无法解析JTable构造方法：ArrayList参数传入报错求助

我编写了如下Rentals类：

public class Rentals {
    protected int RentalID;
    protected int CustomerID;
    protected int MovieID;
    protected Date DateRented;
    protected Date DateDue;

    public Rentals(int rentalID, int customerID, int movieID, Date dateRented, Date dateDue) {
        RentalID = rentalID;
        CustomerID = customerID;
        MovieID = movieID;
        DateRented = dateRented;
        DateDue = dateDue;
    }

    public int getRentalID() {
        return RentalID;
    }

    public void setRentalID(int rentalID) {
        RentalID = rentalID;
    }

    public int getCustomerID() {
        return CustomerID;
    }

    public void setCustomerID(int customerID) {
        CustomerID = customerID;
    }

    public int getMovieID() {
        return MovieID;
    }

    public void setMovieID(int movieID) {
        MovieID = movieID;
    }

    public Date getDateRented() {
        return DateRented;
    }

    public void setDateRented(Date dateRented) {
        DateRented = dateRented;
    }

    public Date getDateDue() {
        return DateDue;
    }

    public void setDateDue(Date dateDue) {
        DateDue = dateDue;
    }
}

在Main类中，我创建了两个ArrayList：存储Rentals对象的RentalList和存储列名的Columns，还定义了JTable对象Display。随后连接MS Azure SQL数据库，将查询数据存入这两个集合。尝试用这两个集合实例化Display时，出现如下错误：

java: no suitable constructor found for JTable(java.util.ArrayList<com.company.Rentals>,java.util.ArrayList<java.lang.String>)
    constructor javax.swing.JTable.JTable(javax.swing.table.TableModel,javax.swing.table.TableColumnModel) is not applicable
      (argument mismatch; java.util.ArrayList<com.company.Rentals> cannot be converted to javax.swing.table.TableModel)
    constructor javax.swing.JTable.JTable(int,int) is not applicable
      (argument mismatch; java.util.ArrayList<com.company.Rentals> cannot be converted to int)
    constructor javax.swing.JTable.JTable(java.util.Vector,java.util.Vector) is not applicable
      (argument mismatch; java.util.ArrayList<com.company.Rentals> cannot be converted to java.util.Vector)
    constructor javax.swing.JTable.JTable(java.lang.Object[][],java.lang.Object[]) is not applicable
      (argument mismatch; java.util.ArrayList<com.company.Rentals> cannot be converted to java.lang.Object[][])

报错代码行：Display = new JTable(RentalList, Columns);

Main类代码：

public class Main {
    public static JTable Display;
    public static ArrayList<Rentals> RentalList =  new ArrayList<Rentals>();
    public static ArrayList<String> Columns = new ArrayList<String>();

    public static void main(String[] args) {
        String ConnectionURL = "___"; //HIDDEN, IN THE ACTUAL CODE IT DOES CONNECT
        ResultSet rs;

        // Open a connection
        try(Connection conn = DriverManager.getConnection(ConnectionURL);
            Statement stmt = conn.createStatement();
        ) {
            rs = stmt.executeQuery("SELECT * FROM [dbo].[Rentals]");
            while (rs.next()) {
                Rentals rental = new Rentals(0, 0, 0, null, null);
                rental.setRentalID(rs.getInt(1));
                rental.setCustomerID(rs.getInt(2));
                rental.setMovieID(rs.getInt(3));
                rental.setDateRented(rs.getDate(4));
                rental.setDateDue(rs.getDate(5));
                RentalList.add(rental);
            }
            
            rs = stmt.executeQuery("SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = N'Rentals'");
            while (rs.next()) {
                Columns.add(rs.getString(1));
            }
        }
        catch (SQLException e) {
            e.printStackTrace();
        }

        Display = new JTable(RentalList, Columns);
    }
}

我尝试改成Display = new JTable(RentalList.toString(), Columns);但错误依旧。请问我哪里操作有误？如何修正这个问题？

错误原因 #

JTable没有直接接收ArrayList<Rentals>和ArrayList<String>的构造方法。从报错信息可知，JTable仅支持以下几种参数类型的构造方法：

• TableModel + TableColumnModel
• 行列数量（int类型）
• Vector + Vector
• Object[][] + Object[]

传入的ArrayList<Rentals>是自定义对象集合，JTable无法直接解析其中的属性作为表格行数据；调用toString()也无效，因为这只是将集合转为字符串，依然不符合构造方法的参数要求。

修正方案 #

方案1：转换为Object[][]和Object[]格式 #

将RentalList中的每个Rentals对象拆分为一维数组，再组合成二维数组，列名转换为Object[]类型：

// 转换行数据为二维数组
Object[][] rowData = new Object[RentalList.size()][5];
for (int i = 0; i < RentalList.size(); i++) {
    Rentals rental = RentalList.get(i);
    rowData[i][0] = rental.getRentalID();
    rowData[i][1] = rental.getCustomerID();
    rowData[i][2] = rental.getMovieID();
    rowData[i][3] = rental.getDateRented();
    rowData[i][4] = rental.getDateDue();
}

// 转换列名为Object数组
Object[] columnNames = Columns.toArray(new Object[Columns.size()]);

// 实例化JTable
Display = new JTable(rowData, columnNames);

方案2：自定义TableModel（推荐） #

继承AbstractTableModel，将RentalList和Columns作为数据源，重写必要方法。这种方式实现数据与视图分离，后续维护和扩展更方便：

import javax.swing.table.AbstractTableModel;
import java.util.ArrayList;

public class RentalTableModel extends AbstractTableModel {
    private ArrayList<Rentals> rentalList;
    private ArrayList<String> columnNames;

    public RentalTableModel(ArrayList<Rentals> rentalList, ArrayList<String> columnNames) {
        this.rentalList = rentalList;
        this.columnNames = columnNames;
    }

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

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

    @Override
    public String getColumnName(int column) {
        return columnNames.get(column);
    }

    @Override
    public Object getValueAt(int rowIndex, int columnIndex) {
        Rentals rental = rentalList.get(rowIndex);
        switch (columnIndex) {
            case 0: return rental.getRentalID();
            case 1: return rental.getCustomerID();
            case 2: return rental.getMovieID();
            case 3: return rental.getDateRented();
            case 4: return rental.getDateDue();
            default: return null;
        }
    }
}

在Main类中使用自定义模型实例化JTable：

// 创建自定义TableModel
RentalTableModel model = new RentalTableModel(RentalList, Columns);
// 实例化JTable
Display = new JTable(model);

方案对比 #

• 方案1适合简单场景，但如果Rentals类属性变更，需要手动修改数组转换逻辑；
• 方案2遵循MVC设计思想，代码可维护性更强，是Swing开发中的标准做法。

内容的提问来源于stack exchange，提问作者Slappy