Posts Tagged ‘database’
Checking Oracle availability with Spring jdbc 2.0
Spring Jdbc uses its own Runtime Exception hierarchy in order to provide Exceptions from the database layer. Hence, no Exception is thrown by database methods encapsuling queries and error control can be delegate to services.
Catching DataAccessResourceFailureException and CannotGetJdbcConnectionException should be enough to detect that database is down. However in Spring exceptions hierarchy exists UncategorizedDataAccessException too. Several Oracle critical errors are translated by Spring under this category.
By default, only error codes appearing in org.springframework.jdbc.support.sql-error-codes.xml are mapped to Spring customized exceptions. In order to detect another error codes SQLErrorCodeSQLExceptionTranslator class is provided. Every database exception its translated by this mechanism. The point is to include here the complete oracle error code list for database unavailability.
JdbcTemplate initialization
JdbcTemplate jt = new JdbcTemplate(dataSource); CustomExceptionTranslator cet = new CustomExceptionTranslator(); fet.setDataSource(dataSource); jt.setExceptionTranslator(fet);
Custom SQLErrorCodeSQLExceptionTranslator
import java.sql.SQLException;
import java.util.Arrays;
import java.util.List;
import org.springframework.dao.DataAccessException;
import org.springframework.dao.DataAccessResourceFailureException;
import org.springframework.jdbc.CannotGetJdbcConnectionException;
import org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator;
public class CustomExceptionTranslator extends SQLErrorCodeSQLExceptionTranslator {
// Oracle error codes uncategorized by Spring
private static final List<integer> ORACLE_CLOSED_ERROR_CODES =
Arrays.asList(1012, 1033, 1034, 1041, 1089, 1090, 1114,
12154, 12203, 12224, 12500, 12505, 12519, 12520,
12535, 12541, 12545, 12571, 1688, 17002, 17008,
17410, 17447, 23001, 27091, 27092, 27101, 3113, 3114);
/**
* Translate SQLExceptions to Spring RuntimeExceptions
*/
public DataAccessException translate(String task, String sql, SQLException sqlex) {
DataAccessException dae = super.translate(task, sql, sqlex);
if (dae instanceof DataAccessResourceFailureException ||
dae instanceof CannotGetJdbcConnectionException ||
ORACLE_CLOSED_ERROR_CODES.contains(sqlex.getErrorCode())) {
// Database is DOWN!
}
return dae;
}
}
Further information
