Oracle 8.1.5 introduced the ability to choose Java as a language to implement a stored procedure.
One of our customers required the following functionalities from within an Oracle database:
- Running an operating system command
- The ability to copy a file
- Listing all of the files in a given directory
These things are missing in UTL_FILE.
PL/SQL cannot do this – Java can quite easily.
Here is how (I have tested this on an Oracle 8.1.7 and 10.1.0.2.0):
I created a collection type and a package for these functionalities:
create or replace type STRARRAY as table of varchar2(255) /
This type is used for holding a Java object (of oracle.sql.ARRAY[]).
CREATE OR REPLACE PACKAGE UTIL AS FUNCTION RUN_CMD(p_cmd IN VARCHAR2) RETURN NUMBER; PROCEDURE COPY_FILE(p_srcFile IN VARCHAR2, p_destDir IN VARCHAR2); PROCEDURE GET_DIR_LIST(p_dir IN VARCHAR2, p_dirList OUT STRARRAY); END UTIL; /
CREATE OR REPLACE PACKAGE BODY UTIL AS FUNCTION RUN_CMD(p_cmd IN VARCHAR2) RETURN NUMBER AS LANGUAGE JAVA NAME 'nl.amis.util.RunCmd.runThis(java.lang.String) return int'; PROCEDURE COPY_FILE(p_srcFile IN VARCHAR2, p_destDir IN VARCHAR2) AS LANGUAGE JAVA NAME 'nl.amis.util.FileCopy.copy(java.lang.String, java.lang.String)'; PROCEDURE GET_DIR_LIST(p_dir IN VARCHAR2, p_dirList OUT STRARRAY) AS LANGUAGE JAVA NAME 'nl.amis.util.DirList.getList(java.lang.String, oracle.sql.ARRAY[])'; END UTIL; /
As you can see, Java methods (see the implementation below) are wrapped into stored procedures or functions.
We can just use SQL*PLUS to load Java code straight into the database, have it compiled into byte code and stored for us.
There is no need for an external compiler, no JDK installs – just a SQL CREATE OR REPLACE AND COMPILE JAVA SOURCE NAMED… statement:
Running an operating system command:
CREATE OR REPLACE AND COMPILE JAVA SOURCE NAMED "RunCmd" AS
package nl.amis.util;
import java.io.*;
public class RunCmd
{
private static void pass( java.lang.String p_in,
java.lang.String[] p_out )
{
if ( p_in != null ){
p_out[ 0 ] = p_in.toUpperCase();
}
}
public static int runThis(String cmd)
{
Runtime rt = Runtime.getRuntime();
int rc = -1;
String[] args = new String[ 4096 ];
pass(cmd, args);
try
{
Process p = rt.exec(args[ 0 ]);
int bufSize = 4096;
BufferedInputStream bis =
new BufferedInputStream(p.getInputStream(), bufSize);
int len;
byte buffer[] = new byte[bufSize];
// Echo back what the program spit out
while ((len = bis.read(buffer, 0, bufSize)) != -1)
System.out.write(buffer, 0, len);
rc = p.waitFor();
}
catch (Exception e)
{
e.printStackTrace();
rc = -1;
}
return rc;
}
}
/
We have to grant as SYS the appropriate Java permissions to the schema storing this java source (here GREGORY), since the database will take care of the security:
BEGIN dbms_java.grant_permission( 'GREGORY', SYS:java.io.FilePermission', 'C:WINDOWSSYSTEM32CMD.EXE', 'execute' ); dbms_java.grant_permission( 'GREGORY', 'SYS:java.lang.RuntimePermission', '*', 'writeFileDescriptor' ); END; /
The first privilege allows us to run a very specific program. If we put * in place of the program name, we can run anything.
The second allows us run-time to produce output.
Here we must use a *, as we do not know what output might be created (stdout for example).
Next, a procedure to call UTIL.RUN_CMD:
CREATE OR REPLACE PROCEDURE RC(
P_CMD IN VARCHAR2)
AS
X NUMBER;
BEGIN
X := UTIL.RUN_CMD (P_CMD);
IF (X <> 0)
THEN
RAISE PROGRAM_ERROR;
END IF;
END RC;
/
Now, we will see how this works:
SQL> set serveroutput on size 1000000
SQL> exec dbms_java.set_output(1000000)
PL/SQL procedure successfully completed.
SQL> exec rc('C:WINDOWSsystem32cmd.EXE /c dir C:Gregory')
Volume in drive C has no label.
Volume Serial Number is 5C82-7765
Directory of C:GREGORY
02/07/2005 04:19 PM <dir> .
02/07/2005 04:19 PM <dir> ..
