oracle调用java

其它语言的函数的调用

java函数调用

 

在oracle数据库建立一个java资源，也可以用loadjava命令装载其它的java类或者jar

 

create or replace and compile java sourcenamed mytestjava as
public class Factorial {
public static int calcFactorial (int n) {
if (n == 1) return 1;
else return n * calcFactorial (n - 1) ;
}
}

 

建立一个映射函数

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

 

这是一个极其简单的例子，但是有了这样的功能，你可以调用外部的任何外部命令，也可以与其他任何外部数据库数据文件进行通讯了

 

 

下面一个例子，实现在数据库内调用任何外部命令的功能

 

CREATE OR REPLACE AND COMPILE JAVA SOURCE NAMED "Host" AS
import 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;
  }
};

 

 

在调用外部程序之前，必须授权给数据库用户相应的权限

 

-- 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;

 

建立映射过程

CREATE OR REPLACE PROCEDUREhost_command (p_command  IN  VARCHAR2)

AS LANGUAGEJAVA

NAME'Host.executeCommand (java.lang.String)';

 

测试

DECLARE

 l_output DBMS_OUTPUT.chararr;

 l_lines  INTEGER := 1000;

BEGIN

 DBMS_OUTPUT.enable(1000000);

 DBMS_JAVA.set_output(1000000);

 host_command('dir g:\');  --执行显示目录的命令

 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;

 

 原创文章，如果转载，请标注作者：田文  CSDN地址：http://blog.csdn.net/tiwen818