JDBC复习

JDBC复习

什么是JDBC

Java database Connection：Java数据库连接

图解

需要的jar包

1 java.sql

2 javax.sql

3 mysql-connector-java:连接驱动

新建一个数据库

CREATE TABLE `users` (
  `id` int(11) NOT NULL,
  `name` varchar(50) DEFAULT NULL,
  `password` varchar(40) DEFAULT NULL,
  `email` varchar(50) DEFAULT NULL,
  `birthday` date DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO users (id,name,password,email,birthday)VALUES(1,'张三','123456','cakin@qq.com','2020-01-01');
​

 

导入数据库依赖

<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.46</version>
    </dependency>
</dependencies>
​

 

IDEA连接数据源

JDBC固定步骤

1 加载驱动

2 连接数据库

3 向数据库发送SQL的对象Statement：CRUD

4 编写SQL

5 执行SQL

6 关闭连接

实战1

package com.cakin;
 
 
import java.sql.*;
 
 
/**
* @ClassName: JdbcTest
* @Description: Jdbc测试
* @Date: 2020/6/18
* @Author: cakin
*/
public class JdbcTest {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        // useUnicode=true&characterEncoding=utf8 解决中文乱码
        String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncoding=utf8";
        String username = "root";
        String password = "123456";
 
 
        // 1 加载驱动
        Class.forName("com.mysql.jdbc.Driver");
        // 2 获得连接对象
        Connection connection = DriverManager.getConnection(url, username, password);
        // 3 获得发送SQL对象statement，可以进行增删查改操作
        Statement statement = connection.createStatement();
        // 4 编写SQL
        String sql = "select * from users";
        // 5 执行SQL
        ResultSet rs = statement.executeQuery(sql);
 
 
        while (rs.next()) {
            System.out.println("id=" + rs.getObject("id"));
            System.out.println("name=" + rs.getObject("name"));
            System.out.println("password=" + rs.getObject("password"));
            System.out.println("email=" + rs.getObject("email"));
        }
        // 6 关闭资源
        rs.close();
        statement.close();
        connection.close();
    }
}
​

 

实战2

package com.cakin;
 
 
import java.sql.*;
 
 
/**
* @ClassName: JdbcTest2
* @Description: jdbc测试
* @Date: 2020/6/18
* @Author: cakin
*/
public class JdbcTest2 {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        // useUnicode=true&characterEncoding=utf8 解决中文乱码
        String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncoding=utf8";
        String username = "root";
        String password = "123456";
 
 
        // 1 加载驱动
        Class.forName("com.mysql.jdbc.Driver");
        // 2 获得连接对象
        Connection connection = DriverManager.getConnection(url, username, password);
        // 3 编写SQL
        String sql = "insert into users(`id`, `name`, `password`, `email`, `birthday`) values (?,?,?,?,?)";
        // 4 预编译
        PreparedStatement preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setInt(1, 8);
        preparedStatement.setString(2, "cakin");
        preparedStatement.setString(3, "123456");
        preparedStatement.setString(4, "cakin@qq.com");
        preparedStatement.setDate(5, new Date(new java.util.Date().getTime()));
        // 5 执行
        preparedStatement.executeUpdate();
 
 
        // 6 关闭资源
        connection.close();
    }
}
​