java implementation inserts mysql binaries blob types encounters problems and fixes

The first is to prepare for the database establishment:
We will set the place 2-base field to Blob type, and select the appropriate Blob type according to the size of the file. 1 is the size of the 2-base file that each Blob type can hold
Four BLOB types of MySQL
Type size (in bytes)
TinyBlob maximum 255
65 K Blob biggest
16 M MediumBlob biggest
4 G LongBlob biggest
1. The following is the specific operation code:

/** 
* 
*  the 2 A binary file ( the 2 A base file can be a local hard disk path or it can be 1 Network path ) Stored in database  
* create date:2009-5-13 author:Administrator 
* 
* @param file 
*  It can be a local file or a network file  
* @param conn 
*/ 
public void saveBinary(String file, Connection conn) { 
//  Pay attention to 2 The classes used when the base file is written to the database, and the class wrapper conversion process  
File f = null; 
if (file.toLowerCase().contains("http:")) 
f = DownLoadWithUrl.downLoadFile(file); 
else 
f = new File(file); 
if (f != null) { 
try { 
InputStream is = new FileInputStream(f); 
PreparedStatement ps = conn 
.prepareStatement("insert into bankVoice(name,text) values (?,?)"); 
ps.setString(1, file); 
int i = is.available(); 
ps.setBinaryStream(2, is, is.available()); 
ps.executeUpdate(); 
System.out.println("2 Base file inserted successfully "); 
ps.clearParameters(); 
ps.close(); 
is.close(); 
} catch (Exception e) { 
e.printStackTrace(); 
System.out.println("2 An exception occurred while the base file was being inserted "); 
} 
} 
} 

Note that the following exceptions will occur during operation, so we only need to do 1 setting: take my local as an example: go to D:\ MySql5.0 \ mysql-5.0.51 b-win32 directory, the following files can be seen: my-large.ini, my-small.ini, my-medium.ini, my-huge.ini
We simply change the configuration item in the ini file that the mysql service now loads: max_allowed_packet to 16M
max_allowed_packet = 16M the default is 1M let's change to 16M and then restart the mysql server so that the following exception does not occur.

com.mysql.jdbc.PacketTooBigException: Packet for query is too large (1048587 > 1047552). You can change this value on the server by setting the max_allowed_packet' variable. 
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2632) 
at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2618) 
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1551) 
at com.mysql.jdbc.ServerPreparedStatement.storeStream(ServerPreparedStatement.java:2180) 
at com.mysql.jdbc.ServerPreparedStatement.serverLongData(ServerPreparedStatement.java:1199) 
at com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement.java:1004) 
at com.mysql.jdbc.ServerPreparedStatement.executeInternal(ServerPreparedStatement.java:670) 
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1159) 
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1076) 
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1061) 
at SaveBinaryToDB.SaveBinaryToDB.saveBinary(SaveBinaryToDB.java:33) 
at SaveBinaryToDB.SaveBinaryToDB.main(SaveBinaryToDB.java:17) 
/** 
*  Read from the database 2 A binary file  create date:2009-5-13 author:Administrator 
* 
* @param file 
* @param conn 
*/ 
public void getBinary(String file, Connection conn) { 
//  Pay attention to 2 The classes used when the base file is read from the database, and the wrapper transformation process for the classes  
try { 
PreparedStatement ps = conn 
.prepareStatement("select text from bankVoice where name=?"); 
ps.setString(1, file); 
Blob blob = null; 
ResultSet rs = ps.executeQuery(); 
if (rs.next()) { 
blob = (Blob) rs.getBlob("text"); 
} 
FileOutputStream fos = new FileOutputStream("D:\\test1.mp3"); 
fos.write(blob.getBytes(1, (int) blob.length())); 
System.out.println("2 Base file successful "); 
ps.clearParameters(); 
ps.close(); 
fos.close(); 
} catch (Exception e) { 
e.printStackTrace(); 
System.out.println("2 An exception occurred while reading the base file "); 
} 
} 

package SaveBinaryToDB;

/** 
*  The function of this procedure to achieve network download  
*  The specified url Download the files to your local hard drive  
* 
*/ 
import java.io.*; 
import java.net.*; 
/** 
* @todo  Images will be captured online ,mp3 Wait for the file to be stored locally  
* 
* @version 1.0 
*/ 
public class DownLoadWithUrl { 
public static File downLoadFile(String fromUrl) { 
URL url; 
File file = null; 
try { 
// url = new 
// URL("http://count.koubei.com/showphone/showphone.php?f=jpg&w=96&h=10&bc=255,255,255&fc=0,0,0&fs=10&fn=arial&phone=NzMwNzIyNTE1%236aWCXtTNZYkxASrj"); 
url = new URL(fromUrl); 
URLConnection uc = url.openConnection(); 
InputStream is = uc.getInputStream(); 
//  According to the type of download file, the corresponding file name  
file = new File("D:\\forever.mp3"); 
FileOutputStream out = new FileOutputStream(file); 
/* 
*  So is the one in the comment 1 A way to write to a file, but it is usually downloaded mp3 Or better than mp3 Smaller pictures  
*  Wait for these files to use this buffered method to write the file is relatively slow, so small file download usually use the following   The method of writing a file is ok  // byte[] b = new 
* byte[102400*3]; // int size = 0; // // while ((size = is.read(b)) != 
* -1) { // out.write(b, 1, size); // // } 
*/ 
int i = 0; 
while ((i = is.read()) != -1) { 
out.write(i); 
} 
out.flush(); 
is.close(); 
} catch (Exception e) { 
// TODO Auto-generated catch block 
e.printStackTrace(); 
} 
return file; 
} 
/** 
*  Deletes the file for the specified path on the local disk  create date:2009-5-13 author:Administrator 
* 
* @param file 
*/ 
public static void delFile(String file) { 
File f = new File(file); 
if (f.exists()) 
f.delete(); 
System.out.println(file + " It has been deleted "); 
} 
public static void main(String[] args) { 
// delFile("D:\\forever.mp3"); 
downLoadFile(""); 
} 
}