• JDBC快速入门和获取数据库的连接方式

    本次博客带领大家快速入门JDBC和获取数据库的连接方式。

    JDBC程序编写步骤

    1. 注册驱动 - 加载Driver 类。
    2. 获取连接 - 得到Connection。
    3. 执行增删改查 - 发送SQL 给 mysql 执行。
    4. 释放资源 - 关闭相关连接。

    JDBC第一个程序

    • 通过jdbc 对 表actor 进行 添加，删除和修改操作。
    -- 先在mysql数据库中创建actor表
CREATE TABLE actor(
	id INT PRIMARY KEY AUTO_INCREMENT,
	NAME VARCHAR(32) NOT NULL DEFAULT '',
	sex CHAR(1) NOT NULL DEFAULT '女',
	borndate DATETIME,
	phone VARCHAR(12));

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    • 实现代码：
    public class Jdbc01 {
    public static void main(String[] args) throws SQLException {

        // 前置工作：在项目下创建一个文件夹比如 libs
        // 将mysql.jar 拷贝到该目录下面，点击add to project ..加入到该项目
        //1.注册驱动
        Driver driver = new Driver();
        //2.得到连接
        String url = "jdbc:mysql://localhost:3306/ld_db01";
        //将 用户名和密码放入到Properties对象
        Properties properties = new Properties();
        properties.setProperty("user","root");//用户
        properties.setProperty("password","root");//密码
        Connection connect = driver.connect(url, properties);

        //3.执行sql
        //String sql = "insert into actor values(null,'刘德华','男','1970-11-11','110')";
        //String sql = "update actor set name='周星驰' where id = 1";
        String sql = "DELETE from actor where id = 1";
        //Statement用于执行静态SQL语句并返回其生成的结果的对象
        Statement statement = connect.createStatement();
        int rows = statement.executeUpdate(sql); //如果是dml语句，返回的就是影响行数。

        System.out.println(rows > 0 ? "成功":"失败");

        //4.关闭连接资源
        statement.close();
        connect.close();
    }
}

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    获取数据库连接的5种方式

    • 方式1：
        public void connect01() throws SQLException {
        Driver driver = new Driver();
        //得到连接
        String url = "jdbc:mysql://localhost:3306/ld_db01";
        //将 用户名和密码放入到Properties对象
        Properties properties = new Properties();
        properties.setProperty("user","root");//用户
        properties.setProperty("password","root");//密码
        Connection connect = driver.connect(url, properties);
        System.out.println(connect);
    }

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    • 方式2：方式1会直接使用com.mysql.jdbc.Driver(),属于静态加载，灵活性差，依赖强。
    public void connect02() throws ClassNotFoundException, IllegalAccessException, InstantiationException, SQLException {
        //使用反射加载Driver类
        Class aClass = Class.forName("com.mysql.jdbc.Driver");
        Driver driver = (Driver)aClass.newInstance();
        String url = "jdbc:mysql://localhost:3306/ld_db01";
        //将 用户名和密码放入到Properties对象
        Properties properties = new Properties();
        properties.setProperty("user","root");//用户
        properties.setProperty("password","root");//密码
        Connection connect = driver.connect(url, properties);
        System.out.println(connect);
    }

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    • 方式3：使用DriverManager 替代 Diver 进行统一管理。
    public void connect03() throws ClassNotFoundException, IllegalAccessException, InstantiationException, SQLException {
        //使用反射加载Driver
        Class<?> aClass = Class.forName("com.mysql.jdbc.Driver");
        Driver driver = (Driver)aClass.newInstance();
        //创建url和user和password
        String url = "jdbc:mysql://localhost:3306/ld_db01";
        String user = "root";
        String password = "root";
        DriverManager.registerDriver(driver);
        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println(connection);
    }

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    • 方式4：使用Class.forName 自动完成注册驱动，简化代码。
    public void connect04() throws ClassNotFoundException, SQLException {
        //使用反射加载了 Driver类
        //在加载 Driver类时，完成注册
        Class.forName("com.mysql.jdbc.Driver");
        //创建url和user和password
        String url = "jdbc:mysql://localhost:3306/ld_db01";
        String user = "root";
        String password = "root";
        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println(connection);
    }

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    • 方式5：在方式4的基础上改进，增加配置文件，让连接mysql更加灵活。
    public void connect05() throws IOException, ClassNotFoundException, SQLException {
        //通过Properties对象获取配置文件的信息
        Properties properties = new Properties();
        properties.load(new FileInputStream("src\\mysql.properites"));
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        String driver = properties.getProperty("driver");
        String url = properties.getProperty("url");
        Class.forName(driver);
        Connection connection = DriverManager.getConnection(url, user, password);
        System.out.println(connection);
    }

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    user = root
password = root
url = jdbc:mysql://localhost:3306/ld_db01
driver = com.mysql.jdbc.Driver

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    小练习

    1. 创建news表。

    2. 使用jdbc添加5条数据。

    3. 修改id=1的记录，将content 改成 一个新的消息。

    4. 删除id = 3的记录。

    -- 1.
CREATE TABLE news (
	id INT PRIMARY KEY AUTO_INCREMENT,
	NAME VARCHAR(32) NOT NULL DEFAULT '',
	content TEXT NOT NULL 
)

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    // 2.
public class JdbcTest {
    public static void main(String[] args) throws IOException, ClassNotFoundException, SQLException {
        Properties properties = new Properties();
        properties.load(new FileInputStream("src\\mysql.properites"));
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        String driver = properties.getProperty("driver");
        String url = properties.getProperty("url");
        Class.forName(driver);
        Connection connection = DriverManager.getConnection(url, user, password);
        String sql1 = "insert into news values(1,'广州','广州疫情最新情况！')";
        String sql2 = "insert into news values(2,'北京','北京疫情最新情况！')";
        String sql3 = "insert into news values(3,'上海','上海疫情最新情况！')";
        String sql4 = "insert into news values(4,'重庆','重庆疫情最新情况！')";
        String sql5 = "insert into news values(5,'汕头','汕头疫情最新情况！')";
        Statement statement = connection.createStatement();
        int rows = statement.executeUpdate(sql1);
        rows = statement.executeUpdate(sql2);
        rows = statement.executeUpdate(sql3);
        rows = statement.executeUpdate(sql4);
        rows = statement.executeUpdate(sql5);

        statement.close();
        connection.close();

    }
}

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    // 3.
public class JdbcTest {
    public static void main(String[] args) throws IOException, ClassNotFoundException, SQLException {
        Properties properties = new Properties();
        properties.load(new FileInputStream("src\\mysql.properites"));
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        String driver = properties.getProperty("driver");
        String url = properties.getProperty("url");
        Class.forName(driver);
        Connection connection = DriverManager.getConnection(url, user, password);
        String sql = "update news set content='中秋快乐！！！' where id = 1";
        Statement statement = connection.createStatement();
        int rows = statement.executeUpdate(sql);

        statement.close();
        connection.close();
    }
}

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    //4.
public class JdbcTest {
    public static void main(String[] args) throws IOException, ClassNotFoundException, SQLException {
        Properties properties = new Properties();
        properties.load(new FileInputStream("src\\mysql.properites"));
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        String driver = properties.getProperty("driver");
        String url = properties.getProperty("url");
        Class.forName(driver);
        Connection connection = DriverManager.getConnection(url, user, password);
        String sql = "DELETE from news where id = 1";
        Statement statement = connection.createStatement();
        int rows = statement.executeUpdate(sql);

        statement.close();
        connection.close();
    }
}

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  • 原文地址：https://blog.csdn.net/lidong777777/article/details/126731410