Java学习笔记-JDBC 1
Registering the Driver ClassThere are 3 ways to register a driver to your java program.
1 A JAR file can be automatically register if it contains a file name META-INF/services/java.sql.Driver
2 Load the driver class in your java program. For example:
Class.forName("oracle.jdbc.OracleDriver");
3 Set jdbc.driver property. You can specify the property with a command-line argument, such as
java -Djdbc.drivers=org.postgresql.Driver ProgramName Or your application can set the system property with a call such as
System.setProperty("jdbc.drivers", "org.postgresql.Driver");
Connecting to the Database
In your Java program, you open a database connection with code that is similar to the following example:
String url = "jdbc:postgresql:COREJAVA";String username = "dbuser";String password = "secret";Connection conn = DriverManager.getConnection(url, username, password);
Following code is a whole example.
import java.io.IOException;import java.io.InputStream;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.Properties;public class DBTest { public static void main(String[] args) { try { runTest(); } catch (SQLException ex) { for (Throwable t : ex) { t.printStackTrace(); } } catch (IOException ex) { ex.printStackTrace(); } } public static void runTest() throws IOException, SQLException { Connection conn = getConnection(); try { Statement stat = conn.createStatement(); stat.executeUpdate("CREATE TABLE Greetings (Message CHAR(20))"); stat.execute("INSERT INTO Greetings VALUES ('Hello, World!')"); ResultSet result = stat.executeQuery("SELECT * FROM Greetings"); if (result.next()) { System.out.println(result.getString(1)); } result.close(); stat.executeUpdate("DROP TABLE Greetings"); } finally { conn.close(); } } public static Connection getConnection() throws IOException, SQLException { Properties props = new Properties(); InputStream in = DBTest.class.getResourceAsStream("database.properties"); props.load(in); String drivers = props.getProperty("jdbc.drivers"); if (drivers != null) { System.setProperty("jdbc.drivers", drivers); } else { return null; } String url = props.getProperty("jdbc.url"); String username = props.getProperty("jdbc.username"); String password = props.getProperty("jdbc.password"); return DriverManager.getConnection(url, username, password); }}
database.properties file
jdbc.drivers=com.mysql.jdbc.Driverjdbc.url=jdbc:mysql:///javacorejdbc.username=rootjdbc.password=mysql
页:
[1]