javafx实现登录注册界面

package sample;

import JavaBigJob.BaseScene;
import javafx.scene.Parent;
import javafx.scene.layout.Pane;
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.image.ImageView;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

import java.sql.ResultSet;
import java.sql.SQLException;

public class LoginFrame extends Application{
    Label nameLabel = new Label("User Name :");
    Label passwordLabel = new Label("Password  : ");

    HBox user = new HBox();
    HBox password = new HBox();
    TextField tfUser = new TextField();
    PasswordField tfPassword = new PasswordField();
    Button btLogIn = new Button("Log in");
    Button btSignIn = new Button("Sign in");
    HBox h3 = new HBox();//装按钮
    VBox pane = new VBox();

    @Override
    public void start(Stage stage) {
        user.getChildren().addAll(nameLabel,tfUser);
        user.setAlignment(Pos.CENTER);
        user.setSpacing(20);

        password.getChildren().addAll(passwordLabel,tfPassword);
        password.setAlignment(Pos.CENTER);
        password.setSpacing(20);

        h3.setAlignment(Pos.CENTER);
        btLogIn.setAlignment(Pos.BASELINE_RIGHT);
        btSignIn.setAlignment(Pos.BASELINE_RIGHT);
        h3.getChildren().addAll(btLogIn,btSignIn);
        h3.setSpacing(20);

        pane.setAlignment(Pos.CENTER);
        pane.setSpacing(20);
        pane.getChildren().addAll(user,password,h3);

        stage.setScene(new Scene(pane,400,250));
        stage.setTitle("Welcome!");
        stage.show();

        btLogIn.setOnAction(e->{
            if(user_exist()==false){
                System.out.println("用户不存在");
                HBox hBox = new HBox();
                Label label = new Label("用户不存在");
                ImageView image = new ImageView("No.png");
                image.setFitWidth(150);
                image.setFitHeight(120);
                hBox.setAlignment(Pos.CENTER);
                hBox.setSpacing(10);
                hBox.getChildren().addAll(image,label);
                Stage stage1 = new Stage();
                stage1.setScene(new Scene(hBox,300,200));
                stage1.setTitle("ERROR");
                stage1.show();
            }
            else if(user_right() & detection_information()){
                stage.hide();
                //登陆成功
                new Table01();
            }
        });

        btSignIn.setOnAction(e->{
            if(user_exist()){
                System.out.println("用户已存在");
                HBox hBox = new HBox();
                Label label = new Label("用户已存在");
                ImageView image = new ImageView("No.png");
                image.setFitWidth(150);
                image.setFitHeight(120);
                hBox.setAlignment(Pos.CENTER);
                hBox.setSpacing(10);
                hBox.getChildren().addAll(image,label);
                Stage stage1 = new Stage();
                stage1.setScene(new Scene(hBox,300,200));
                stage1.setTitle("ERROR");
                stage1.show();
            }
            else if(detection_information())
            {
                DataBaseUtil db = new DataBaseUtil();
                String sql = "INSERT INTO t_users (userName,password) VALUES (?,?)";
                db.updateExecute(sql,new String[]{tfUser.getText(),tfPassword.getText()});
                HBox hBox = new HBox();
                Label label = new Label("注册成功！");
                ImageView image = new ImageView("yes.png");
                image.setFitWidth(150);
                image.setFitHeight(120);
                hBox.setAlignment(Pos.CENTER);
                hBox.setSpacing(10);
                hBox.getChildren().addAll(image,label);
                Stage stage1 = new Stage();
                stage1.setScene(new Scene(hBox,300,200));
                stage1.show();
            }
        });
    }
    public Boolean user_exist(){//判断是否已存在用户
        DataBaseUtil db = new DataBaseUtil();
        String sql = "select count(*) from t_users where username = '"+tfUser.getText()+"'";
        try {
            ResultSet rs = db.queryExecute(sql);
            rs.next();
            if(rs.getInt(1)==1){
                return true;
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return false;
    }
    public Boolean user_right(){
        DataBaseUtil db = new DataBaseUtil();
        String sql = "select count(*) from t_users where username = ? and password = ?";
        try {
            ResultSet rs = db.queryExecute(sql,new String[]{tfUser.getText(),tfPassword.getText()});
            rs.next();
            if(rs.getInt(1)==1){
                return true;
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        System.out.println("用户名或密码不正确");
        HBox hBox = new HBox();
        Label label = new Label("用户名或密码不正确");
        ImageView image = new ImageView("No.png");
        image.setFitWidth(150);
        image.setFitHeight(120);
        hBox.setAlignment(Pos.CENTER);
        hBox.setSpacing(10);
        hBox.getChildren().addAll(image,label);
        Stage stage1 = new Stage();
        stage1.setScene(new Scene(hBox,300,200));
        stage1.setTitle("ERROR");
        stage1.show();
        return false;
    }

    public Boolean detection_information(){//判断信息是否填写完全

        if (tfUser.getText().equals("")||tfPassword.getText().equals("")){
            System.out.println("信息不全！");
            HBox hBox = new HBox();
            Label label = new Label("用户信息填写不全！");
            ImageView image = new ImageView("No.png");
            image.setFitWidth(150);
            image.setFitHeight(120);
            hBox.setAlignment(Pos.CENTER);
            hBox.setSpacing(10);
            hBox.getChildren().addAll(image,label);
            Stage stage1 = new Stage();
            stage1.setScene(new Scene(hBox,300,200));
            stage1.setTitle("ERROR");
            stage1.show();
            return false;//信息不全
        }
        return true;//信息全
    }

}