JPA example to backup the packages/tables of oracle database

I performed the backup task through JDBC originally, however, found it's very easy to switch to JPA.

It's impressed that it's very easy to use JPA2/Hibernate to backup database or generate the package files.
JPA2/Hibernate only brings a minor performance impact (can be ignored). It's much easier to program and the program is more elegant.
The cost is to 1) introduce additional jars 2) study JPA/Hibernate

To run the example, need persistence.xml and *.jar

import

java.io.BufferedWriter;

import

java.io.FileOutputStream;

import

java.io.IOException;

import

java.io.OutputStreamWriter;

import

java.util.List;

import

javax.persistence.EntityManager;

import

javax.persistence.EntityManagerFactory;

import

javax.persistence.Persistence;

public

class PackageFilesGenerator

{

//do not include the schema prefix

private static final String NO_SCHEMA = "BEGIN DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'EMIT_SCHEMA', false); END;";

//make it look pretty

private static final String PRETTY = "BEGIN DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'PRETTY', true); END;";

//don't include the physical properties

private static final String NO_PHYSICAL_PROP = "BEGIN DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'PHYSICAL_PROPERTIES', false); END;";

//don't include the segment attributes

private static final String NO_SEGMENT_PROP = "BEGIN DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SEGMENT_ATTRIBUTES', false); END;";

//include a sql terminator for each statement

private static final String SQL_TERMINATOR = "BEGIN DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SQLTERMINATOR', true); END;";

private static final String SQL_OJBECTS = "select object_name from user_objects where object_type = 'PACKAGE' and instr(object_name,'TEST')=0 order by 1";

@SuppressWarnings("unchecked")

public static void main( String[] args ) throws IOException

{

long start = System.currentTimeMillis();

EntityManagerFactory emf = Persistence.createEntityManagerFactory(

"DEV");

EntityManager em = emf.createEntityManager();

em.getTransaction().begin();

em.createNativeQuery(

NO_SCHEMA).executeUpdate();

em.createNativeQuery(

PRETTY).executeUpdate();

em.createNativeQuery(

NO_PHYSICAL_PROP).executeUpdate();

em.createNativeQuery(

NO_SEGMENT_PROP).executeUpdate();

em.createNativeQuery(

SQL_TERMINATOR).executeUpdate();

List<String> objectNames = (List<String>)em.createNativeQuery(

SQL_OJBECTS).getResultList();

for(String objectName:objectNames){

String ddlSpec = getDDL(em,

"PACKAGE_SPEC",objectName);

write(

"pks."+objectName.toLowerCase()+".sql",ddlSpec);

String ddlBody = getDDL(em,

"PACKAGE_BODY",objectName);

write(

"pkb."+objectName.toLowerCase()+".sql",ddlBody);

}

em.getTransaction().commit();

em.close();

long end = System.currentTimeMillis();

System.

out.printf("Done. Spent %d secs.", (end - start) / 1000);

}

private static String getDDL(EntityManager em,String type,String objectName){

String sql =

"select DBMS_METADATA.GET_DDL('"+"PACKAGE_SPEC"+"','"+objectName+"') from DUAL";

return em.createNativeQuery(sql).getSingleResult().toString();

}

public static void write(String fileStr,String content) throws IOException{

BufferedWriter writer =

new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileStr)));

writer.append(content);

writer.newLine();

writer.close();

}

}