Question

如何在Oracle中使用Java存储过程(详解)

Answer 1

其实，这篇短文，我早就应该写了。因为，java存储过程今后在各大数据库厂商中越来越流行，功能也越来越强大。这里以Oracle为例，介绍一下java存储过程的具体用法。 iihero on csdn) 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o




其实，这篇短文，我早就应该写了。因为，java存储过程今后在各大数据库厂商中越来越流行，功能也越来越强大。这里以Oracle为例，介绍一下java存储过程的具体用法。iihero on csdn)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 "" 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 /过程已创建。SQL> set serveroutput onSQL> call javademo1();调用完成。SQL> call dbms_java.set_output(5000);调用完成。SQL> call javademo1();hello, java demo1调用完成。SQL> call javademo1();hello, java demo1调用完成。
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> grant create any directory to scott;授权成功。SQL> conn scott/tiger@iihero.oracledb已连接。SQL> create or replace directory test_dir as 'd:/oracle';目录已创建。SQL> create or replace java class using bfile(test_dir, 'OracleJavaProc.CLASS') 2 /Java 已创建。SQL> create or replace procedure testjavaproc as language java name 'OracleJavaProc.main(java.lang.String[])'; 2 /过程已创建。SQL> call testjavaproc();调用完成。SQL> execute testjavaproc;PL/SQL 过程已成功完成。SQL> set serveroutput on size 5000SQL> call dbms_java.set_output(5000);调用完成。SQL> execute testjavaproc;It's a Java Oracle procedure.
3. 我推荐的一种方法，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/tiger@iihero.oracledb -v -resolve OracleJavaProc.javaarguments: '-u' 'scott/tiger@iihero.oracledb '-v' '-resolve' 'OracleJavaProc.java'creating : source OracleJavaProcloading : source OracleJavaProcresolving: source OracleJavaProc
查询一下状态：
连接到:Oracle9i Enterprise Edition Release 9.2.0.1.0 - ProductionWith the Partitioning, OLAP and Oracle Data Mining optionsJServer Release 9.2.0.1.0 - ProductionSQL> SELECT object_name, object_type, status FROM user_objects WHERE object_type LIKE 'JAVA%';OBJECT_NAME--------------------------------------------------------------------------------OBJECT_TYPE STATUS------------------------------------ --------------OracleJavaProcJAVA CLASS VALIDOracleJavaProcJAVA SOURCE VALID
测试一下存储过程：
SQL> create or replace procedure add_salgrade(id number, losal number, hisal number) as language java name 'OracleJavaProc.addSalGrade(int, int, int)'; 2 /过程已创建。SQL> set serveroutput on size 2000SQL> 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 OracleJavaProcD:/tiger@iihero.oracledbeclipse3.1workspacedbtest>loadjava -u scott -v -resolve OracleJavaProc/tiger@iihero.oracledb.javaarguments: '-u' 'scott/tiger@iihero.oracledb' '-v' '-resolve' 'OracleJavaProc.java'creating : source OracleJavaProcloading : source OracleJavaProcresolving: source OracleJavaProc
后边的应用示例：
SQL> create or replace function query_hisal(grade number) return number as language java name 'OracleJavaProc.getHiSal(int) return int'; 2 /函数已创建。SQL> set serveroutput on size 2000SQL> call dbms_java.set_output(2000);调用完成。SQL> select query_hisal(5) from dual;QUERY_HISAL(5)-------------- 9999
全文完！用法个人见解：不要手动drop java source, 不要手动drop procedure。