JDBC

JDBC

JDBC ：Java 连接数据库的缩写

需要jar包支持:

• java.sql
• javax.sql
• mysql-conneter-java…（连接驱动）

导入数据库依赖

<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>8.0.22</version>
</dependency>

IDEA连接数据库

public class TestJdbc {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        String url="jdbc:mysql://localhost:3306/shop?useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8";
        String username="root";
        String password="123456";
        //1.加载驱动
        Class.forName("com.mysql.cj.jdbc.Driver");
        //2.连接数据库
        Connection connection = DriverManager.getConnection(url, username, password);
        //3.编写SQL
        String sql="insert into person (id, name, address) values (?,?,?);";
        //4.预编译
        PreparedStatement preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setInt(1,3);//给第一个占位符赋值
        preparedStatement.setString(2,"张山");//给第二个占位符赋值
        preparedStatement.setString(3,"US");//给第三个占位符赋值
        //5.执行SQL
        int i = preparedStatement.executeUpdate();
        if(i>0){
            System.out.println("成功");
        }
        preparedStatement.close();
        connection.close();
    }
}

JDBC固定步骤

1.加载驱动

Class.forName("com.mysql.cj.jdbc.Driver");

2.连接数据库驱动

Connection connection = DriverManager.getConnection(url, username, password);

3.创建与数据库交互的对象

Statement statement = connection.createStatement();

4.编写SQL

String sql="select * from `users`";

5.执行并应用

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("password="+resultSet.getObject("password")); 

6.关闭

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