JDBC 关闭数据库连接与自动提交

               // Jdbc关闭数据库连接时,会隐含一个提交事务的操作

        
        private final static String DB_DRIVER = "oracle.jdbc.driver.OracleDriver";
	private final static String DB_CONNECTION = "jdbc:oracle:thin:@127.0.0.1:1521:mydb01";
	private final static String DB_NAME = "scott";
	private final static String DB_PWd = "scott";

	
	//jdbc关闭自动提交. 在对数据库的操作未提交时,当conn.close()时,会默认先提交事务,再关闭连接.
	public static void test1() {
		Connection conn = null;
		CallableStatement callStmt = null;
		PreparedStatement ps = null;
		try {
			Class.forName(DB_DRIVER);
			conn = DriverManager.getConnection(DB_CONNECTION, DB_NAME, DB_PWd);
			conn.setAutoCommit(false); //关闭自动提交
			ps = conn.prepareStatement("insert into t_user values (?, ?, ?)");
			ps.setString(1, "1");
			ps.setString(2, "1");
			ps.setString(3, "1");
			int results = ps.executeUpdate();
			//conn.commit();//不手动提交
			System.out.println("插入了" + results + "条: ");

		} catch (Exception e) {
			try {
				conn.rollback();
			} catch (SQLException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
			e.printStackTrace(System.out);
		} finally {
			try {
				conn.setAutoCommit(true);
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			if (null != callStmt) {
				try {
					callStmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (null != conn) {
				try {
					conn.close();// jdbc关闭自动提交. 在jdbc未提交时,当conn.close()时,会默认先提交事务,再关闭连接.
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}
	
	
	//jdbc默认自动提交. 在对数据库的操作未手动提交时,也会立即提交到数据库并生效
	public static void test2() {
		Connection conn = null;
		CallableStatement callStmt = null;
		PreparedStatement ps = null;
		try {
			Class.forName(DB_DRIVER);
			conn = DriverManager.getConnection(DB_CONNECTION, DB_NAME, DB_PWd);
			// conn.setAutoCommit(false); //jdbc默认自动提交
			ps = conn.prepareStatement("insert into t_user values (?, ?, ?)");
			ps.setString(1, "1");
			ps.setString(2, "1");
			ps.setString(3, "1");
			int results = ps.executeUpdate();  //注意,这一步操作就被提交到数据库了!!!
			//conn.commit();//不手动提交
			System.out.println("插入了" + results + "条: ");

		} catch (Exception e) {
			try {
				conn.rollback();
			} catch (SQLException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
			e.printStackTrace(System.out);
		} finally {
			try {
				conn.setAutoCommit(true);
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			if (null != callStmt) {
				try {
					callStmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (null != conn) {
				try {
					conn.close();//  jdbc关闭连接
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}