11/20/2003 11:51 AM 411 call_process_trillium
11/13/2003 09:49 AM 485,758 Docs.zip
12/09/2003 02:07 PM 1,380 GG-data-sources.xml
12/09/2003 05:12 PM 12,599,247 GG-oc4j-app.log
12/09/2003 02:07 PM 422 GG-oc4j-app.xml
11/04/2003 02:00 PM 634 GG.jws
11/10/2003 05:08 PM 13,473 process_trillium.sql
11/07/2003 05:08 PM 93,512 rdc.zip
11/04/2003 02:06 PM 35,851 rdplog.zip
11/14/2003 03:01 PM 3,369,686 RDP_DEV.zip
11/17/2003 10:22 AM 1,126 test.html
11/17/2003 10:21 AM 1,242 test.html.bak
11/04/2003 01:59 PM 11,008 TestAU.java
11/13/2003 09:49 AM 48 vssver.scc
14 File(s) 16,613,798 bytes
2 Dir(s) 8,372,465,664 bytes free
PL/SQL procedure successfully completed.
Copying a file:
CREATE OR REPLACE AND COMPILE JAVA SOURCE NAMED "FileCopy" AS
package nl.amis.util;
import java.io.*;
public class FileCopy{
public static void copy(String srcFile, String destDir) {
File source = new File(srcFile);
File dest = new File(destDir);
File cpDestFile = null;
try {
if (dest.isDirectory()) {
if(source.isFile()) {
System.out.println("File name = " + source.getName());
System.out.println("File name dest = " + dest.getPath() );
System.out.println("File name cpDestFile = " + dest.getPath() + File.separator + source.getName());
cpDestFile = new File(dest.getPath() + File.separator + source.getName());
}
else {
System.out.println("Directory or File Not Found");
return;
}
}
BufferedInputStream br = new BufferedInputStream (new FileInputStream (source));
BufferedOutputStream bw = new BufferedOutputStream (new FileOutputStream (cpDestFile));
int read = 0;
while((read = br.read()) != -1) {
//System.out.println((char)read);
bw.write(read);
}
br.close();
bw.close();
}
catch (FileNotFoundException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
}
}
/
We also have to grant as SYS the appropriate Java permissions to GREGORY when copying ‘C:\temp\xmltool javadoc.zip’
to ‘C:\Gregory’
BEGIN dbms_java.grant_permission( 'GREGORY', 'SYS:java.io.FilePermission', 'C:Gregory', 'read' ); dbms_java.grant_permission( 'GREGORY', 'SYS:java.io.FilePermission', 'C:tempxmltool javadoc.zip', 'read' ); dbms_java.grant_permission( 'GREGORY', 'SYS:java.io.FilePermission', 'C:Gregoryxmltool javadoc.zip', 'write' ); END; /
Ready to test it:
SQL> set serveroutput on size 1000000
SQL> exec dbms_java.set_output(1000000)
PL/SQL procedure successfully completed.
SQL> exec UTIL.COPY_FILE('C:tempxmltool javadoc.zip', 'C:Gregory')
File name = xmltool javadoc.zip
File name dest = C:Gregory
File name cpDestFile = C:Gregoryxmltool javadoc.zip
PL/SQL procedure successfully completed.
Getting a directory listing:
CREATE OR REPLACE AND COMPILE JAVA SOURCE NAMED "DirList" AS
package nl.amis.util;
import java.io.*;
import java.sql.*;
import oracle.sql.*;
import oracle.jdbc.driver.*;
public class DirList {
public static void getList(String directory, oracle.sql.ARRAY[] listArray) throws java.sql.SQLException,IOException{
File path = new File(directory);
String[] list = path.list();
Connection conn = new OracleDriver().defaultConnection();
ArrayDescriptor descr =
ArrayDescriptor.createDescriptor( "STRARRAY", conn ); //"STRARRAY" is SQL type name (table of varchar2(255))
listArray[ 0 ] = new ARRAY( descr, conn, list );
}
}
/
Here also the grant (as SYS) on a specific directory we want a listing of:
BEGIN dbms_java.grant_permission( 'GREGORY', 'SYS:java.io.FilePermission', 'C:temp', 'read' ); END; /
A test program:
SQL> set serveroutput on size 1000000
SQL> exec dbms_java.set_output(1000000)
PL/SQL procedure successfully completed.
SQL> DECLARE
2 vArray STRARRAY := STRARRAY ();
3 BEGIN
4 UTIL.GET_DIR_LIST('C:temp', vArray);
5 DBMS_OUTPUT.PUT_LINE(CHR(09));
6 DBMS_OUTPUT.PUT_LINE('Directory listing of C:temp:');
7 DBMS_OUTPUT.PUT_LINE(CHR(09));
8 FOR i IN 1..vArray.COUNT LOOP
9 DBMS_OUTPUT.PUT_LINE(vArray(i));
10 END LOOP;
11 END;
12 /
Directory listing of C:temp:
274326.pdf
275195.pdf
DEPT.csv
edvpln502f.fmb
EMP.csv
emp_dept.dmp
f90jdapi.zip
f90upgrade.zip
fma
forms9icstowebmigration.pdf
forms_upgrade_reference.pdf
jdapi javadoc.zip
jdapi.properties
jdapiTools.zip
jdev9052.zip
log
sqlnet.log
test.log
xmltool javadoc.zip
PL/SQL procedure successfully completed.
Resource:
Chapter 19 of ‘Expert One-on-One Oracle’ by Thomas Kyte