import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class DBUtil { public static final String DRIVER = "com.mysql.jdbc.Driver"; public static final String URL = "jdbc:mysql://localhost:3306/db"; public static final String USERNAME = "root"; public static final String PASSWORD = "root"; /** * 通过静态代码块 注冊数据库驱动 */ static { try { Class.forName(DRIVER); } catch (ClassNotFoundException e) { e.printStackTrace(); } } /** * 获得Connection * * @return */ public static Connection getConnection() { Connection conn = null; try { conn = DriverManager.getConnection(URL, USERNAME, PASSWORD); } catch (SQLException e) { e.printStackTrace(); } return conn; } /** * 获得Statement * * @return */ public static Statement getStatement() { Statement st = null; try { st = getConnection().createStatement(); } catch (SQLException e) { e.printStackTrace(); } return st; } /** * 关闭ResultSet * * @param rs */ public static void closeResultSet(ResultSet rs) { if (rs != null) { try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } } } /** * 关闭Statement * * @param st */ public static void closeStatement(Statement st) { if (st != null) { try { st.close(); } catch (SQLException e) { e.printStackTrace(); } } } /** * 关闭Connection * * @param conn */ public static void closeConnection(Connection conn) { if (conn != null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } /** * 关闭所有 * * @param rs * @param sta * @param conn */ public static void closeAll(ResultSet rs, Statement sta, Connection conn) { closeResultSet(rs); closeStatement(sta); closeConnection(conn); } /** * 获得总记录数 * * @return */ public static int getRows() { int rows = 0; Statement sta = null; ResultSet rs = null; Connection conn = getConnection(); try { sta = conn.createStatement(); rs = sta.executeQuery("select * from e_user"); rs.last(); rows = rs.getRow(); } catch (SQLException e) { e.printStackTrace(); } return rows; } }
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