This is a java fx program, rewrite SQLClient.java to display the query result in

ID: 3668827 • Letter: T

Question

This is a java fx program, rewrite SQLClient.java to display the query result in a TableView.

public class SQLClient extends Application {
// Connection to the database
private Connection connection;

// Statement to execute SQL commands
private Statement statement;

// Text area to enter SQL commands
private TextArea tasqlCommand = new TextArea();

// Text area to display results from SQL commands
private TextArea taSQLResult = new TextArea();

// DBC info for a database connection
private TextField tfUsername = new TextField();
private PasswordField pfPassword = new PasswordField();
private ComboBox<String> cboURL = new ComboBox<>();
private ComboBox<String> cboDriver = new ComboBox<>();

private Button btExecuteSQL = new Button("Execute SQL Command");
private Button btClearSQLCommand = new Button("Clear");
private Button btConnectDB = new Button("Connect to Database");
private Button btClearSQLResult = new Button("Clear Result");
private Label lblConnectionStatus
= new Label("No connection now");

@Override // Override the start method in the Application class
public void start(Stage primaryStage) {
    cboURL.getItems().addAll(FXCollections.observableArrayList(
      "jdbc:mysql://localhost/javabook",
      "jdbc:mysql://liang.armstrong.edu/javabook",
      "jdbc:odbc:exampleMDBDataSource",
      "jdbc:oracle:thin:@liang.armstrong.edu:1521:orcl"));
    cboURL.getSelectionModel().selectFirst();

    cboDriver.getItems().addAll(FXCollections.observableArrayList(
      "com.mysql.jdbc.Driver", "sun.jdbc.odbc.dbcOdbcDriver",
      "oracle.jdbc.driver.OracleDriver"));
    cboDriver.getSelectionModel().selectFirst();

    // Create UI for connecting to the database
    GridPane gridPane = new GridPane();
    gridPane.add(cboURL, 1, 0);
    gridPane.add(cboDriver, 1, 1);
    gridPane.add(tfUsername, 1, 2);
    gridPane.add(pfPassword, 1, 3);
    gridPane.add(new Label("JDBC Driver"), 0, 0);
    gridPane.add(new Label("Database URL"), 0, 1);
    gridPane.add(new Label("Username"), 0, 2);
    gridPane.add(new Label("Password"), 0, 3);

    HBox hBoxConnection = new HBox();
    hBoxConnection.getChildren().addAll(
      lblConnectionStatus, btConnectDB);
    hBoxConnection.setAlignment(Pos.CENTER_RIGHT);

    VBox vBoxConnection = new VBox(5);
    vBoxConnection.getChildren().addAll(
      new Label("Enter Database Information"),
      gridPane, hBoxConnection);

    gridPane.setStyle("-fx-border-color: black;");

    HBox hBoxSQLCommand = new HBox(5);
    hBoxSQLCommand.getChildren().addAll(
      btClearSQLCommand, btExecuteSQL);
    hBoxSQLCommand.setAlignment(Pos.CENTER_RIGHT);

    BorderPane borderPaneSqlCommand = new BorderPane();
    borderPaneSqlCommand.setTop(
      new Label("Enter an SQL Command"));
    borderPaneSqlCommand.setCenter(
      new ScrollPane(tasqlCommand));
    borderPaneSqlCommand.setBottom(
      hBoxSQLCommand);

    HBox hBoxConnectionCommand = new HBox(10);
    hBoxConnectionCommand.getChildren().addAll(
      vBoxConnection, borderPaneSqlCommand);

    BorderPane borderPaneExecutionResult = new BorderPane();
    borderPaneExecutionResult.setTop(
      new Label("SQL Execution Result"));
    borderPaneExecutionResult.setCenter(taSQLResult);
    borderPaneExecutionResult.setBottom(btClearSQLResult);

    BorderPane borderPane = new BorderPane();
    borderPane.setTop(hBoxConnectionCommand);
    borderPane.setCenter(borderPaneExecutionResult);

    // Create a scene and place it in the stage
    Scene scene = new Scene(borderPane, 670, 400);
    primaryStage.setTitle("SQLClient"); // Set the stage title
    primaryStage.setScene(scene); // Place the scene in the stage
    primaryStage.show(); // Display the stage

    btConnectDB.setOnAction(e -> connectToDB());
    btExecuteSQL.setOnAction(e -> executeSQL());
    btClearSQLCommand.setOnAction(e -> tasqlCommand.setText(null));
    btClearSQLResult.setOnAction(e -> taSQLResult.setText(null));
}

/** Connect to DB */
private void connectToDB() {
    // Get database information from the user input
    String driver = cboDriver
        .getSelectionModel().getSelectedItem();
    String url = cboURL.getSelectionModel().getSelectedItem();
    String username = tfUsername.getText().trim();
    String password = pfPassword.getText().trim();

