8.12 Excepción de inicio de sesión y operación de archivo

1. Excepción de inicio de sesión

import sun.rmi.transport.Connection;

import javax.security.auth.login.LoginException;
import java.io.RandomAccessFile;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Scanner;

public class Denglu {
    public Denglu(String message) {
    }

    public static void  main(String[] args)throws LoginException{
        Connection connection=null;
        PreparedStatement statement=null;
        Scanner input=new Scanner(System.in);
        //1.加载驱动
        try {
            Class.forName("com.mysql.jdbc.Driver");
        }catch (ClassNotFoundException e){
            e.printStackTrace();
        }
        //2.创建连接
        try {
            connection = (Connection) DriverManager.getConnection
                    ("jdbc:mysql://127.0.0.1:3306/nbcj?useSSL=true&characterEncoding=utf-8&user=root&password=123456");
            String sql = "select * from student where username=? and password=? ";
            System.out.println("请输入用户名");
            String name=input.next();
            System.out.println("请输入密码：");
            String password=input.next();
            //4.得到statement对象
            statement = connection.prepareStatement(sql);
            statement.setString(1, "123");
            statement.setString(2, "123");
            ResultSet resultSet = statement.executeQuery();
            if (resultSet.next()){
                System.out.println("登入成功");
            }else {
                throw new LoginException("用户名密码不对");
            }

        }catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                resultSet.close();
            }catch (SQLException e){
                e.printStackTrace();
            }
        }
        if (statement!=null){
            try {
                statement.close();
            }catch (SQLException e){
                e.printStackTrace();
            }
        }
        if (connection!=null){
            try {
                connection.close();
            }catch (SQLException e){
                e.printStackTrace();
            }
        }
        System.out.println("111111");
        //5.执行sql得到结果集
        //6.处理结果集
        //7.关闭资源
    } catch (SQLException e) {
            e.printStackTrace();
        }
    }

2. operación de archivo

import com.sun.java.util.jar.pack.Package;

        import java.io.File;
        import java.io.IOException;

public class Testfile {
    public static void main(String[] args)throws IOException {
        File file=new File("D:\\PPT模板\\aaa.txt");
        file.createNewFile();
        File file1=new File("D:\\PPT模板\\bbb.txt");
        file.renameTo(file1);

        System.out.println(file);
    }
}