一、直接连接，不封装到工具类中，主要步骤：
先导包:MySQL-connector-java-5.0.8-bin.jar(点击跳转到下载界面),放在WebRoot/WEB-INF/lib/下
1.加载驱动//com.MySQL.jdbc.Driver 2.获取连接 Connection对象 3.获取用于向数据库发送SQL的Statement对象 4.执行sql,获取数据，解析数据 5.关闭连接，释放资源
/* 协议：子协议://主机:端口/数据库名 */ String url = "jdbc:mysql://localhost:3306/jdbctest"; // mysql数据库的用户名与密码，安装时自己设置，一般默认为root String user = "root"; String passWord = "root"; Connection connection = null; Statement statement = null; ResultSet resultSet = null; try { // 1.加载驱动//com.mysql.jdbc.Driver /* * DriverManager.registerDriver(new * Driver());用这种方法会加载两次驱动，也就是说会创建两个drive对象 */ Class.forName("com.mysql.jdbc.Driver"); // 2.获取连接 connection = DriverManager.getConnection(url, user, password); // 3.获取用于向数据库发送SQL的Statement对象 statement = connection.createStatement(); // 4.执行sql,获取数据 resultSet = statement.executeQuery("SELECT * FROM users;"); // 解析数据 while (resultSet.next()) { int id = resultSet.getInt("id"); String name = resultSet.getString("name"); String PSD = resultSet.getString("password"); String email = resultSet.getString("email"); String birthday = resultSet.getString("birthday"); System.out.PRintln(id + " " + name + " " + psd + " " + email + " " + birthday); } } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { //5.关闭连接，释放资源 if (resultSet != null) { try { resultSet.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } resultSet = null; } if (statement != null) { try { statement.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } statement = null; } if (connection != null) { try { connection.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } connection = null; } 
/* 协议：子协议://主机:端口/数据库名 */ String url = "jdbc:mysql://localhost:3306/jdbctest"; // mysql数据库的用户名与密码，安装时自己设置，一般默认为root String user = "root"; String password = "root"; Connection connection = null; Statement statement = null; ResultSet resultSet = null; try { // 1.加载驱动//com.mysql.jdbc.Driver /* * DriverManager.registerDriver(new * Driver());用这种方法会加载两次驱动，也就是说会创建两个drive对象 */ Class.forName("com.mysql.jdbc.Driver"); // 2.获取连接 connection = DriverManager.getConnection(url, user, password); // 3.获取用于向数据库发送SQL的Statement对象 statement = connection.createStatement(); // 4.执行sql,获取数据 resultSet = statement.executeQuery("SELECT * FROM users;"); // 解析数据 while (resultSet.next()) { int id = resultSet.getInt("id"); String name = resultSet.getString("name"); String psd = resultSet.getString("password"); String email = resultSet.getString("email"); String birthday = resultSet.getString("birthday"); System.out.println(id + " " + name + " " + psd + " " + email + " " + birthday); } } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { //5.关闭连接，释放资源 if (resultSet != null) { try { resultSet.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } resultSet = null; } if (statement != null) { try { statement.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } statement = null; } if (connection != null) { try { connection.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } connection = null; } }二、将数据库连接封装成一个工具类
这样做的好处是，在实际开发中，就能做到，改一处即可修改全局。
1.建一个名为db.properties的配置文件，放于src/
[html] view plain copy url=jdbc:mysql://localhost:3306/jdbctest username=root password=root driver=com.mysql.jdbc.Driver 2.工具类：
import java.io.IOException; 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 JdbcUtil { //私有静态变量，用以读取配置文件 private static Properties config=new Properties(); static{ try { //配置资源文件 config.load(JdbcUtil.class.getClassLoader().getResourceAsStream("db.properties")); //加载驱动 Class.forName(config.getProperty("driver")); } catch (IOException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } } public static Connection getConnection(){ Connection connection=null; try { connection=DriverManager.getConnection(config.getProperty("url"),config.getProperty("username"),config.getProperty("password")); } catch (SQLException e) { e.printStackTrace(); } return connection; } //用以关闭连接，释放资源 public static void releaseConn(Connection connection, Statement statement, ResultSet resultSet) { if(resultSet!=null){ try { resultSet.close(); } catch (SQLException e) { e.printStackTrace(); } resultSet=null; } if(statement!=null){ try { statement.close(); } catch (SQLException e) { e.printStackTrace(); } statement=null; } if(connection!=null){ try { connection.close(); } catch (SQLException e) { e.printStackTrace(); } connection=null; } } } 3.使用实例：
Connection connection = null; Statement statement = null; ResultSet resultSet = null; try { // 调用工具类中的静态方法来获取连接 connection = JdbcUtil.getConnection(); statement = connection.createStatement(); resultSet = statement.executeQuery("select * from users"); while (resultSet.next()) { int id = resultSet.getInt("id"); String name = resultSet.getString("name"); String psd = resultSet.getString("password"); String email = resultSet.getString("email"); String birthday = resultSet.getString("birthday"); System.out.println(id + " " + name + " " + psd + " " + email + " " + birthday); } } catch (Exception e) { e.printStackTrace(); } finally { // 调用工具类中的静态方法来关闭连接，释放资源 JdbcUtil.releaseConn(connection, statement, resultSet); } 来源：http://blog.csdn.net/beauxie/article/details/52748051#
