Java 存储过程 DB2 问题

Question

在我的课堂上，我在下面创建了简单的方法。这个类也有一个主要的功能。我正在从我的 DB2 存储过程中调用 getRes()。

public static void getRes() {
   System.out.println("Start");
   try{  
       Class.forName("com.ibm.db2.jcc.DB2Driver");  
       con = DriverManager.getConnection(  
       "jdbc:db2://url:50003/DB","user","Password");  
       Statement stmt=con.createStatement();  
       stmt.executeUpdate("INSERT INTO schema.TEST(ID) VALUES(1)"); 
   } catch(Exception e){
       System.out.println(e);
   } finally {
       if(con!=null) {
           try {
               con.close();
           } catch (SQLException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           }
       }
   }
   System.out.println("End");
}

我从 DB2 存储过程中调用这个函数。

CREATE OR REPLACE PROCEDURE schema.sp_TEST1()
 FENCED
 MODIFIES SQL DATA
EXTERNAL NAME 'connection.Connect.getRes()'
LANGUAGE JAVA
PARAMETER STYLE JAVA;

call schema.sp_TEST1()

此存储过程正在成功执行。但我怀疑我的方法是否执行。因为执行后测试表中没有任何条目。

以下是我部署此 jar 文件所遵循的步骤。 1. 从 Eclipse 中导出 jar。验证 jar 是否工作正常。 2. 执行调用 sqlj.install_jar()。验证 SYSIBM.SYSJARCONTENTS 中的安装。 3. 设置数据库服务器的类路径 导出 CLASSPATH=/home/db2inse5/sqllib/function/jar/SchemaName/JarName.jar 4.创建sp并调用sp。

预期输出是表测试中的一个条目。 但是虽然 sp 执行成功，但我没有得到预期的结果。

更新-20200423 我尝试提交数据库连接部分并将其替换为在数据库服务器中创建文件。这很有效，所以我可以确认从 SP 中正确调用了 jar 并且 jar 文件正常工作。但是上面的部分还没有解决

public static void getRes() {
    System.out.println("Start");
            File myObj = new File("/opt/filename.txt");
            myObj.createNewFile();
}

Answer 1

在Parameter style Java 例程中获取Connection 对象的方法错误。请阅读文档中的以下主题：Parameter style JAVA procedures.
您不能像在有序 jdbc 应用程序中那样获取它。不要使用Class.forName 电话。请改用以下内容：

con = DriverManager.getConnection("jdbc:default:connection");

也阅读Restrictions on external routines。不要在 Java 例程中使用 System.out.println(...)。

示例

在 db2 实例所有者的数据库服务器上执行此操作，无需任何修改。创建提到的目录结构。请确定，该 db2profile 来源于您的会话。

ExecAny.java：

package ru.ibm.db2udf;

import com.ibm.db2.jcc.DB2Diagnosable;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.logging.FileHandler;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.logging.SimpleFormatter;

public class ExecAny 
{
  /*
  --SQL statement for the class file placement w/o jar:
  --${DB2_HOME}/function/ru/ibm/db2udf/ExecAny.class

  --Uncomment the commented out line instead
  --if you placed this class into jar file and deployed it.

  CREATE OR REPLACE PROCEDURE EXEC_ANY 
  (
    SQL VARCHAR(4000)
  , LOG VARCHAR(512) DEFAULT NULL
  )
  LANGUAGE Java
  EXTERNAL NAME 'ru.ibm.db2udf.ExecAny.exec'
  --EXTERNAL NAME 'EXEC_ANY:ru.ibm.db2udf.ExecAny.exec'
  FENCED THREADSAFE
  MODIFIES SQL DATA
  PARAMETER STYLE JAVA;

