//VM配置:256M-512M

//通过lo_import(‘文件路径’)函数向oid字段插入二进制文件，通过(不会内存溢出)。

/**

*

* @author Liu Yuanyuan

*/

private void insertOid()

{

String driver = "org.postgresql.Driver";//"com.highgo.jdbc.Driver";//192.168.100.125

String url = "jdbc:postgresql://" + "127.0.0.1" + ":" + "5866" + "/" + "db1";

Connection conn = null;

Statement stmt = null;

try

{

Class.forName(driver);

System.out.println("success find class");

conn = DriverManager.getConnection(url, "highgo", "hg");

System.out.println("success connect");

stmt = conn.createStatement();

//driectly insert

String f = "d:/1.jpg";

stmt = conn.prepareStatement("INSERT INTO oidtable VALUES (11, lo_import(\'"+f+"\'))");

//or by update

//String f = "d://2.jpg";

//PreparedStatement ps = conn.prepareStatement("update oidtable set obj = lo_import(\'"+f+"\') where id=?");

//ps.setInt(1,11);

ps.executeUpdate();

}

catch(Exception ex)

{

ex.printStackTrace(System.out);

}

finally

{

try

{

if(stmt!=null)

stmt.close();

if(conn!=null)

conn.close();

}

catch(Exception ex)

{

ex.printStackTrace(System.out);

}

finally

{

System.out.println("finally");

}

}

}

//VM配置:256M-512M

//直接通过setLong()向oid插入1GB的文件，通过(2分钟之内插入完毕);

public void insertOid()

{

Connection conn = null;

PreparedStatement ps = null;

try

{

String driver = "org.postgresql.Driver";

String url = "jdbc:postgresql://" + "127.0.0.1" + ":" + "5432" + "/" + "db1";

Class.forName(driver);

System.out.println("class");

conn = DriverManager.getConnection(url, "postgres", "pg");

System.out.println("connect");

// All LargeObject API calls must be within a transaction block

conn.setAutoCommit(false);

// Get the Large Object Manager to perform operations with

LargeObjectManager lobj = ((org.postgresql.PGConnection) conn).getLargeObjectAPI();

// Create a new large object

long oid = lobj.createLO(LargeObjectManager.READ | LargeObjectManager.WRITE);

// Open the large object for writing

LargeObject obj = lobj.open(oid, LargeObjectManager.WRITE);

//Now open the file

File file = new File("d://1.jpg");

FileInputStream fis = new FileInputStream(file);

// Copy the data from the file to the large object

byte buf[] = new byte[2048];

int s, tl = 0;

while ((s = fis.read(buf, 0, 2048)) > 0)

{

obj.write(buf, 0, s);

tl += s;

}

// Close the large object

obj.close();

// Now insert the row into imageslo

ps = conn.prepareStatement("INSERT INTO lob.oidtable VALUES (?, ?)");

ps.setInt(1, 1);

ps.setLong(2, oid);

ps.executeUpdate();

fis.close();

// Finally, commit the transaction.

mit();

conn.setAutoCommit(true);

}

catch (Exception ex)

{

ex.printStackTrace(System.out);

}

finally

{

try

{

if (ps != null)

{

ps.close();

}

if(conn != null)

{

conn.close();

}

System.out.println("close all");

}

catch (SQLException ex)

{

ex.printStackTrace(System.out);

}

}

}

//VM配置:256M-512M

//直接通过getLong()从oid取出1GB的文件，通过(2分钟之内取出完毕)；

public void getBinaryFile()

{

Connection conn = null;

PreparedStatement ps = null;

ResultSet rs = null;

try

{

String driver = "org.postgresql.Driver";

String url = "jdbc:postgresql://" + "127.0.0.1" + ":" + "5866" + "/" + "db1";

Class.forName(driver);

System.out.println("class");

conn = DriverManager.getConnection(url, "highgo", "hg");

System.out.println("connect");

// All LargeObject API calls must be within a transaction block

conn.setAutoCommit(false);

// Get the Large Object Manager to perform operations with

LargeObjectManager lobj = ((org.postgresql.PGConnection) conn).getLargeObjectAPI();

ps = conn.prepareStatement("SELECT obj FROM lob.oidtable WHERE id = ?");

ps.setInt(1, 1);

rs = ps.executeQuery();

while (rs.next())

{

// Open the large object for reading

long oid = rs.getLong(1);

LargeObject obj = lobj.open(oid, LargeObjectManager.READ);

// Read the data

// obj.read(buf, 0, obj.size());//its read method

// Do something with the data read here

//for example:load the file to disk

OutputStream ops = new FileOutputStream(new File("d:\\111.jpg"));

byte buf[] = new byte[1024];//当文件很大时，用obj.size()将内存溢出，所以可以自定义一个合适的值

for (int i; (i = obj.read(buf, 0,1024)) > 0;)

{

ops.write(buf, 0, i);

ops.flush();

}

// Close the object

obj.close();

ops.close();

}

// Finally, commit the transaction

mit();

}

catch (Exception ex)

{

ex.printStackTrace(System.out);

}

finally

{

try

{

if (rs != null)

{

rs.close();

}

if (ps != null)

{

ps.close();

}

if(conn != null)

{

conn.close();

}

System.out.println("close all");

}

catch (SQLException ex)

{

ex.printStackTrace(System.out);

}

}

}