oracle dbms_output 在java中输出

有没有碰到过这种情况，当你的java程序连接oracle运行存储过程的时候，java控制台只是仅仅输出java程序的相关信息，而存储过程中的dbms_output内容却没有办法显示？这样只能跑去sql developer 单独调试存储过程，而不能直接在eclipse进行集成测试，出了问题也不好定位。  



所以在此分享一个解决方案： [原文链接][1] 。05年的一个方法，不知现在有没有更好的：）  



* 存储过程demo

```pl/sql

create or replace

PROCEDURE test_java_dbmsOutPut

IS

BEGIN

   dbms_output.put_line('im in store procedure');

END;

/

```

* 用来输出dbms_output 的类

```java

import java.sql.*;

class DbmsOutput 

 {

    /*

     * our instance variables. It is always best to use callable or prepared

     * statements and prepare (parse) them once per program execution, rather

     * then one per execution in the program. The cost of reparsing is very

     * high. Also -- make sure to use BIND VARIABLES!

     * 

     * we use three statments in this class. One to enable dbms_output -

     * equivalent to SET SERVEROUTPUT on in SQL*PLUS. another to disable it --

     * like SET SERVEROUTPUT OFF. the last is to "dump" or display the results

     * from dbms_output using system.out

     */

    private CallableStatement enable_stmt;

    

    private CallableStatement disable_stmt;

    

    private CallableStatement show_stmt;

    

    /*

     * our constructor simply prepares the three statements we plan on

     * executing.

     * 

     * the statement we prepare for SHOW is a block of code to return a String

     * of dbms_output output. Normally, you might bind to a PLSQL table type but

     * the jdbc drivers don't support PLSQL table types -- hence we get the

     * output and concatenate it into a string. We will retrieve at least one

     * line of output -- so we may exceed your MAXBYTES parameter below. If you

     * set MAXBYTES to 10 and the first line is 100 bytes long, you will get the

     * 100 bytes. MAXBYTES will stop us from getting yet another line but it

     * will not chunk up a line.

     */

    public DbmsOutput(Connection conn)

        throws SQLException {

        enable_stmt = conn.prepareCall("begin dbms_output.enable(:1); end;");

        disable_stmt = conn.prepareCall("begin dbms_output.disable; end;");

        show_stmt =

            conn.prepareCall("declare "

                + "    l_line varchar2(255); "

                + "    l_done number; "

                + "    l_buffer long; "

                + "begin "

                + "  loop "

                + "    exit when length(l_buffer)+255 > :maxbytes OR l_done = 1; "

                + "    dbms_output.get_line( l_line, l_done ); "

                + "    l_buffer := l_buffer || l_line || chr(10); "

                + "  end loop; " + " :done := l_done; "

                + " :buffer := l_buffer; " + "end;");

    }

    

    /*

     * enable simply sets your size and executes the dbms_output.enable call

     */

    public void enable(int size)

        throws SQLException {

        enable_stmt.setInt(1, size);

        enable_stmt.executeUpdate();

    }

    

    /*

     * disable only has to execute the dbms_output.disable call

     */

    public void disable()

        throws SQLException {

        disable_stmt.executeUpdate();

    }

    

    /*

     * show does most of the work. It loops over all of the dbms_output data,

     * fetching it in this case 32,000 bytes at a time (give or take 255 bytes).

     * It will print this output on stdout by default (just reset what

     * System.out is to change or redirect this output).

     */

    public void show()

        throws SQLException {

        int done = 0;

        show_stmt.registerOutParameter(2, java.sql.Types.INTEGER);

        show_stmt.registerOutParameter(3, java.sql.Types.VARCHAR);

        for (;;) {

            show_stmt.setInt(1, 32000);

            show_stmt.executeUpdate();

            System.out.print(show_stmt.getString(3));

            if ((done = show_stmt.getInt(2)) == 1)

                break;

        }

    }

    

    /*

     * close closes the callable statements associated with the DbmsOutput

     * class. Call this if you allocate a DbmsOutput statement on the stack and

     * it is going to go out of scope -- just as you would with any callable

     * statement, result set and so on.

     */

    public void close()

        throws SQLException {

        enable_stmt.close();

        disable_stmt.close();

        show_stmt.close();

    }

}

```

* 测试代码

```java

import java.sql.*;



public class Test{

    public static void main(String args[])

        throws SQLException {

        DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());

        Connection conn = DBAgent.getConn(); 

        conn.setAutoCommit(false);

        Statement stmt = conn.createStatement();

        DbmsOutput dbmsOutput = new DbmsOutput(conn);

        dbmsOutput.enable(1000000);

        stmt.execute("begin test_java_dbmsOutPut; end;"); #调用存储过程

        stmt.close();

        dbmsOutput.show(); #显示DBMS_OUTPUT

        dbmsOutput.close();

        conn.close();

    }   

}

```



* 输出的结果  

运行测试代码之后，就可以看见在java 控制台输出了

```

im in store procedure

```

> 这样就可以让java为我们输出DBMS_OUTPUT，就像SQL*PLUS一样。你需要做的仅仅是在java运行存储过程之后，调用DbmsOutput.show() ，就能显示这个存储过程内的DBMS_OUTPUT，是不是很方便？再也不用在eclipse和sql develper之间两头调试了



  [1]: http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:45027262935845