[1]JDBC简单介绍和示例
import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public final class JdbcUtilsSing {private String url = "jdbc:mysql://localhost:3306/jdbc";private String user = "root";private String password = "";// private static JdbcUtilsSing instance = new JdbcUtilsSing();private static JdbcUtilsSing instance = null;private JdbcUtilsSing() {}public static JdbcUtilsSing getInstance() {if (instance == null) {synchronized (JdbcUtilsSing.class) {if (instance == null) {instance = new JdbcUtilsSing();}}}return instance;}static {try {Class.forName("com.mysql.jdbc.Driver");} catch (ClassNotFoundException e) {throw new ExceptionInInitializerError(e);}}public Connection getConnection() throws SQLException {return DriverManager.getConnection(url, user, password);}public void free(ResultSet rs, Statement st, Connection conn) {try {if (rs != null)rs.close();} catch (SQLException e) {e.printStackTrace();} finally {try {if (st != null)st.close();} catch (SQLException e) {e.printStackTrace();} finally {if (conn != null)try {conn.close();} catch (SQLException e) {e.printStackTrace();}}}}}

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