    // Connection to the database
    try {
      Class.forName(driver);
      connection = DriverManager.getConnection(
        url, username, password);
      lblConnectionStatus.setText("Connected to " + url);
    }
    catch (java.lang.Exception ex) {
      ex.printStackTrace();
    }
}

/** Execute SQL commands */
private void executeSQL() {
    if (connection == null) {
      taSQLResult.setText("Please connect to a database first");
      return;
    }
    else {
      String sqlCommands = tasqlCommand.getText().trim();
      String[] commands = sqlCommands.replace(' ', ' ').split(";");

      for (String aCommand: commands) {
        if (aCommand.trim().toUpperCase().startsWith("SELECT")) {
          processSQLSelect(aCommand);
        }
        else {
          processSQLNonSelect(aCommand);
        }
      }
    }
}

/** Execute SQL SELECT commands */
private void processSQLSelect(String sqlCommand) {
    try {
      // Get a new statement for the current connection
      statement = connection.createStatement();

// Execute a SELECT SQL command
ResultSet resultSet = statement.executeQuery(sqlCommand);

      // Find the number of columns in the result set
      int columnCount = resultSet.getMetaData().getColumnCount();
      String row = "";

      // Display column names
      for (int i = 1; i <= columnCount; i++) {
        row += resultSet.getMetaData().getColumnName(i) + " ";
      }

taSQLResult.appendText(row + ' ');

      while (resultSet.next()) {
        // Reset row to empty
        row = "";

        for (int i = 1; i <= columnCount; i++) {
          // A non-String column is converted to a string
          row += resultSet.getString(i) + " ";
        }

        taSQLResult.appendText(row + ' ');
      }
    }
    catch (SQLException ex) {
      taSQLResult.setText(ex.toString());
    }
}

/** Execute SQL DDL, and modification commands */
private void processSQLNonSelect(String sqlCommand) {
    try {
      // Get a new statement for the current connection
      statement = connection.createStatement();

// Execute a non-SELECT SQL command
statement.executeUpdate(sqlCommand);

      taSQLResult.setText("SQL command executed");
    }
    catch (SQLException ex) {
      taSQLResult.setText(ex.toString());
    }
}

/**
   * The main method is only needed for the IDE with limited
   * JavaFX support. Not needed for running from the command line.
   */
public static void main(String[] args) {
    launch(args);
}
}

Explanation / Answer

Program for implementing Table view

Changed part is given in bold letters

import java.sql.*;
import javafx.application.Application;
import javafx.collections.FXCollections;
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.ScrollPane;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import java.sql.Connection;
import java.sql.ResultSet;
import javafx.beans.value.ObservableValue;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableColumn.CellDataFeatures;
import javafx.scene.control.TableView;
import javafx.collections.ObservableList;

public class SQLClient extends Application {

//table and data
    private ObservableList<ObservableList> data;
    private TableView tableDataView;

// Connection to the database
private Connection connection;

// Statement to execute SQL commands
private Statement statement;

// Text area to enter SQL commands
private TextArea tasqlCommand = new TextArea();

// Text area to display results from SQL commands
private TextArea taSQLResult = new TextArea();

/** Execute SQL SELECT commands */
private void processSQLSelect(String sqlCommand) {
    try {
      // Get a new statement for the current connection
      statement = connection.createStatement();

      // Execute a SELECT SQL command
      ResultSet resultSet = statement.executeQuery(sqlCommand);
      tableDataView = new TableView();

         // Dynamically adding table colums

       for(int i=0 ; i<resultSet.getMetaData().getColumnCount(); i++)
       {
           final int j = i;
           TableColumn cols = new TableColumn(resultSet.getMetaData().getColumnName(i+1));
           cols.setCellValueFactory(new Callback<CellDataFeatures<ObservableList,String>,ObservableValue<String>>()
           {
               public ObservableValue<String> call(CellDataFeatures<ObservableList, String> param)
               {
                   return new SimpleStringProperty(param.getValue().get(j).toString());
               }
           });

           tableDataView.getColumns().addAll(cols);
           System.out.println("Column ["+i+"] ");
       }

       // Adding data to observable list
       while(resultSet.next())
       {
           //Iterate Row
           ObservableList<String> row = FXCollections.observableArrayList();
           for(int i=1 ; i<=resultSet.getMetaData().getColumnCount(); i++){
               //Iterate Column
               row.add(resultSet.getString(i));
           }
           System.out.println("Row [1] added "+row );
           data.add(row);

}

       data is being added to table view
       tableDataView.setItems(data);

    }
    catch (Exception ex) {
      taSQLResult.setText(ex.toString());
    }
}

// Execute a non-SELECT SQL command
statement.executeUpdate(sqlCommand);

      taSQLResult.setText("SQL command executed");
    }
    catch (SQLException ex) {
      taSQLResult.setText(ex.toString());
    }
}

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This is a java fx program, rewrite SQLClient.java to display the query result in

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