java - JTable:选择一行时从数据库中获取值

Question

我有三个文件，TopicData、TopicView、TopicTableModel。我的程序使用数据库中的值显示一个表。现在，当我单击一行时，会打印该行的索引。 我想修改代码，改为打印我数据库中的 topicID。topicID 的值存储在 ArrayList 中但不显示在表中，因此我不能使用 JTable.getValueAt( ).

请指教如何修改我的代码。提前致谢。

更多信息:

1. TopicData 从数据库中获取数据并将其存储在 ArrayList 中。

2. 然后将 ArrayList 传递给 TopicTableModel，其中数据适合在 JTable 中显示。

3. TopicView 创建一个 JTable 并接收 TopicTableModel 以生成 JTable。

主题数据.java

public class TopicData {
int id;
String name; 
String date; 
String category;
String user;

public TopicData(){
}

public TopicData(int id, String name, String date, String category, String user) {
    this.id = id;
    this.name = name;
    this.date = date;
    this.category = category;
    this.user = user;
}



public TopicData(String name, String date, String category, String user) {
    this.name = name;
    this.date = date;
    this.category = category;
    this.user = 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 getDate() {
    return date;
}

public void setDate(String date) {
    this.date = date;
}

public String getCategory() {
    return category;
}

public void setCategory(String category) {
    this.category = category;
}

public String getUser() {
    return user;
}

public void setUser(String user) {
    this.user = user;
}


public ArrayList<TopicData> getTopicList(){
    ArrayList<TopicData> topicList = new ArrayList<TopicData>();
    ResultSet rs = null;
    DBController db = new DBController();
    db.setUp("myDatabase");
    String dbQuery = "SELECT topicID, topicName, topicDate, topicCategory, topicUser FROM topicTable ORDER BY topicDate";

    rs = db.readRequest(dbQuery);

    try{
        while(rs.next()){
            int id = rs.getInt("topicID");
            String name = rs.getString("topicName"); 
            String date = rs.getString("topicDate") ; 
            String category = rs.getString("topicCategory");
            String user = rs.getString("topicUser");

            TopicData topic = new TopicData (id, name, date, category, user);
            topicList.add(topic);
        }
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    db.terminate();
    return topicList;
}

主题表模型.java

public class TopicTableModel extends AbstractTableModel {

private static final long serialVersionUID = 1L;
private int rowCount, colCount;
private String[] columnNames = {"Name", "Date", "User"};
private Object [][] data;

public TopicTableModel(ArrayList<TopicData> listOfObjects) {
    rowCount = listOfObjects.size();
    colCount = columnNames.length;
    data = new Object[rowCount][colCount];

    for (int i = 0; i < rowCount; i++) {
        //Copy an ArrayList element to an instance of MyObject
        TopicData topic = (listOfObjects.get(i)); 
        data[i][0] = topic.getName();            
        data[i][1] = topic.getDate();
        data[i][2] = topic.getUser();
    }              
} 

@Override
public int getColumnCount() {
    // TODO Auto-generated method stub
    return colCount;
}

@Override
public int getRowCount() {
    // TODO Auto-generated method stub
    return rowCount;
}

@Override
public String getColumnName(int col) {
    return columnNames[col];
}

@Override
public Object getValueAt(int rowIndex, int columnIndex) {
    // TODO Auto-generated method stub
    return data[rowIndex][columnIndex];
}

@Override
public boolean isCellEditable(int rowIndex, int colIndex) {
    return false; //Disallow the editing of any cell
}

}

主题 View .java

private JTable getTable() {
    if (table == null) {
        TopicData topic= new TopicData();
        TopicTableModel tableModel = new TopicTableModel(topic.getTopicList());
        table = new JTable(tableModel);

        table.setShowGrid(false);
        table.setFillsViewportHeight(true);
        table.setBounds(173, 87, 456, 263);
        table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        table.getTableHeader().setReorderingAllowed(false);
        table.getTableHeader().setResizingAllowed(false);
        table.getColumnModel().getColumn(0).setPreferredWidth(500);

        ListSelectionModel rowSM = table.getSelectionModel();
        rowSM.addListSelectionListener(new ListSelectionListener() {
            public void valueChanged(ListSelectionEvent e) {
                //Ignore extra messages.
                if (e.getValueIsAdjusting()) return;

                ListSelectionModel lsm = (ListSelectionModel)e.getSource();
                if (lsm.isSelectionEmpty()) {
                    System.out.println("No rows are selected.");
                } 
                else {
                    int selectedRow = lsm.getMinSelectionIndex();
                    System.out.println("Row " + selectedRow + " is now selected.");
                }
            }
        });
    }
    return table;
}

Answer 1

您正在以艰难的方式做到这一点。无需将 TopicData 转换为数组，只需让您的 TableModel 直接读取 TopicData 对象的 ArrayList，因此每个 TopicData 对应一行。

主题表模型.java:

import java.util.ArrayList;

import javax.swing.table.AbstractTableModel;

public class TopicTableModel extends AbstractTableModel {

private static final long serialVersionUID = 1L;
private String[] columnNames = {"Name", "Date", "User"};
private ArrayList<TopicData> data;

public TopicTableModel(ArrayList<TopicData> listOfObjects) {
    data = listOfObjects;
} 

@Override
public int getColumnCount() {
    return columnNames.length;
}

@Override
public int getRowCount() {
    return data.size();
}

@Override
public String getColumnName(int col) {
    return columnNames[col];
}

@Override
public Object getValueAt(int rowIndex, int columnIndex) {
    switch (column) {
    case 0:
        return data.getName();
    case 1:
        return data.getDate();
    case 2:
        return data.getUser();
    default:
        throw new ArrayIndexOutOfBoundsException();
    }
}

@Override
public boolean isCellEditable(int rowIndex, int colIndex) {
    return false; //Disallow the editing of any cell
}

public TopicData getTopic(int row) {
    return data.get(row);
}

}

通过对 TopicView.java 进行一些小的修改，您现在可以获取所选行的 TopicData 并打印其 ID。

主题 View .java:

import javax.swing.JTable;
import javax.swing.ListSelectionModel;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;


public class TopicView {
    JTable table;

    private JTable getTable() {
        if (table == null) {
            TopicData topic= new TopicData();
            final TopicTableModel tableModel = new TopicTableModel(topic.getTopicList());
            table = new JTable(tableModel);

            table.setShowGrid(false);
            table.setFillsViewportHeight(true);
            table.setBounds(173, 87, 456, 263);
            table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
            table.getTableHeader().setReorderingAllowed(false);
            table.getTableHeader().setResizingAllowed(false);
            table.getColumnModel().getColumn(0).setPreferredWidth(500);
            table.setDefaultRenderer(TopicData.class, new TopicDataTableCellRenderer());

            ListSelectionModel rowSM = table.getSelectionModel();
            rowSM.addListSelectionListener(new ListSelectionListener() {
                public void valueChanged(ListSelectionEvent e) {
                    //Ignore extra messages.
                    if (e.getValueIsAdjusting()) return;

                    int row = table.getSelectedRow();
                    if (row < 0) {
                        System.out.println("No rows are selected.");
                    }
                    else {
                        System.out.println("id " + tableModel.getTopic(row).getId() + " is now selected.");
                    }
                }
            });
        }
        return table;
    }
}