javaweb中mysql数据库连接方法

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rootString 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 blocke.printStackTrace();}resultSet = null;}if (statement != null) {try {statement.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}statement = null;}if (connection != null) {try {connection.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.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#