JDBC连接jar包工具

1）准备

a》jdbc驱动包

2）原理：

编写jdbc数据库连接，命令行传递参数，最后打成jar包

3）实施

public static void main(String[] args) {

		// 输入参数判断
		// 1）DB_URL
		// 2）Username
		// 3）Password  4）Sql-执行Sql
		if (args == null || args.length < 4) {
			System.out.println("传递的参数不足4个【url,Username,Password,Sql(含空格用双引号引起)】,参数之间用空格分开。");
			return;
		}

		// 获取参数
		String url = args[0];
		String user = args[1];
		String password = args[2];
		String sql = args[3];

		// 设置驱动名称
		String driverName = "oracle.jdbc.driver.OracleDriver";
		if (url.contains("jdbc:mysql")) {
			driverName = "com.mysql.jdbc.Driver";
		}

		// 加载驱动,建立连接
		Connection con = null;
		Statement statement = null;
		ResultSet resultSet = null;
		try {
			Class.forName(driverName);
			con = DriverManager.getConnection(url, user, password);
			System.out.println("db连接成功.");
			statement = con.createStatement();
			resultSet = statement.executeQuery(sql);
			ResultSetMetaData resultMetaData = resultSet.getMetaData();

			// 获取所有列名
			int cols = resultMetaData.getColumnCount();
			String resultRow = "";
			for (int i = 1; i <= cols; i++) {
				resultRow += resultMetaData.getColumnName(i) + "    ";
			}
			System.out.println("数据结果：");
			System.out.println(resultRow);
			
			// 获取所有值
			while (resultSet.next()) {
				resultRow = "";
				for (int i = 1; i <= cols; i++) {
					try {
						resultRow += resultSet.getString(i) + "    ";
					} catch (NullPointerException e) {
						e.printStackTrace();
					}
				}
				System.out.println(resultRow); 
			}

		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			try {
				resultSet.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}finally{
				try {
					statement.close();
					con.close();
					System.out.println("db连接关闭成功.");
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
			
		}

	}