JTable 从 MySQL 数据库中获取值

Question

我需要从数据库中获取所有值并将其放入 JTable 中，填充所有行。 我的代码仅将最后一行放入 JTable 中，而错过了所有先前的行。 有人知道如何从数据库中获取所有值并将它们全部插入 JTable 中吗？

try{
            Class.forName("com.mysql.jdbc.Driver");
            conn3 = DriverManager.getConnection("jdbc:mysql://localhost/test1?user=me&password=123456");
            stmt3 = conn3.createStatement();
            rs3 = stmt3.executeQuery("SELECT * FROM teams");
            String str1 = null,str2 = null,str3 = null,str4 = null,str5 = null;
            while (rs3.next())
            {
                str1 = rs3.getString(1);
                str2 = rs3.getString(2);
                str3 = rs3.getString(3);
                str4 = rs3.getString(4);
                str5 = rs3.getString(5);
            }

            Object[][] data = {{str1,str2,str3,str4,str5}};
            String[] columnNames = {"id","Name","Players","Point","Position" };
            table = new JTable(data,columnNames);
            table.setCellSelectionEnabled(true);
            table.setColumnSelectionAllowed(true);
            table.setFillsViewportHeight(true);
            table.setSurrendersFocusOnKeystroke(true);
            table.setBounds(10, 321, 297, 143);
            frame.getContentPane().add(table);
            rs3.close();
            stmt3.close();
            conn3.close();
    }
    catch (SQLException se)
    {
        System.out.println( "SQL Exception:" );
           while( se != null )
           {
              System.out.println( "State  : " + se.getSQLState()  );
              System.out.println( "Message: " + se.getMessage()   );
              System.out.println( "Error  : " + se.getErrorCode() );
              se = se.getNextException();
           }
    }
    catch (ClassNotFoundException ex)
    {
           System.out.println("Error: unable to load driver class!");
    }

Answer 1

while (rs3.next())
        {
            str1 = rs3.getString(1);
            str2 = rs3.getString(2);
            str3 = rs3.getString(3);
            str4 = rs3.getString(4);
            str5 = rs3.getString(5);
        }

您一次又一次地覆盖相同的变量。您应该改用列表或数组。比如：

while (rs3.next())
        {
            //Given that all of your str are declared as List<String> strX = new List<String>();
            str1.add(rs3.getString(1));
            str2.add(rs3.getString(2));
            str3.add(rs3.getString(3));
            str4.add(rs3.getString(4)); 
            str5.add(rs3.getString(5));
        }

但是对于在表中插入 ResultSet 有 plenty of tutorials。

---

编辑：如果您不想使用表模型，您可以更改数据检索的逻辑。您必须向表格提供一个矩阵[行][列]。你的行是哪几行？你的列是哪一个？

行是结果集的“下一个”，而列是 1 到 5。您需要知道有多少行（有点棘手）：

if (rs3.next()) {
        rs3.last();
        int rows = rs3.getRow();
    }
rs3.beforeFirst();

现在创建矩阵：

String[][] matrix = new String[rows][4]; //Your Object[][] data.

int index = 0;
while(rs3.next()){
    matrix[i][0] = rs3.getString(1);
    matrix[i][1] = rs3.getString(2);
    matrix[i][2] = rs3.getString(3);
    matrix[i][3] = rs3.getString(4); 
    matrix[i][4] = rs3.getString(5);
    i++;
}
String[] columnNames = {"id","Name","Players","Point","Position" };
table = new JTable(matrix, columnNames);

---

有用：另一个有用（但不是严格要求）检索对象数据的方法是using customized mappings 或更复杂的对象关系映射框架，如Hibernate。

Answer 2

不要使用二维数组来保存数据。你不知道数据库中会有多少行数据，所以你不知道数组有多大。

查看Table From Database 以获得一些不同的建议。一种方法涉及使用向量，因此您可以使用 DefaultTableModel。

Answer 3

OP 代码使用二维对象数组作为 JTable 的数据，但从不将数据移动到该数组中。我们首先需要计算表中有多少行，以便我们确定数组的大小：

try {
        Class.forName("com.mysql.jdbc.Driver");
        conn3 = DriverManager.getConnection("jdbc:mysql://localhost/test1?user=me&password=123456");
        stmt3 = conn3.createStatement();
        ResultSet rowCounter = stmt3.executeQuery("SELECT COUNT(*) FROM teams");
        rowCounter.next();
        int numRows = rowCounter.getInt(1);
        stmt3.close();            
        Object[][] data = new Object[numRows][5];
        stmt3 = conn3.createStatement();
        rs3 = stmt3.executeQuery("SELECT * FROM teams");
        int row = 0;
        while (rs3.next()) {
            data[row][0] = rs3.getString(1);
            data[row][1] = rs3.getString(2);
            data[row][2] = rs3.getString(3);
            data[row][3] = rs3.getString(4);
            data[row][4] = rs3.getString(5);
            row++;
        }
        String[] columnNames = {"id","Name","Players","Point","Position" };
        table = new JTable(data,columnNames);
        table.setCellSelectionEnabled(true);
        table.setColumnSelectionAllowed(true);
        table.setFillsViewportHeight(true);
        table.setSurrendersFocusOnKeystroke(true);
        table.setBounds(10, 321, 297, 143);
        frame.getContentPane().add(table);
        rs3.close();
        stmt3.close();
        conn3.close();
}
catch (SQLException se) {
    //handle this
}
catch (ClassNotFoundException ex) {
       System.out.println("Error: unable to load driver class!");
}