渚漪Day22——JavaWeb 12【JDBC】

JDBC

编写JDBC固定步骤

1、加载驱动

<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.47</version>
    </dependency>
</dependencies>

2、连接数据库

String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncording=utf-8&useSSL=false";
String username="root";
String password="123456";
Connection connection = DriverManager.getConnection(url, username, password);

3、向数据库发送SQL对象Statement

Statement statement=connection.createStatement();

4、编写sql代码

String sql = "select * from users;";

5、执行sql（得到结果进行处理）

ResultSet resultSet = statement.executeQuery(sql);
while(resultSet.next()){
    System.out.println("id："+resultSet.getInt("id"));
    System.out.println("名字："+resultSet.getString("name"));
    System.out.println("密码："+resultSet.getString("password"));
    System.out.println("邮箱："+resultSet.getString("email"));
    System.out.println("生日："+resultSet.getString("birthday"));
    System.out.println("===============================");
}

6、关闭连接，释放资源

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

代码

Statement代码

import java.sql.*;

public class test {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncording=utf-8&useSSL=false";
        String username="root";
        String password="123456";


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


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

        Statement statement=connection.createStatement();


        String sql = "select * from users;";
        ResultSet resultSet = statement.executeQuery(sql);
        while(resultSet.next()){
            System.out.println("id："+resultSet.getInt("id"));
            System.out.println("名字："+resultSet.getString("name"));
            System.out.println("密码："+resultSet.getString("password"));
            System.out.println("邮箱："+resultSet.getString("email"));
            System.out.println("生日："+resultSet.getString("birthday"));
            System.out.println("===============================");
        }
        resultSet.close();
        statement.close();
        connection.close();

    }
}

PreparedStatement 代码

import java.sql.*;

public class test2 {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncoding=utf-8&useSSL=false";
        String username="root";
        String password="123456";


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


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

        String sql = "insert into jdbc.users(id, name, password, email, birthday) VALUE (?,?,?,?,?)";


        PreparedStatement preparedStatement = connection.prepareStatement(sql);

        preparedStatement.setInt(1, 4);
        preparedStatement.setString(2, "鹿乃");
        preparedStatement.setString(3, "kano");
        preparedStatement.setString(4, "kano@qq.com");
        preparedStatement.setString(5, "1995-12-24");

        int i=preparedStatement.executeUpdate();

        if(i>0){
            System.out.println("插入成功");
        }
        preparedStatement.close();
        connection.close();

    }
}