Re: some problem with CLOB
relogout@gmail.com, 10.09.2008 04:35:
I have a oracle table with a CLOB field named NEWS_CONTETN, and I want
put some news information which may be larger than 4k, I have searched
for some example and take following steps:
1. insert an empty clob to the table
sql1="insert into TAB1(id,COL_CLOB) values(1,empty_clob())";
2. initialize a CLOB variable and select the clob field for update
sql2="select COL_CLOB from TAB1 where id=1 for update";
oracle.sql.CLOB clob=null;
if(rs.next()){
clob=(oracle.sql.CLOB)rs.getClob("COL_CLOB");
}
3. put the news information to the CLOB variable
===================
HERE IS MY PROBLEM
in step 3, i have tried 3 ways, but it didn't work :(
===================
(1) clob.putChars(1,newsStr.toString().toCharArray()); //newsStr is
a string
(2) java.io.OutputStream out = clob.setAsciiStream(0);
(3) Writer outStream = clob.getCharacterOutputStream();
4. update the table
sql3="update TAB1 set COL_CLOB=? where id='1'";
I can't use any method of oracle.sql.CLOB, and get an exception null
what should i do? pls anyone help me, thanks in advance!
First of all: make sure you use an Oracle 10.x driver. The Oracle 9.x drivers do not support LOBs in a decent fashion.
1) Insert (or update) a CLOB
String sql = "insert into tab1 (col_clob) values (?)";
String myLongClobContent = " ... whatever ...";
StringReader r = new StringReader(myLongClobContent);
PreparedStatement stmt = connection.prepareStatement(sql);
stmt.setCharacterStream(1, r, myLongClobContent.length());
stmt.executeUpdate();
connection.commit();
2) to read a CLOB
String sql = "SELECT col_clob FROM tyb1";
Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery(sql);
while (rs.next())
{
Reader in = rs.getCharacterStream(1);
// read from the stream into a String variable
// or simply use getString(1), I think that is supported by newer drivers as well.
}
Again: make sure your driver version is at least 10.1
Thomas