcharacterstream (INT columnindex );

// This reader is the stream that reads data from the database and operates this stream to read data.

Bufferedreader BR =NewBufferedreader (R );

Bufferedwriter BW =NewBufferedwriter (NewFilewriter (

"Res/new.txt "));

String S = "";

 While(S = Br. Readline ())! =Null){

Bw. Write (S + "\ n ");

}

Bw. Flush ();

BR. Close ();

R. Close ();

Bw. Close ();

}

2. blob

Blob is used to store large binary data segments, such as the sample, audio, and video. longblob. the maximum size is 4 GB.

Storage blob

Preparedstatement PS = conn. preparestatement ("insert into big_binary (File) values (?) ");

File file =NewFile ("src/CN/itcast/jdbc1/clob_blob/img_0007.jpg ");

Inputstream in =NewFileinputstream (File );

PS. setbinarystream (1, In ,(Int) File. Length ());

Ps.exe cuteupdate ();

Read blob

Preparedstatement PS = conn. preparestatement ("select filefrom big_binary ");

Resultset Rs cmdps.exe cutequery ();

If(Rs. Next ()){

Inputstream in = Rs. getbinarystream (1 );

// This inputstream is the stream that reads data from the database. You can use this stream to read data.

File file = new file ("Res/newgirl.jpg ");
Fileoutputstream Fos = new fileoutputstream (File );
Int num = in. Available ();
Byte buffer [] = new byte [num];
While (in. Read (buffer, 0, num )! =-1 ){
FOS. Write (buffer );
}
System. Out. println ("Left ");
In. Close ();
FOS. Close ();

}