jdbc 初级

               jdbc 初级

import java.nio.channels.SelectableChannel;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import com.mysql.jdbc.Driver;public class TestLogin {    public static void main(String[] args) {    //登录的业务方法    public static void login(String username,String pwd) throws SQLException{        //[1]注册驱动         DriverManager.registerDriver(new Driver());        //[2]获取连接         Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/cz1", "root", "123");        //[3]准备要执行的sql语句        String sql = "select * from login where username = ? and password =?";        //[4]获取statement对象 执行sql语句//      Statement statement = connection.createStatement();        PreparedStatement statement = connection.prepareStatement(sql);        //[4.1]设置? 占位的内容 1代表第一个?        statement.setString(1, username);        statement.setString(2, pwd);        //[5]执行sql语句        ResultSet resultSet = statement.executeQuery();        //[6]如果根据我们写sql语句查询出结果 就证明登录成功         if (resultSet.next()) {            System.out.println("登录成功");        }else {            System.out.println("登录失败");        }        resultSet.close();        statement.close();        connection.close();    } }

import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import org.junit.Test;import com.mysql.jdbc.Driver;public class JdbcHelloWorld{    /**     *[1]不同的数据库厂商都提供了数据库的驱动 驱动以jar包的形式提供    [2]注册驱动    [3]连接你想操作的数据库    [4]准备你想要执行的sql语句   [5]执行你准备好的sql语句     * @throws SQLException      * @throws Exception      */    @Test    public void jdbcText(){        //[2]获取数据库的连接 :  mysql的意思是连接到mysql的数据库  cz1是连接的数据库的名字        Connection connection = null;        //[4]获取statement对象         Statement statement = null;        //[5]执行sql语句         ResultSet resultSet = null;        try {            //[1]注册驱动             DriverManager.registerDriver(new Driver());            connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/cz1", "root", "123");            //[3]准备你要执行的sql语句            String sql = "select * from orders";            statement = connection.createStatement();            resultSet = statement.executeQuery(sql);            while(resultSet.next()){                int id = resultSet.getInt("id");                String name = resultSet.getString("name");                System.out.println("id:"+id+"----"+name);            }            //释放的原则  先打开的后释放         } catch (Exception e) {            e.printStackTrace();        }    }    @Test    public void jdbcHelloAdd() throws Exception{        //[1]注册驱动         DriverManager.registerDriver(new Driver());        //[2]获取数据库的连接 :  mysql的意思是连接到mysql的数据库  cz1是连接的数据库的名字        Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/cc1", "root", "123");        //[3]准备你要执行的sql语句        String sql = "insert into orders values(8,'xiyiji','500')";        //[4]获取statement对象         Statement statement = connection.createStatement();        //[5]执行sql语句         int result = statement.executeUpdate(sql);        if (result!=0) {            System.out.println("插入成功");        }else {            System.out.println("插入失败");        }        //释放的原则  先打开的后释放         statement.close();        connection.close();    }}