我的代码应通过loadCusotmerTable()方法从具有JDBC的MYSQL数据库中通过CustomerDOA.findAll()在javafx中加载客户表视图。 findAll()方法返回应显示客户的ObservableList。
Table输出当前在ObservableList中为每个客户显示正确的行数，但是它仅显示ObservableList中最后一个条目的数据。我的代码中缺少正确加载ObservableList<Customer> Customers的内容吗？
loadCustomerTable
package Controller;
import Model.Customer;
import Model.DAO.CustomerDAO;
import Model.DAO.UserDAO;
import Model.DBConnection;
import java.io.IOException;
import java.net.URL;
import java.sql.Connection;
import java.sql.SQLException;
import java.time.LocalDateTime;
import java.util.HashSet;
import java.util.ResourceBundle;
import java.util.Set;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.MenuButton;
import javafx.scene.control.MenuItem;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.stage.Stage;
public class CustomerViewController implements Initializable {
@FXML private TextField TextFieldCustomerID;
@FXML private TextField TextFieldCustomerName;
@FXML private Button ButtonGoBack;
@FXML private Button ButtonAddModify;
@FXML private Button ButtonRemove;
@FXML private Button ButtonCancel;
@FXML private MenuButton MenuButtonAddress;
@FXML private MenuButton MenuButtonActive;
@FXML private MenuItem MenuActiveItemActive;
@FXML private MenuItem MenuActiveItemInactive;
@FXML private TableView<Customer> TableViewCustomer;
@FXML private TableColumn<Customer, String> TableCustomerColumnCustomerID;
@FXML private TableColumn<Customer, String> TableCustomerColumnCustomerName;
@FXML private TableColumn<Customer, String> TableCustomerColumnAddress;
@FXML private TableColumn<Customer, String> TableCustomerColumnActive;
private int addressId = 1;
private int Active = 1;
private int userId = 1;
private boolean isCustomerSelected = true;
private ObservableList<Customer> Customers = FXCollections.observableArrayList();
// .......
public void loadCustomerTable(){
CustomerDAO customerDAO = new CustomerDAO(DBConnection.getConnection());
ObservableList<Customer> Customers = customerDAO.findAll();
TableCustomerColumnCustomerID.setCellValueFactory(new PropertyValueFactory<>("customerId"));
TableCustomerColumnCustomerName.setCellValueFactory(new PropertyValueFactory<>("customerName"));
TableCustomerColumnAddress.setCellValueFactory(new PropertyValueFactory<>("addressId"));
TableCustomerColumnActive.setCellValueFactory(new PropertyValueFactory<>("active"));
TableViewCustomer.setItems(Customers);
}
CustomerDAO.findAll（）
public ObservableList<Customer> findAll() {
ObservableList<Customer> Customers = FXCollections.observableArrayList();
Customer customer = new Customer();
try(PreparedStatement statement = this.connection.prepareStatement(GET_ALL)){
ResultSet resultSet = statement.executeQuery();
int i =0;
while(resultSet.next()){
customer.setCustomerId(resultSet.getInt("customerId"));
customer.setCustomerName(resultSet.getString("customerName"));
customer.setAddressId(resultSet.getInt("addressId"));
customer.setActive(resultSet.getInt("active"));
customer.setCreateDate(resultSet.getTimestamp("createDate"));
customer.setLastUpdate(resultSet.getTimestamp("lastUpdate"));
customer.setCreatedBy(resultSet.getString("createdBy"));
customer.setLastUpdateBy(resultSet.getString("lastUpdateBy"));
Customers.add(customer);
System.out.println(Customers.get(i).getCustomerName());
i++;
}
}catch(SQLException e){
e.printStackTrace();
throw new RuntimeException(e);
}
return Customers;
}
客户类别
import Utils.DataTransferObject;
import java.sql.Timestamp;
import java.time.LocalDateTime;
import java.util.Date;
import javafx.beans.property.IntegerProperty;
public class Customer implements DataTransferObject {
private int customerId;
private String customerName; //varchar 45
private int addressId;
private int active; // tiny int 1
private LocalDateTime createDate;
private LocalDateTime lastUpdate;
private String createdBy;
private String lastUpdateBy;
@Override
public long getId() {
return customerId;
}
public int getCustomerId() {
return customerId;
}
public void setCustomerId(int customerId) {
this.customerId = customerId;
}
public String getCustomerName() {
return customerName;
}
public void setCustomerName(String customerName) {
this.customerName = customerName;
}
public int getAddressId() {
return addressId;
}
public void setAddressId(int addressId) {
this.addressId = addressId;
}
public int getActive() {
return active;
}
public void setActive(int active) {
this.active = active;
}
public LocalDateTime getCreateDate() {
return createDate;
}
public void setCreateDate(LocalDateTime createDate) {
this.createDate = createDate;
}
public void setCreateDate(Timestamp createDate) {
this.createDate = createDate.toLocalDateTime();
}
public LocalDateTime getLastUpdate() {
return lastUpdate;
}
public void setLastUpdate(LocalDateTime lastUpdate) {
this.lastUpdate = lastUpdate;
}
public void setLastUpdate(Timestamp lastUpdate) {
this.lastUpdate = lastUpdate.toLocalDateTime();
}
public String getCreatedBy() {
return createdBy;
}
public void setCreatedBy(String createdBy) {
this.createdBy = createdBy;
}
public String getLastUpdateBy() {
return lastUpdateBy;
}
public void setLastUpdateBy(String lastUpdateBy) {
this.lastUpdateBy = lastUpdateBy;
}
}
最佳答案
您的CustomerDAO.findAll()方法反复将相同的Customer实例添加到表中（每次都更改单个对象中的数据）。因此，该表包含对同一对象的多个引用。
内存图片如下：
由于只有一个Customer对象，因此只有一个customerId，一个customerName等，并且列表中的每个元素都引用相同的值。
而是每次都创建一个新的Customer，并将其添加到列表中。然后，内存图片如下所示：
public ObservableList<Customer> findAll() {
ObservableList<Customer> customers = FXCollections.observableArrayList();
try(PreparedStatement statement = this.connection.prepareStatement(GET_ALL)){
ResultSet resultSet = statement.executeQuery();
int i =0;
while(resultSet.next()){
// This line moved inside the loop, to create a new
// object on each iteration:
Customer customer = new Customer();
customer.setCustomerId(resultSet.getInt("customerId"));
customer.setCustomerName(resultSet.getString("customerName"));
customer.setAddressId(resultSet.getInt("addressId"));
customer.setActive(resultSet.getInt("active"));
customer.setCreateDate(resultSet.getTimestamp("createDate"));
customer.setLastUpdate(resultSet.getTimestamp("lastUpdate"));
customer.setCreatedBy(resultSet.getString("createdBy"));
customer.setLastUpdateBy(resultSet.getString("lastUpdateBy"));
customers.add(customer);
System.out.println(customers.get(i).getCustomerName());
i++;
}
}catch(SQLException e){
e.printStackTrace();
throw new RuntimeException(e);
}
return customers;
}