Oracle calls Java

Function calls in other languages

Java function call

 

Create a Java resource in the Oracle database, or use the loadjava command to load other Java classes or jar

 

Create or replace and compile Java sourcenamed mytestjava
Public class factorial {
Public static int calcfactorial (int n ){
If (n = 1) return 1;
Else return N * calcfactorial (n-1 );
}
}

 

Create a ing Function

Create or replace function plstojavafac_fun
(N number)
Return number
As
Language Java
Name 'factorial. calcfactorial (INT) return int ';

 

Selectplstojavafac_fun (4) from dual

----

24

 

This is an extremely simple example, but with this function, you can call any external commands or communicate with any other external database data files.

 

 

The following example shows how to call any external commands in the database.

 

CREATE OR REPLACE AND COMPILE JAVA SOURCE NAMED "Host" ASimport java.io.*;public class Host {  public static void executeCommand(String command) {    try {      String[] finalCommand;      if (isWindows()) {        finalCommand = new String[4];        // Use the appropriate path for your windows version.        finalCommand[0] = "C:\\windows\\system32\\cmd.exe";  // Windows XP/2003        //finalCommand[0] = "C:\\winnt\\system32\\cmd.exe";  // Windows NT/2000        finalCommand[1] = "/y";        finalCommand[2] = "/c";        finalCommand[3] = command;      }      else {        finalCommand = new String[3];        finalCommand[0] = "/bin/sh";        finalCommand[1] = "-c";        finalCommand[2] = command;      }        final Process pr = Runtime.getRuntime().exec(finalCommand);      pr.waitFor();      new Thread(new Runnable(){        public void run() {          BufferedReader br_in = null;          try {            br_in = new BufferedReader(new InputStreamReader(pr.getInputStream()));            String buff = null;            while ((buff = br_in.readLine()) != null) {              System.out.println("Process out :" + buff);              try {Thread.sleep(100); } catch(Exception e) {}            }            br_in.close();          }          catch (IOException ioe) {            System.out.println("Exception caught printing process output.");            ioe.printStackTrace();          }          finally {            try {              br_in.close();            } catch (Exception ex) {}          }        }      }).start();        new Thread(new Runnable(){        public void run() {          BufferedReader br_err = null;          try {            br_err = new BufferedReader(new InputStreamReader(pr.getErrorStream()));            String buff = null;            while ((buff = br_err.readLine()) != null) {              System.out.println("Process err :" + buff);              try {Thread.sleep(100); } catch(Exception e) {}            }            br_err.close();          }          catch (IOException ioe) {            System.out.println("Exception caught printing process error.");            ioe.printStackTrace();          }          finally {            try {              br_err.close();            } catch (Exception ex) {}          }        }      }).start();    }    catch (Exception ex) {      System.out.println(ex.getLocalizedMessage());    }  }    public static boolean isWindows() {    if (System.getProperty("os.name").toLowerCase().indexOf("windows") != -1)      return true;    else      return false;  }};
 
 
Before calling an external program, you must grant the corresponding permissions to the database user.
 
-- Created on 2007-9-13 by tiwen
Declare
Begin
Dbms_java.grant_permission ('tiwen', 'java. Io. filepermission', '<all files>', 'read, write, execute, delete ');
Dbms_java.grant_permission ('tiwen', 'sys: Java. Lang. runtimepermission', 'writefiledescriptor ','');
Dbms_java.grant_permission ('tiwen', 'sys: Java. Lang. runtimepermission', 'readfiledescriptor ','');
End;
 
Ing Process
Create or replace procedurehost_command (p_command in varchar2)
As languagejava
Name'host.exe cutecommand (Java. Lang. String )';
 
Test
Declare
Rochelle output dbms_output.chararr;
Rochelle lines INTEGER: = 1000;
Begin
Dbms_output.enable (1000000 );
Dbms_java.set_output (1000000 );
Host_command ('dir G: \ '); -- execute the command to display the Directory
Dbms_output.get_lines (l_output, l_lines );
For I in 1 .. l_lines Loop
Dbms_output.put_line (l_output (I ));
NULL;
End loop;
End;
 
 Original article, if reproduced, please mark the author: Tian Wen csdn address: http://blog.csdn.net/tiwen818