0
我有一個代碼在'mysql'數據庫中輸入一些數據到'createaccount'表中。我使用NetBeans IDE創建了它。表和數據庫都被創建。每當我運行代碼時，都會顯示「沒有選擇數據庫」的SQLException。我將在下面提供我的代碼。爲什麼會顯示此錯誤？我應該怎麼做才能解決它？爲什麼「沒有選擇數據庫」SQLException顯示
package login;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.geometry.Insets;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ComboBox;
import javafx.scene.control.Label;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;
import javafx.stage.Stage;
public class Login extends Application {
TextField t1,t2;
PasswordField t3;
ComboBox comboBox2;
private Connection connect = null;
private Statement statement = null;
private PreparedStatement preparedStatement = null;
@Override
public void start(Stage stage) {
BorderPane border = new BorderPane();
border.setTop(loginHBox1());
border.setLeft(loginVBox1());
border.setRight(loginVBox2());
Scene scene = new Scene(border,700,450);
stage.setScene(scene);
stage.setResizable(false);
scene.getStylesheets().add
(Login.class.getResource("Login.css").toExternalForm());
stage.show();
}
private HBox loginHBox1() {
HBox hbox = new HBox();
hbox.setPadding(new Insets(15, 12, 10, 180));
hbox.setSpacing(10); // Gap between nodes
Label lb1=new Label("LOG IN OR CREATE NEW ACCOUNT");
lb1.setAlignment(Pos.CENTER);
lb1.setFont(Font.font("Calibri",FontWeight.BOLD,26));
lb1.setTextFill(Color.BLACK);
hbox.getChildren().addAll(lb1);
return hbox;
}
private VBox loginVBox1() {
VBox hbox = new VBox();
hbox.setPadding(new Insets(20,30,15,50)); // Set all sides to 10
hbox.setSpacing(10); // Gap between nodes
Label lb3=new Label("LOG IN");
lb3.setAlignment(Pos.CENTER);
lb3.setFont(Font.font("Calibri",FontWeight.BOLD,24));
lb3.setTextFill(Color.BLACK);
Label lb1=new Label("Username");
lb1.setAlignment(Pos.CENTER);
lb1.setFont(Font.font("Calibri",FontWeight.BOLD,16));
lb1.setTextFill(Color.BLACK);
TextField t11=new TextField();
t11.setPrefSize(150,30);
Label lb2=new Label("Password");
lb2.setAlignment(Pos.CENTER);
lb2.setFont(Font.font("Calibri",FontWeight.BOLD,16));
lb2.setTextFill(Color.BLACK);
PasswordField pw11=new PasswordField();
pw11.setPrefSize(150,30);
Button b1=new Button("LOG IN");
b1.setFont(Font.font("Calibri",FontWeight.BOLD,16));
b1.setPrefSize(80,5);
hbox.getChildren().addAll(lb3,lb1,t11,lb2,pw11,b1);
return hbox;
}
private VBox loginVBox2()
{
VBox hbox1 = new VBox();
hbox1.setPadding(new Insets(15, 50, 15, 10));
hbox1.setSpacing(10);
Label lb4=new Label("CREATE NEW ACCOUNT");
lb4.setFont(Font.font("Calibri",FontWeight.BOLD,24));
lb4.setPrefSize(250,30);
lb4.setTextFill(Color.BLACK);
Label lb1=new Label("Full Name ");
lb1.setFont(Font.font("Calibri",FontWeight.BOLD,18));
lb1.setPrefSize(100, 30);
lb1.setTextFill(Color.BLACK);
t1=new TextField();
t1.setPrefSize(50,30);
Label lb2=new Label("User Name ");
lb2.setFont(Font.font("Calibri",FontWeight.BOLD,18));
lb2.setPrefSize(150, 30);
lb2.setTextFill(Color.BLACK);
t2=new TextField();
t2.setPrefSize(100,30);
Label lb3=new Label("Password ");
lb3.setFont(Font.font("Calibri",FontWeight.BOLD,18));
lb3.setPrefSize(150, 30);
lb3.setTextFill(Color.BLACK);
t3=new PasswordField();
t3.setPrefSize(100,30);
Label lb5=new Label("Gender ");
lb5.setFont(Font.font("Calibri",FontWeight.BOLD,18));
lb5.setPrefSize(150, 30);
lb5.setTextFill(Color.BLACK);
ObservableList<String> options2 =
FXCollections.observableArrayList(
"Male","Female");
comboBox2 = new ComboBox(options2);
comboBox2.setPrefSize(250,30);
Button btn1=new Button("CREATE");
btn1.setFont(Font.font("Calibri",FontWeight.BOLD,18));
btn1.setPrefSize(100,30);
btn1.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent e) {
try {
createAccount();
} catch ( ClassNotFoundException | SQLException ex) {
Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
hbox1.getChildren().addAll(lb4,lb1,t1,lb2,t2,lb3,t3,lb5,comboBox2,btn1);
return hbox1;
}
public void createAccount() throws ClassNotFoundException, SQLException
{
try {
// This will load the MySQL driver, each DB has its own driver
Class.forName("com.mysql.jdbc.Driver");
// Setup the connection with the DB
connect = DriverManager
.getConnection("jdbc:mysql://localhost:3306/mysql?"
+ "user=root&password=virus");
// Statements allow to issue SQL queries to the database
statement = connect.createStatement();
// PreparedStatements can use variables and are more efficient
preparedStatement = connect
.prepareStatement("insert into createaccount values (?, ?, ?, ?)");
// "myuser, webpage, datum, summary, COMMENTS from FEEDBACK.COMMENTS");
// Parameters start with 1
preparedStatement.setString(1, "Tomin Jacob");
preparedStatement.setString(2, "Tom333");
preparedStatement.setString(3, "pass");
preparedStatement.setString(4, "male");
preparedStatement.executeUpdate();
}
catch (ClassNotFoundException | SQLException e) {
throw e;
} finally {
close();
}
}
private void close() {
try {
if (statement != null) {
statement.close();
}
if (connect != null) {
connect.close();
}
} catch (SQLException e) {
}
}
public static void main(String[] args)
{
launch(args);
}
}
-1，用於發佈很多與您的問題無關的代碼。請將代碼簡化爲重現此問題所需的內容。 –
@MarkRotteveel好的...我會在下次做。 – TomJ