JDBC

题目1：编写一个应用程序，输入用户名和密码，访问test数据库中t_login表（字段包括id、username、password），验证登录是否成功。

题目2：在上一题基础上，当登录成功后，将t_user表（id、name、sex、birthday）的信息进行显示（要求使用DB.java完成登录和获取t_user表中数据的操作），最后再对t_user表进行一条记录的添加操作。

package Test;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import xiaofei.StudentEntity.Login;
import xiaofei.StudentEntity.User;


public class JDBCTest {
    private static final String URL = "jdbc:mysql://localhost:3306/test";
    private static final String USERNAME = "root";
    private static final String PASSWORD = "xiaofei";
    //根据学号查询学生
        public Login queryStudentBySno(int id) {
            Connection connection = null;
            PreparedStatement pstat = null;
            ResultSet rs = null;
            Login login = null;
            try {
                Class.forName("com.mysql.jdbc.Driver");
                connection = DriverManager.getConnection(URL, USERNAME, PASSWORD);
                String sql = "select * from t_login where id = ?";
                pstat = connection.prepareStatement(sql);
                pstat.setInt(1, id);
                rs = pstat.executeQuery();
                if(rs.next()) {
                    String username = rs.getString("username");
                    int id1 = rs.getInt("id");
                    String password = rs.getString("password");
                    login = new Login(id1,username,password);
                }
                return login;
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
                return null;
            }catch(SQLException e) {
                e.printStackTrace();
                return null;
            }catch(Exception e) {
                e.printStackTrace();
                return null;
            }finally {
                try {
                    if(rs!=null)rs.close();
                    if(connection!=null)connection.close();
                    if(pstat!=null)pstat.close();
                }catch(SQLException e) {
                    e.printStackTrace();
                }catch(Exception e) {
                    e.printStackTrace();
                }
            }
        }
        //查询所有的用户
        public List<User> queryAllUsers(){
            List<User> users = new ArrayList<User>();
            Connection connection = null;
            PreparedStatement pstat = null;
            ResultSet rs = null;
            User user = null;
            try {
                Class.forName("com.mysql.jdbc.Driver");
                connection = DriverManager.getConnection(URL, USERNAME, PASSWORD);
                String sql = "select * from t_user";
                pstat = connection.prepareStatement(sql);
                rs = pstat.executeQuery();
                while(rs.next()) {
                    int id = rs.getInt("id");
                    String name = rs.getString("name");
                    String sex = rs.getString("sex");
                    String birthday = rs.getString("birthday");
                    user = new User(id,name,sex,birthday);
                    users.add(user);
                }
                return users;
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
                return null;
            }catch(SQLException e) {
                e.printStackTrace();
                return null;
            }catch(Exception e) {
                e.printStackTrace();
                return null;
            }finally {
                try {
                    if(rs!=null)rs.close();
                    if(connection!=null)connection.close();
                    if(pstat!=null)pstat.close();
                }catch(SQLException e) {
                    e.printStackTrace();
                }catch(Exception e) {
                    e.printStackTrace();
                }
            }
        }
        //添加用户
        public boolean addUser(User user) {
            Connection connection = null;
            PreparedStatement pstat = null;
            try {
                Class.forName("com.mysql.jdbc.Driver");
                connection = DriverManager.getConnection(URL, USERNAME, PASSWORD);
                String sql = "insert into t_user values(?,?,?,?)";
                pstat = connection.prepareStatement(sql);
                pstat.setInt(1, user.getId());
                pstat.setString(2, user.getName());
                pstat.setString(3, user.getSex());
                pstat.setString(4, user.getBirthday());
                int count = pstat.executeUpdate();
                if(count>0)
                    return true;
                else
                    return false;
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
                return false;
            }catch(SQLException e) {
                e.printStackTrace();
                return false;
            }catch(Exception e) {
                e.printStackTrace();
                return false;
            }finally {
                try {
                    if(connection!=null)connection.close();
                    if(pstat!=null)pstat.close();
                }catch(SQLException e) {
                    e.printStackTrace();
                }catch(Exception e) {
                    e.printStackTrace();
                }
            }
        }
}

package xiaofei.StudentEntity;

public class Login {
    private int id;
    private String username;
    private String passwrod;
    public Login() {}
    public Login(int id, String username, String passwrod) {
        this.id = id;
        this.username = username;
        this.passwrod = passwrod;
    }
    public Login( String username, String passwrod) {
        this.username = username;
        this.passwrod = passwrod;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPasswrod() {
        return passwrod;
    }
    public void setPasswrod(String passwrod) {
        this.passwrod = passwrod;
    }
}

package xiaofei.StudentEntity;

public class User {
    private int id;
    private String name;
    private String sex;
    private String birthday;
    public User(int id, String name, String sex, String birthday) {
        super();
        this.id = id;
        this.name = name;
        this.sex = sex;
        this.birthday = birthday;
    }
    public User() {}
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public String getBirthday() {
        return birthday;
    }
    public void setBirthday(String birthday) {
        this.birthday = birthday;
    }
    
}

进行登录的验证代码

package Test;

import java.util.Scanner;

import xiaofei.StudentEntity.Login;

public class Test19 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner scanner = new Scanner(System.in); 
        System.out.println("请输入您的id");
        int id = scanner.nextInt();
        System.out.println("请输入您的姓名");
        String username = scanner.next();
        System.out.println("请输入您的密码");
        String password = scanner.next();
        JDBCTest jdbc = new JDBCTest();
        Login login = jdbc.queryStudentBySno(id);
        if(login!=null) {
            if(id==login.getId()&&username.equals(login.getUsername())&&password.equals(login.getPasswrod())) {
                System.out.println("用户登录成功！！！");
            }else {
                System.out.println("用户登录失败！！！");
            }
        }else {
            System.out.println("用户登录失败！！！");
        }
    }

}

进行展示表中全部数据的代码

package Test;

import java.util.ArrayList;
import java.util.List;
import xiaofei.StudentEntity.User;

public class Test20 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println("显示全部信息！！！");
        JDBCTest jdbc = new JDBCTest();
        List<User> users = new ArrayList<User>();
        users = jdbc.queryAllUsers();
        for(User user : users) {
            System.out.println(user.getId()+"  "+user.getName()+"  "+user.getSex()+"  "+user.getBirthday());
        }
    }

}

进行添加用户的代码

package Test;

import java.util.Scanner;

import xiaofei.StudentEntity.User;

public class Tset21 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入您要添加用户的id");
        int id = scanner.nextInt();
        System.out.println("请输入您要添加用户的姓名");
        String name = scanner.next();
        System.out.println("请输入您要添加用户的性别");
        String sex = scanner.next();
        System.out.println("请输入您要添加用户的生日");
        String birthday = scanner.next();
        User user = new User(id,name,sex,birthday);
        JDBCTest jdbc = new JDBCTest();
        boolean flag = jdbc.addUser(user);
        if(flag) {
            System.out.println("用户添加成功！！！");
        }else {
            System.out.println("用户添加失败！！！");
        }
    }

}

验证登录成功显示的图片

显示表中全部信息的图片

添加新的用户