  Usage:
    call exec_any('declare global temporary table test(i int) on commit preserve rows not logged', '/tmp/exec_any.txt');
    call exec_any('insert into session.test values 1', '/tmp/exec_any.txt');
    -- W/o logging
    call exec_any('insert into session.test values 2');

    select * from session.test;
  */
  public static void exec (String sql, String logfile) throws Exception 
  {
    Logger logger = null;
    FileHandler fhdl = null;
    Connection con = null;
    CallableStatement cst = null;
    try 
    {
      if (logfile != null && ! "".equals((logfile=logfile.trim())))
      {
        logger = Logger.getAnonymousLogger();
        fhdl = new FileHandler(logfile, true);
        fhdl.setFormatter(new SimpleFormatter());
        logger.addHandler(fhdl);
        logger.setLevel(Level.INFO);
        logger.info("***");
      }
      con = DriverManager.getConnection("jdbc:default:connection");
      con.setAutoCommit(false);
      if (logger != null) logger.info("Trying to prepare: " + sql);
      cst = con.prepareCall(sql);
      if (logger != null) logger.info("Prepared: " + sql);
      cst.execute();
      if (logger != null) logger.info("Executed: " + sql);
    } 
    catch (SQLException ex)
    {
      if (logger != null) 
      {
        while (ex != null) 
        {
          if (ex instanceof DB2Diagnosable) 
          {
            DB2Diagnosable db2ex = (DB2Diagnosable) ex;
            com.ibm.db2.jcc.DB2Sqlca sqlca = db2ex.getSqlca();
            if (sqlca != null) 
              logger.severe("\nSQLCODE: " + sqlca.getSqlCode() + "\nMESSAGE: " + sqlca.getMessage());
            else 
              logger.severe("\nError code: " + ex.getErrorCode() + "\nError msg : " + ex.getMessage());
          } 
          else 
            logger.severe("\nError code (no db2): " + ex.getErrorCode() + "\nError msg  (no db2): " + ex.getMessage());
          logger.log(Level.SEVERE, ex.getMessage(), ex);
          ex = ex.getNextException();
        }
      }
    } 
    finally
    {
      if (fhdl != null) {fhdl.close(); fhdl = null;}
      if (cst != null) {cst.close(); cst = null;}
      if (con != null) {con.close(); con = null;}
    }
  }

}

关于如何构建和部署它的说明：

# Suppose we are on a Db2 server and !!!db2profile is sourced in the session!!!
# java sources are in source
# java classes are in classes

$ ls -l
drwxr-xr-x classes
drwxr-xr-x source
drwxr-xr-x sql

$ find source -name '*.java'
source/ru/ibm/db2udf/ExecAny.java

# Compile
$ (cd source; ${DB2_HOME}/java/jdk64/bin/javac -d ../classes ru/ibm/db2udf/ExecAny.java)
# Create jar
$ ${DB2_HOME}/java/jdk64/bin/jar cvf exec_any.jar -C classes ru/ibm/db2udf/ExecAny.class

# Deploy jar
$ db2 connect to mydb
#$ db2 "call sqlj.replace_jar('file:${PWD}/exec_any.jar', 'EXEC_ANY')"
$ db2 "call sqlj.install_jar('file:${PWD}/exec_any.jar', 'EXEC_ANY')"
$ db2 "call sqlj.refresh_classes()"

# Jar file must appear in the ${DB2_HOME}/function/jar directory
$ find ${DB2_HOME}/function/jar -name '*.jar'
.../sqllib/function/jar/<USER_NAME>/EXEC_ANY.jar

# SP CREATE and CALL commands
$ cat sql/exec_any.sql
CREATE OR REPLACE PROCEDURE EXEC_ANY
(
  SQL VARCHAR(4000)
, LOG VARCHAR(512) DEFAULT NULL
)
LANGUAGE Java
EXTERNAL NAME 'EXEC_ANY:ru.ibm.db2udf.ExecAny.exec'
FENCED THREADSAFE
MODIFIES SQL DATA
PARAMETER STYLE JAVA;

(=
-- W/ logging to some file accessible by the db2 instance fenced user on the server
-- $ stat -c "%U" ${DB2_HOME}/ctrl/.fencedID
call exec_any('declare global temporary table test(i int) on commit preserve rows not logged', '/tmp/exec_any.txt');
call exec_any('insert into session.test values 1', '/tmp/exec_any.txt');
-- W/o logging
call exec_any('insert into session.test values 2');
select * from session.test;
=)