Java执行SQL代码块，得到dbms_output.put_line的结果

在Java中执行一段SQL的代码段如下：

declare var_user_no varchar2(50); begin select userName into var_user_no from user where user_id='1234'; dbms_output.put_line(var_user_no); end;

的时候因为不是存储过程所以没有什么入参和出参

 

我参考的是http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:45027262935845

帖子的内容，这里贴一下用作留存

 

Teaching other environments about DBMS_OUTPUT By default, tools such as SQL*PLUS and SVRMGRL are DBMS_OUTPUT aware. Most other environments are not. For example, your Java/JDBC program is definitely not DBMS_OUTPUT aware. We'll see in this section how to make Java/JDBC DBMS_OUTPUT aware. The same principles used below apply equally to any programming environment. The methods I use with Java can be easily applied to Pro*C, OCI, VB or any number of programmatic environments. We'll start with a small PL/SQL routine that generates some output data: scott@TKYTE816> create or replace 2 procedure emp_report 3 as 4 begin 5 dbms_output.put_line 6 ( rpad( 'Empno', 7 ) || 7 rpad('Ename',12) || 8 rpad('Job',11) ); 9 10 dbms_output.put_line 11 ( rpad( '-', 5, '-' ) || 12 rpad(' -',12,'-') || 13 rpad(' -',11,'-') ); 14 15 for x in ( select * from emp ) 16 loop 17 dbms_output.put_line 18 ( to_char( x.empno, '9999' ) || ' ' || 19 rpad( x.ename, 12 ) || 20 rpad( x.job, 11 ) ); 21 end loop; 22 end; 23 / Procedure created. scott@TKYTE816> set serveroutput on format wrapped scott@TKYTE816> exec emp_report Empno Ename Job ----- ---------- --------- 7369 SMITH CLERK 7499 ALLEN SALESMAN 7934 MILLER CLERK PL/SQL procedure successfully completed. Now, we'll set up a class to allow Java/JDBC to easily perform DBMS_OUTPUT for us. 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(); } } In order to demonstrate its use, I've set up the following small Java/JDBC test program. Here dbserver is the name of the database server and ora8i is the service name of the instance: import java.sql.*; class test { public static void main (String args []) throws SQLException { DriverManager.registerDriver (new oracle.jdbc.driver.OracleDriver()); Connection conn = DriverManager.getConnection ("jdbc:oracle:thin:@dbserver:1521:ora8i", "scott", "tiger"); conn.setAutoCommit (false); Statement stmt = conn.createStatement(); DbmsOutput dbmsOutput = new DbmsOutput( conn ); dbmsOutput.enable( 1000000 ); stmt.execute ( "begin emp_report; end;" ); stmt.close(); dbmsOutput.show(); dbmsOutput.close(); conn.close(); } } Now we will test it, by first compiling it and then running it: $ javac test.java $ java test Empno Ename Job ----- ---------- --------- 7369 SMITH CLERK 7499 ALLEN SALESMAN 7521 WARD SALESMAN So, that shows how to teach Java to do DBMS_OUTPUT for us. Just as SQL*PLUS does, you'll have to call DbmsOutput.show() after executing any statement that might procedure some output to be displayed. After we execute an insert, update, delete or stored procedure call SQL*PLUS is calling DBMS_OUTPUT.GET_LINES to get the output. Your Java (or C, or VB) application would call 'show' to display the results.

 

而实际时用的时候只需要将 main方法中的

 

stmt.execute ( "begin emp_report; end;" );

里面的SQL替换成你需要执行的SQL即可

 

 

而实际输出的时候是按照一句dbms_output.put_line一行输出来输出的。