存储过程中 调用 Java

一、如何创建java存储过程？
通常有三种方法来创建java存储过程。

1. 使用oracle的sql语句来创建：

  e.g. 使用create or replace and compile java source named "<name>" as
       后边跟上java源程序。要求类的方法必须是public static的，才能用于存储过程。

SQL> create or replace and compile java source named "javademo1"
  2  as
  3  import java.sql.*;
  4  public class JavaDemo1
  5  {
  6  public static void main(String[] argv)
  7  {
  8    System.out.println("hello, java demo1");
  9  }
10  }
11  /

Java 已创建。

SQL> show errors java source "javademo1"
没有错误。

SQL> create or replace procedure javademo1
  2  as
  3  language java name ''JavaDemo1.main(java.lang.String[])'';
  4  /

SQL> set serveroutput on
SQL> call dbms_java.set_output(5000);
SQL> execute  javademo1;
SQL> call javademo1();
hello, java demo1


2. 使用外部class文件来装载创建
   e.g. 这里既然用到了外部文件，必然要将class文件放到oracle Server的某一目录下边。


public class OracleJavaProc
{
    public static void main(String[] argv)
    {
        System.out.println("It''s a Java Oracle procedure.");
    }
}

SQL> conn system/manager
SQL> grant create any directory to scott;
SQL> conn scott/tiger
SQL> create or replace directory test_dir as 'd:\'; 目录已创建。
SQL> create or replace java class using bfile(test_dir,'TEST.CLASS') 2 / Java 已创建。
SQL> select object_name,object_type,STATUS from user_objects;
SQL> create or replace procedure test_java  as language java  name 'TEST.main(java.lang.String[])'; / 过程已创建。
SQL> set serveroutput on size 5000
SQL> call dbms_java.set_output(5000); 调用完成。
SQL> execute test_java;
  HELLO THIS iS A JAVA   ,PROCEDURE PL/SQL 过程已成功完成。
SQL> call test_java();
  HELLO THIS iS A JAVA PROCEDURE


3. 直接使用loadjava命令远程装载并创建。
先创建一个类, e.g.

import java.sql.*;
import oracle.jdbc.*;

public class OracleJavaProc ...{

   //Add a salgrade to the database.
   public static void addSalGrade(int grade, int losal, int hisal) ...{

      System.out.println("Creating new salgrade for EMPLOYEE...");

      try ...{
         Connection conn =
            DriverManager.getConnection("jdbc:default:connection:");

         String sql =
            "INSERT INTO salgrade " +
            "(GRADE,LOSAL,HISAL) " +
            "VALUES(?,?,?)";
         PreparedStatement pstmt = conn.prepareStatement(sql);
         pstmt.setInt(1,grade);
         pstmt.setInt(2,losal);
         pstmt.setInt(3,hisal);
         pstmt.executeUpdate();
         pstmt.close();
         }
      catch(SQLException e) ...{
         System.err.println("ERROR! Adding Salgrade: "
           + e.getMessage());
         }
   }
}

使用loadjava命令将其装载到服务器端并编译：

D:eclipse3.1workspacedbtest>loadjava -u scott/[e-mail] -v -resolve Or
acleJavaProc.java
arguments: ''-u'' ''scott/[e-mail] ''-v'' ''-resolve'' ''OracleJavaProc.java''
creating : source OracleJavaProc
loading  : source OracleJavaProc
resolving: source OracleJavaProc
查询一下状态：


连接到:
Oracle9i Enterprise Edition Release 9.2.0.1.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.1.0 - Production

SQL> SELECT object_name, object_type, status FROM user_objects WHERE object_type LIKE ''JAVA%'';

OBJECT_NAME
--------------------------------------------------------------------------------

OBJECT_TYPE                          STATUS
------------------------------------ --------------
OracleJavaProc
JAVA CLASS                           VALID

OracleJavaProc
JAVA SOURCE                          VALID
测试一下存储过程：


SQL> create or replace procedure add_salgrade(id number, losal number, hisal num
ber) as language java name ''OracleJavaProc.addSalGrade(int, int, int)'';
  2  /

过程已创建。

SQL> set serveroutput on size 2000
SQL> call dbms_java.set_output(2000);

调用完成。

SQL> execute add_salgrade(6, 10000, 15000);
Creating new salgrade for EMPLOYEE...

PL/SQL 过程已成功完成。

SQL> select * from salgrade where grade=6;

     GRADE      LOSAL      HISAL
---------- ---------- ----------
         6      10000      15000


二、如何更新你已经编写的java存储过程？ 

假如要往类OracleJavaProc里添加一个存储过程方法，如何开发？
正确的步骤应该是先dropjava, 改程序，再loadjava。

e.g.修改OracleJavaProc类内容如下：

import java.sql.*;
import oracle.jdbc.*;

public class OracleJavaProc ...{

   // Add a salgrade to the database.
   public static void addSalGrade(int grade, int losal, int hisal) ...{

      System.out.println("Creating new salgrade for EMPLOYEE...");

      try ...{
         Connection conn =
            DriverManager.getConnection("jdbc:default:connection:");

         String sql =
            "INSERT INTO salgrade " +
            "(GRADE,LOSAL,HISAL) " +
            "VALUES(?,?,?)";
         PreparedStatement pstmt = conn.prepareStatement(sql);
         pstmt.setInt(1,grade);
         pstmt.setInt(2,losal);
         pstmt.setInt(3,hisal);
         pstmt.executeUpdate();
         pstmt.close();
         }
      catch(SQLException e) ...{
         System.err.println("ERROR! Adding Salgrade: " 
           + e.getMessage());
         }
   }
   
   public static int getHiSal(int grade)
   ...{
    try ...{
        Connection conn =
          DriverManager.getConnection("jdbc:default:connection:");
        String sql = "SELECT hisal FROM salgrade WHERE grade = ?";
        PreparedStatement pstmt = conn.prepareStatement(sql);
        pstmt.setInt(1, grade);
        ResultSet rset = pstmt.executeQuery();
        int res = 0;
        if (rset.next())
        ...{
            res = rset.getInt(1);
        }
        rset.close();
        return res;
       }
    catch (SQLException e) 
    ...{
        System.err.println("ERROR! Querying Salgrade: " 
           + e.getMessage());
          return -1;
    }    
   }
      
}

如何更新呢？


D:eclipse3.1workspacedbtest>dropjava -u scott -v OracleJavaProc

D:/[e-mail]3.1workspacedbtest>loadjava -u scott -v -resolve Or
acleJavaProc/[e-mail]
arguments: ''-u'' ''scott/[e-mail]'' ''-v'' ''-resolve'' ''OracleJavaProc.java''
creating : source OracleJavaProc
loading  : source OracleJavaProc
resolving: source OracleJavaProc
后边的应用示例：


SQL> create or replace function query_hisal(grade number) return number as langu
age java name ''OracleJavaProc.getHiSal(int) return int'';
  2  /

函数已创建。

SQL> set serveroutput on size 2000
SQL> call dbms_java.set_output(2000);

调用完成。
SQL> select query_hisal(5) from dual;

QUERY_HISAL(5)
--------------
          9999