JDBC

 

步骤

 

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

public class hs {
    public static void main(String[] args) throws Exception {
        //注册驱动
        Class.forName("com.mysql.jdbc.Driver");

        //注册连接
        String url="jdbc:mysql://127.0.0.1:3306/student";
        String username="root";
        String password="a1b2c3";
        Connection conn= DriverManager.getConnection(url,username,password);

        //定义sql
        String sql="UPDATE student SET NAME='bear' WHERE id='312';";

        //获取执行sql语句的对象
        Statement stmt=conn.createStatement();

        //得到执行成功行数并执行sql
        int count=stmt.executeUpdate(sql);

        System.out.println(count);

       //关闭资源
        stmt.close();
        conn.close();

    }
}

 

 

 

API:

DriverManager:

 

 

Connection:

 

 

 

 

数据库连接池：

 

 

 

 

 

 

导入jar包

 

配置文件内容：

driverClassName=com.mysql.jdbc.Driver

url=jdbc:mysql://localhost:3306/student?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC
characterEncoding=utf-8

username=root
password=a1b2c3

initialSize=5

maxActive=10

maxWait=3000

validationQuery=SELECT 1

testWhileIdle=true




使用druid连接池：

public class druids {
    public static void main(String[] args) throws Exception {
        //导入druid jar包
        //定义配置文件
        //加载配置文件
        Properties prop=new Properties();

        prop.load(new FileInputStream("C:\\Users\\Administrator\\IdeaProjects\\JDBC\\JDB\\src\\druid1.properties"));
        //获取连接池对象
        DataSource datasource= DruidDataSourceFactory.createDataSource(prop);
        //获取数据库连接
        Connection connection=datasource.getConnection();

        System.out.println(connection);
       // System.out.println(System.getProperty("user.dir"));
    }
}