Re: [OT] a Collection of beans to store sql data
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Bob,
Bob Hall wrote:
You missed the essence of Chris's suggestion:
3. Throw an exception in your catch(SQLException) block.
In other words, your catch block would swallow the SQLException
should one occur.
Just to be clear, I usually don't advocate the swallowing of an
exception. I typically encourage the use of a wrapped exception, like this:
catch (SQLException sqle)
{
throw new ApplicationSpecficException(Cannot query db, sqle);
}
Where the original exception is kept around, and even shows up in the
stack trace as the root cause.
- -chris
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Re: [OT] a Collection of beans to store sql data
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Michael,
Michael Ni wrote:
My problem is i get
PersonNew.java:48: missing return statement
}
[snip]
public Collection getPersondata( String alias, String password ) {
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
Collection retValue = new ArrayList();
String query = SELECT * FROM person WHERE alias = ?, password = ?;
try {
conn = DBConnection.getDBConnection();
stmt = conn.prepareStatement( query );
stmt.setString( 1, alias );
stmt.setString( 2, password );
rs = stmt.executeQuery();
while (rs.next()) {
PersonalInfo beanrow = new PersonalInfo();
beanrow.setAlias(rs.getString(alias));
beanrow.setPassword(rs.getString(password));
retValue.add(beanrow);
}
return retValue;
}
catch( SQLException sqle ) {
sqle.printStackTrace();
}
finally {
try {if (rs != null) rs.close();} catch (SQLException e) {}
try {if (stmt != null) stmt.close();} catch (SQLException e) {}
try {if (conn != null) conn.close();} catch (SQLException e) {}
}
}
The problem is that you have a code path that can exit your method
without returning a value (which is a no-no). If a SQLException is
thrown inside your try block, it will be caught, logged, and then the
method exists with no return value.
You have several options:
1. Put a catch-all return at the very end of the method
(after the finally block)
2. Put a return in your catch(SQLException) block.
3. Throw an exception in your catch(SQLException) block.
I tend to favor #3 since a SQLException usually indicates a real problem
rather than something that is recoverable, but this may not be true
under your particular circumstances.
- -chris
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Re: [OT] a Collection of beans to store sql data
thanks for the quick reply, by the way everyone is telling me to make my
functions return objects instead of resultset. why is returning resultset
bad?
From: Christopher Schultz [EMAIL PROTECTED]
Reply-To: Tomcat Users List users@tomcat.apache.org
To: Tomcat Users List users@tomcat.apache.org
Subject: Re: [OT] a Collection of beans to store sql data
Date: Wed, 10 Jan 2007 21:15:50 -0500
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Michael,
Michael Ni wrote:
My problem is i get
PersonNew.java:48: missing return statement
}
[snip]
public Collection getPersondata( String alias, String password ) {
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
Collection retValue = new ArrayList();
String query = SELECT * FROM person WHERE alias = ?, password = ?;
try {
conn = DBConnection.getDBConnection();
stmt = conn.prepareStatement( query );
stmt.setString( 1, alias );
stmt.setString( 2, password );
rs = stmt.executeQuery();
while (rs.next()) {
PersonalInfo beanrow = new PersonalInfo();
beanrow.setAlias(rs.getString(alias));
beanrow.setPassword(rs.getString(password));
retValue.add(beanrow);
}
return retValue;
}
catch( SQLException sqle ) {
sqle.printStackTrace();
}
finally {
try {if (rs != null) rs.close();} catch (SQLException e) {}
try {if (stmt != null) stmt.close();} catch (SQLException e) {}
try {if (conn != null) conn.close();} catch (SQLException e) {}
}
}
The problem is that you have a code path that can exit your method
without returning a value (which is a no-no). If a SQLException is
thrown inside your try block, it will be caught, logged, and then the
method exists with no return value.
You have several options:
1. Put a catch-all return at the very end of the method
(after the finally block)
2. Put a return in your catch(SQLException) block.
3. Throw an exception in your catch(SQLException) block.
I tend to favor #3 since a SQLException usually indicates a real problem
rather than something that is recoverable, but this may not be true
under your particular circumstances.
- -chris
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Re: [OT] a Collection of beans to store sql data
On 1/10/07, Michael Ni [EMAIL PROTECTED] wrote:
thanks for the quick reply, by the way everyone is telling me to make my
functions return objects instead of resultset. why is returning resultset
bad?
Because of this line:
try {if (rs != null) rs.close();} catch (SQLException e) {}
Your function is closing the result set. If you return a closed ResultSet,
what good is it?
You must close the connection when you're finished with it (so that
connection pooling will work). Before you close the connection, you must
close the ResultSet. Before you close the ResultSet, you must get the data
out of it.
--
Len
Re: [OT] a Collection of beans to store sql data
hmmm there is a sqlexception in my catch block, unless i'm doing it wrong.
mike
From: Christopher Schultz [EMAIL PROTECTED]
Reply-To: Tomcat Users List users@tomcat.apache.org
To: Tomcat Users List users@tomcat.apache.org
Subject: Re: [OT] a Collection of beans to store sql data
Date: Wed, 10 Jan 2007 21:15:50 -0500
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Hash: SHA1
Michael,
Michael Ni wrote:
My problem is i get
PersonNew.java:48: missing return statement
}
[snip]
public Collection getPersondata( String alias, String password ) {
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
Collection retValue = new ArrayList();
String query = SELECT * FROM person WHERE alias = ?, password = ?;
try {
conn = DBConnection.getDBConnection();
stmt = conn.prepareStatement( query );
stmt.setString( 1, alias );
stmt.setString( 2, password );
rs = stmt.executeQuery();
while (rs.next()) {
PersonalInfo beanrow = new PersonalInfo();
beanrow.setAlias(rs.getString(alias));
beanrow.setPassword(rs.getString(password));
retValue.add(beanrow);
}
return retValue;
}
catch( SQLException sqle ) {
sqle.printStackTrace();
}
finally {
try {if (rs != null) rs.close();} catch (SQLException e) {}
try {if (stmt != null) stmt.close();} catch (SQLException e) {}
try {if (conn != null) conn.close();} catch (SQLException e) {}
}
}
The problem is that you have a code path that can exit your method
without returning a value (which is a no-no). If a SQLException is
thrown inside your try block, it will be caught, logged, and then the
method exists with no return value.
You have several options:
1. Put a catch-all return at the very end of the method
(after the finally block)
2. Put a return in your catch(SQLException) block.
3. Throw an exception in your catch(SQLException) block.
I tend to favor #3 since a SQLException usually indicates a real problem
rather than something that is recoverable, but this may not be true
under your particular circumstances.
- -chris
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