import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class DBBean {

	private Connection con = null;
	private Statement stmt;
	private ResultSet rs;

	public DBBean() {
	}

	// 得到连接
	public Connection getConnextion() throws Exception {
		// 连接数据库的url
		String url = "jdbc:oracle:thin:@10.2.104.50:1521:orcl";
		// 用户名
		String dbuser = "scott";
		// 口令
		String dbpass = "a123456";

		if (con == null) {

			// 加载驱动程序，参数是驱动程序的名字
			Class.forName("oracle.jdbc.driver.OracleDriver");

			// 建立连接，第一个参数是url
			// 第二个参数是用户名，第三个参数是口令
			con = DriverManager.getConnection(url, dbuser, dbpass);
		}
		return con;
	}

	// 执行有结果集返回的sql语句
	public ResultSet executeQuery(String sql) throws Exception {
		con = getConnextion();
		if (con == null)
			throw new Exception("没有连接对象可用");
		// 创建语句对象
		stmt = con.createStatement();
		rs = stmt.executeQuery(sql);
		return rs;
	}

	// 执行更新语句
	public int executeUpdate(String sql) throws Exception {
		con = getConnextion();
		if (con == null)
			throw new Exception("没有连接可用");
		// 创建语句对象
		stmt = con.createStatement();
		// 执行sql语句
		return stmt.executeUpdate(sql);
	}

	public void close() {
		try {
			if (rs != null)
				rs.close();
		} catch (Exception e) {
		}
		try {
			stmt.close();
		} catch (Exception e) {
		}
		try {
			con.close();
		} catch (Exception e) {
		}
	}

	public static void main(String[] args) throws Exception {
		String sql = "select * from users";
		ResultSet rs = new DBBean().executeQuery(sql);
		while (rs.next()) {
			System.out.println(rs.getString(1));
		}
	}

}