数据库

一、数据库

1.1 数据库种类

1.2 框架&工具

二、数据库在Java中的使用原理

利用多态的特性，Java提供一个接口（规范sql语句），而MySQL、SqlServer等实现该接口（将实现类打包成一个jar包）

三、JDBC的使用

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import com.mysql.cj.jdbc.Driver;

public class Demo {
	static {
		try {
			//注册驱动
			new Driver();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	public static void main(String[] args) {
		Connection connection = null;
		Statement statement = null;
		ResultSet resultSet = null;
		try {
			//建立连接数据库
			String url = "jdbc:mysql://localhost:3306/student?serverTimezone=UTC";
			String username = "root";
			String password = "123456";
			connection = DriverManager.getConnection(url, username, password);
			//创建执行语句平台
			String sql = "SELECT * FROM student";
			statement = connection.createStatement();
			//执行sql操作
			resultSet = statement.executeQuery(sql);
			//获得数据
			while (resultSet.next()) {
				int id = resultSet.getInt("id");
				String name = resultSet.getString("name");
				int age = resultSet.getInt("age");
				System.out.println(id + "..." + name + "..." + age);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally {
			//关闭资源
			try {
				if(connection != null) {
					connection.close();
				}
				if(statement != null) {
					statement.close();
				}
				if(resultSet != null) {
					resultSet.close();
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		
	}
}

pom.xml中（MySQL可以去找search.maven.org）

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>cn.kooun.db</groupId>
  <artifactId>database</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  
  <properties>
  	<maven.compiler.source>1.8</maven.compiler.source>
  	<maven.compiler.target>1.8</maven.compiler.target>
  </properties>
  
  <dependencies>
  	<dependency>
  		<groupId>mysql</groupId>
  		<artifactId>mysql-connector-java</artifactId>
  		<version>8.0.18</version>
  	</dependency>
  </dependencies>
</project>