Connection management
Database connections are expensive resources that must be closed properly to avoid memory leaks. Java's try-with-resources syntax automatically closes connections, statements, and result sets when the block completes, even if errors occur.
Ensure CityBook Libraries' application manages resources safely.
Diese Übung ist Teil des Kurses
Querying a PostgreSQL Database in Java
Anleitung zur Übung
- Wrap resources in a try-with-resources block.
- Add exception handling for database errors.
Interaktive Übung
Vervollständige den Beispielcode, um diese Übung erfolgreich abzuschließen.
public class Main {
public static void main(String[] args) {
// Use try-with-resources for automatic cleanup
____ (Connection conn = DriverManager.getConnection(Credentials.URL, Credentials.USER, Credentials.PASSWORD);
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM books")) {
while (rs.next()) {
System.out.println(rs.getString("title"));
System.out.println(rs.getInt("publication_year"));
}
// Handle database exceptions
} ____ (SQLException e) {
System.out.println("Error: " + e.getMessage());
System.out.println("SQLState: " + e.getSQLState());
}
}
}