杂记数据库

1、数据库连接

public class DBHelper {    /**     * 数据库驱动     */    public static final String DRIVER_NAME = "com.mysql.jdbc.Driver"; // MySQL数据库    //public static final String DRIVER_NAME = "oracle.jdbc.driver.OracleDriver"; // Oracle数据库    //public static final String DriverName = "com.microsoft.jdbc.sqlserver.SQLServerDriver"; // SQL Server数据库    /**     * JDBC URL     */    public static final String URL = "jdbc:mysql://localhost:3306/databasename?characterEncoding=gbk"; // MySQL数据库    //public static final String URL = "jdbc:oracle:thin:@localhost:1521:databasename?characterEncoding=gbk"; // Oracle数据库    //public static final String URL = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=databasename?characterEncoding=gbk"; // SQL Server数据库    // 用户名    public static final String USER_NAME = "";    // 密码    public static final String PASS = "";    private Connection conn;    public PreparedStatement statement;    public DBHelper(String sql) {        try {            // 加载数据驱动            Class.forName(DRIVER_NAME);            // 创建数据连接            conn = DriverManager.getConnection(URL, USER_NAME, PASS);            // 预编译加载sql(增删改查)            statement = conn.prepareStatement(sql);        } catch (ClassNotFoundException e) {            e.printStackTrace();        } catch (SQLException e) {            e.printStackTrace();        }    }    public void close() {        if (statement != null) {            try {                conn.close();            } catch (SQLException e) {                e.printStackTrace();            }        }    }}