簡單工具類：

public class JDBCSimpleUtils {
    /**
     * 私有構造方法
     */
    private JDBCSimpleUtils() {
    }

    /**
     * 驅動
     */
    public static String driver = null;
    /**
     * 連接字符串
     */
    public static String url = null;
    /**
     * 用戶名
     */
    public static String user = null
 
;
    /**
     * 密碼
     */
    public static String password = null;

    /**
     * 讀取配置文件, 並將讀取到的值賦值給變量.
     */
    public static void readConfig() {
        try {
            //讀取properties配置文件給變量賦值
            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();
        }
    }

    /**
     * 靜態代碼塊
     * 變量賦值
     * 並註冊驅動
     
 
*/
    static {
        try {
            //變量賦值
            readConfig();
            //註冊驅動
            Class.forName(driver);
        } catch (Exception e) {
            //寫入日誌
            //Logger.WriteLog(JDBCUtils.class.getName(),"");
            e.printStackTrace();
        }
    }

    /**
     * 獲取Connection
     *
     * @return 數據庫連接
     */
    public static Connection getConnection() {

        try {
            return DriverManager.getConnection(url, user, password);
        } catch (SQLException ex) {
            //寫入日誌
            //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);
            // 設置數據集可以滾動,可以更新
        } catch (SQLException ex) {
            //寫入日誌
            //Logger.WriteLog(JDBCUtils.class.getName(),"");
            release(conn);
        }
        return null;
    }

    /**
     * 獲取一個帶參數的 PreparedStatement
     * 該 PreparedStatement 已經設置數據集 可以滾動,可以更新
     *
     * @param conn      數據庫連接
     * @param cmdText   需要 ? 參數的 SQL 語句
     * @param cmdParams SQL 語句的參數表
     * @return 如果獲取失敗將返回 null,調用時記得檢查返回值
     */
    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);
            //寫入日誌
            //Logger.WriteLog(JDBCUtils.class.getName(),"");
        }
        return pstmt;
    }


    /**
     * 釋放資源
     *
     * @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();
            //寫入日誌
            //Logger.WriteLog(JDBCUtils.class.getName(),"");
        } finally {
            try {
                if (stat != null) {
                    stat.close();
                    stat = null;
                }
            } catch (SQLException e) {
                e.printStackTrace();
                //寫入日誌
                //Logger.WriteLog(JDBCUtils.class.getName(),"");
            } finally {
                try {
                    if (conn != null) {
                        conn.close();
                        conn = null;
                    }
                } catch (SQLException e) {
                    e.printStackTrace();
                    //寫入日誌
                    //Logger.WriteLog(JDBCUtils.class.getName(),"");
                }
            }
        }
    }

    /**
     * 釋放資源
     *
     * @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();
            //寫入日誌
            //Logger.WriteLog(JDBCUtils.class.getName(),"");
        } finally {
            try {
                if (conn != null) {
                    conn.close();
                    conn = null;
                }
            } catch (SQLException e) {
                e.printStackTrace();
                //寫入日誌
                //Logger.WriteLog(JDBCUtils.class.getName(),"");
            }
        }
    }

    /**
     * 釋放資源
     *
     * @param conn Connection
     */
    public static void release(Connection conn) {
        try {
            if (conn != null) {
                conn.close();
                conn = null;
            }
        } catch (SQLException e) {
            e.printStackTrace();
            //寫入日誌
            //Logger.WriteLog(JDBCUtils.class.getName(),"");
        }
    }
}

簡單工具類的應用：

public class DemoTest {
    public static void main(String[] args) {
        String sql1 = "SELECT * FROM users";
        getResultSet(sql1);

        Object[] objs = new Object[2];
        objs[0] = "123456789";
        objs[1] = 2;
        String sql2 = "UPDATE users SET psw= ? WHERE uid= ?";
        executeNoQuery(sql2, objs);
    }

    /**
     * 增刪改的方法
     *
     * @param sql
     * @param obj
     */
    private static void executeNoQuery(String sql, Object... obj) {
        //獲取Connection
        Connection conn = JDBCSimpleUtils.getConnection();
        //獲取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();
        }
    }


    /**
     * 查詢返回ResultSet
     *
     * @param sql
     */
    private static void getResultSet(String sql) {
        //獲取Connection
        Connection conn = JDBCSimpleUtils.getConnection();
        //獲取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);
        }
    }
}

java基礎之JDBC三：簡單工具類的提取及應用