JDBC连接数据库两种方式

package test;import java.nio.file.*;import java.sql.*;import java.io.*;import java.util.*;/** * This program tests that the database and the JDBC driver are correctly configured. * @version 1.02 2012-06-05 * @author Cay Horstmann */public class TestDB{   public static void main(String args[]) throws IOException   {      try      {         runTest();      }      catch (SQLException ex)      {         for (Throwable t : ex)            t.printStackTrace();      }   }   /**    * Runs a test by creating a table, adding a value, showing the table contents, and removing the    * table.    */   public static void runTest() throws SQLException, IOException   {      try {          Connection conn = getConnection();         Statement stat = conn.createStatement();         stat.executeUpdate("CREATE TABLE Greeting (Message CHAR(20))");         stat.executeUpdate("INSERT INTO Greeting VALUES ('Hello, World!')");         try (ResultSet result = stat.executeQuery("SELECT * FROM Greeting"))         {            if (result.next())               System.out.println(result.getString(1));         }//               }catch (ClassNotFoundException e) {        e.printStackTrace();    }   }   /**    * Gets a connection from the properties specified in the file database.properties.    * @return the database connection * @throws ClassNotFoundException     */   public static Connection getConnection() throws SQLException, IOException, ClassNotFoundException   {      Properties props = new Properties();      try (InputStream in = Files.newInputStream(Paths.get("resources/database.properties")))      {         props.load(in);      }      String drivers = props.getProperty("jdbc.drivers");      //第二种方式比较常见，用Class.forName()注册驱动      Class.forName(drivers);      //下面是第一种方式通过System.setProperty()注册驱动//      if (drivers != null) System.setProperty("jdbc.drivers", drivers);      String url = props.getProperty("jdbc.url");      String username = props.getProperty("jdbc.username");      String password = props.getProperty("jdbc.password");      return DriverManager.getConnection(url, username, password);   }}

• .properties配置文件

jdbc.drivers=com.mysql.jdbc.Driverjdbc.url=jdbc:mysql://localhost:3306/test?characterEncoding=utf8&useSSL=truejdbc.username=rootjdbc.password=admin