什么时JDBC?
答:JDBC全称时Java Data Base Connectivity,是执行sql语句的Java Api。
使用JDBC的步骤:
- 导入数据库驱动包
- 注册驱动
- 获取数据库连接
- 获取执行Sql语句的对象
- 执行Sql
- 关闭连接
public void JDBC() {
try {
//注册驱动
Class.forName("com.mysql.cj.jdbc.Driver");
//获取数据库连接
Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC", "root", "12345678");
//获取执行Sql语句的对象
Statement statement = connection.createStatement();
//执行Sql
ResultSet resultSet = statement.executeQuery("select * from user ");
//遍历结果集
while (resultSet.next()) {
System.out.println(resultSet.getString(1));
System.out.println(resultSet.getString(2));
System.out.println(resultSet.getString(3));
}
} catch (SQLException | ClassNotFoundException e) {
e.printStackTrace();
} finally {
/*
关闭资源时,先使用的后关闭
关闭前判断是否为null
*/
try {
if (resultSet != null)
resultSet.close();
if (statement != null)
statement.close();
if (connection != null)
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}