简单工具类：
public class JDBCSimpleUtils { /** * 私有构造方法 */ private JDBCSimpleUtils() { } /** * 驱动 */ public static String driver = null; /** * 连接字符串 */ public static String url = null; /** * 用户名 */ public static String user = null; /** * 密码 */ public static String password = null; /** * 读取配置文件, 并将读取到的值赋值给变量. */ public static void readConfig() { try { //读取properties配置文件给变量赋值 Properties pp = new Properties(); pp.load(new FileReader("day04_classTest\\src\\config.properties")); url = pp.getProperty("url"); user = pp.getProperty("username"); driver = pp.getProperty("driver"); password = pp.getProperty("password"); } catch (Exception e) { e.printStackTrace(); } } /** * 静态代码块 * 变量赋值 * 并注册驱动 */ static { try { //变量赋值 readConfig(); //注册驱动 Class.forName(driver); } catch (Exception e) { //写入日志 //Logger.WriteLog(JDBCUtils.class.getName(),""); e.printStackTrace(); } } /** * 获取Connection * * @return 数据库连接 */ public static Connection getConnection() { try { return DriverManager.getConnection(url, user, password); } catch (SQLException ex) { //写入日志 //Logger.WriteLog(JDBCUtils.class.getName(),""); ex.printStackTrace(); return null; } } public static Statement getStatement(Connection conn) { if (conn == null) { return null; } try { return conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE); // 设置数据集可以滚动,可以更新 } catch (SQLException ex) { //写入日志 //Logger.WriteLog(JDBCUtils.class.getName(),""); release(conn); } return null; } /** * 获取一个带参数的 PreparedStatement * 该 PreparedStatement 已经设置数据集 可以滚动,可以更新 * * @param conn 数据库连接 * @param cmdText 需要 ? 参数的 SQL 语句 * @param cmdParams SQL 语句的参数表 * @return 如果获取失败将返回 null,调用时记得检查返回值 */ public static PreparedStatement getPreparedStatement(Connection conn, String cmdText, Object... cmdParams) { if (conn == null) { return null; } PreparedStatement pstmt = null; try { pstmt = conn.prepareStatement(cmdText, ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE); int i = 1; for (Object item : cmdParams) { pstmt.setObject(i, item); i++; } } catch (SQLException e) { e.printStackTrace(); release(conn, pstmt); //写入日志 //Logger.WriteLog(JDBCUtils.class.getName(),""); } return pstmt; } /** * 释放资源 * * @param conn Connection * @param stat Statement * @param rs ResultSet */ public static void release(Connection conn, Statement stat, ResultSet rs) { try { if (rs != null) { rs.close(); rs = null; } } catch (SQLException e) { e.printStackTrace(); //写入日志 //Logger.WriteLog(JDBCUtils.class.getName(),""); } finally { try { if (stat != null) { stat.close(); stat = null; } } catch (SQLException e) { e.printStackTrace(); //写入日志 //Logger.WriteLog(JDBCUtils.class.getName(),""); } finally { try { if (conn != null) { conn.close(); conn = null; } } catch (SQLException e) { e.printStackTrace(); //写入日志 //Logger.WriteLog(JDBCUtils.class.getName(),""); } } } } /** * 释放资源 * * @param conn Connection * @param stat Statement */ public static void release(Connection conn, Statement stat) { try { if (stat != null) { stat.close(); stat = null; } } catch (SQLException e) { e.printStackTrace(); //写入日志 //Logger.WriteLog(JDBCUtils.class.getName(),""); } finally { try { if (conn != null) { conn.close(); conn = null; } } catch (SQLException e) { e.printStackTrace(); //写入日志 //Logger.WriteLog(JDBCUtils.class.getName(),""); } } } /** * 释放资源 * * @param conn Connection */ public static void release(Connection conn) { try { if (conn != null) { conn.close(); conn = null; } } catch (SQLException e) { e.printStackTrace(); //写入日志 //Logger.WriteLog(JDBCUtils.class.getName(),""); } }}
简单工具类的应用：
/** * 增删改的方法 * * @param sql * @param obj */ private static void executeNoQuery(String sql, Object... obj) { //获取Connection Connection conn = JDBCSimpleUtils.getConnection(); //获取PreparedStatement PreparedStatement ps = JDBCSimpleUtils.getPreparedStatement(conn, sql, obj); try { int i = ps.executeUpdate(); if (i > 0) { System.out.println("ok"); } else { System.out.println("error"); } } catch (SQLException e) { e.printStackTrace(); } finally { JDBCSimpleUtils.release(conn, ps); } } /** * 查询返回ResultSet * * @param sql */ private static void getResultSet(String sql) { //获取Connection Connection conn = JDBCSimpleUtils.getConnection(); //获取Statement Statement stat = JDBCSimpleUtils.getStatement(conn); ResultSet rs = null; try { rs = stat.executeQuery(sql); while (rs.next()) { int id = rs.getInt("uid"); String name = rs.getString("uname"); String psw = rs.getString("psw"); System.out.println(id + "--" + name + "--" + psw); } } catch (SQLException e) { e.printStackTrace(); } finally { JDBCSimpleUtils.release(conn, stat, rs); } }