JDBC

JDBC

下载一个数据库驱动jar包，mysql-connector-java ---> 项目新建一个lib目录 ---> 驱动jar包导入到lib目录 ---> 右键jar包选Add as library

连MySQL数据库的demo：

public class JDBCDemo{
    public static void main(String[] args) throws ClassNotFoundException,SQLException{
        //1.加载驱动
        Class.forName("com.mysql.jdbc.Driver");	//固定写法，加载驱动
        //2.用户信息和url
        String url = "jdbc:mysql://localhost:3306/jdbcstudy?			  useUnicode=true&characterEncoding=utf8&useSSL=true";
        String username = "root";
        String password = "123456";
        //3.连接成功，数据库对象 Connection 代表数据库
        Connection connection = DriverManager.getConnection(url,username,password);
        //4.执行SQL对象Statement执行SQL的对象
        Statement statement = connection.createStatement();
        //5.执行SQL的对象去执行SQL，可能存在结果，查看返回结果
        String sql = "SELECT * FROM users";
        ResultSet resultSet = statement.executeQuery(sql);
        while(resultSet.next()){
            System.out.println("id="resultSet.getObject("id"));
             System.out.println("name="resultSet.getObject("NAME"));
             System.out.println("pwd="resultSet.getObject("PASSWORD"));
             System.out.println("email="resultSet.getObject("email"));
             System.out.println("birth="resultSet.getObject("birthday"));
             System.out.println("================================");
        }
        //6.释放连接
        resultSet.close();
        statement.close();
        connection.close();
    }
}

步骤总结：

1. 加载驱动
2. 连接数据库DriverManager
3. 获得执行SQL的对象Statement
4. 获得返回的结果集
5. 释放连接