我正在编写一个程序，当输入医师号（FHIR HAPI）时显示病人记录，但这不是重点。我想显示病人的基本信息，然后通过一个复选框，允许用户在JTable中添加一个额外的列来显示他们的详细信息。
这个额外的列应该可以根据复选框的状态进行添加和删除。然而，当我尝试使用我的 DefaultTableModel 变量来执行 model.addColumn() 方法，我总是得到一个 NullPointer 异常。
最后一个方法是产生问题的方法。我还提供了被调用的其他方法的代码。我尝试了使用各种类型的数组（Object和String）作为值，甚至是数组列表。你还会看到，在我的第二个方法的代码中，你会看到 getAllPatientObservationValues() 我执行了一个println看看是否进入方法，没有。任何帮助将非常感激。
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionListener;
import java.text.ParseException;
public class GUIManager extends JFrame{
private Operations op;
private JPanel pnPnlMain;
private JPanel pnPnlTop;
private JCheckBox cbChkCholesterol;
private JPanel pnPnlMiddle;
private JTable tblLeft;
private DefaultTableModel tblLeftModel;
private JTable tblRight;
private DefaultTableModel tblRightModel;
private JButton btBtnAdd;
private JButton btBtnRemove;
private JPanel pnPnlBottom;
private JButton btBtnExit;
private JLabel lbLblTime;
private JTextField tfTxtSeconds;
private JLabel lbLblThreshhold;
private JTextField tfTxtThreshold;
public GUIManager(Operations inOP)
{
setSize(1000, 650);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("FHIR Patient Monitor");
pnPnlMain = new JPanel();
pnPnlMain.setBorder( BorderFactory.createTitledBorder( "FHIR" ) );
GridBagLayout gbPnlMain = new GridBagLayout();
GridBagConstraints gbcPnlMain = new GridBagConstraints();
pnPnlMain.setLayout( gbPnlMain );
pnPnlTop = new JPanel();
pnPnlTop.setBorder( BorderFactory.createTitledBorder( "Column Details" ) );
GridBagLayout gbPnlTop = new GridBagLayout();
GridBagConstraints gbcPnlTop = new GridBagConstraints();
pnPnlTop.setLayout( gbPnlTop );
cbChkCholesterol = new JCheckBox( "Cholesterol");
gbcPnlTop.gridx = 2;
gbcPnlTop.gridy = 1;
gbcPnlTop.gridwidth = 6;
gbcPnlTop.gridheight = 1;
gbcPnlTop.fill = GridBagConstraints.BOTH;
gbcPnlTop.weightx = 1;
gbcPnlTop.weighty = 0;
gbcPnlTop.anchor = GridBagConstraints.NORTH;
gbPnlTop.setConstraints( cbChkCholesterol, gbcPnlTop );
pnPnlTop.add( cbChkCholesterol );
gbcPnlMain.gridx = 0;
gbcPnlMain.gridy = 0;
gbcPnlMain.gridwidth = 20;
gbcPnlMain.gridheight = 4;
gbcPnlMain.fill = GridBagConstraints.BOTH;
gbcPnlMain.weightx = 1;
gbcPnlMain.weighty = 0;
gbcPnlMain.anchor = GridBagConstraints.NORTH;
gbPnlMain.setConstraints( pnPnlTop, gbcPnlMain );
pnPnlMain.add( pnPnlTop );
pnPnlMiddle = new JPanel();
pnPnlMiddle.setBorder( BorderFactory.createTitledBorder( "Tables" ) );
GridBagLayout gbPnlMiddle = new GridBagLayout();
GridBagConstraints gbcPnlMiddle = new GridBagConstraints();
pnPnlMiddle.setLayout( gbPnlMiddle );
String [][]dataTblLeft = new String[1][2];
String []colsTblLeft = new String[] { "ID", "Full Name" };
tblLeftModel = new DefaultTableModel(dataTblLeft, colsTblLeft);
tblLeft = new JTable(tblLeftModel);
tblLeftModel.removeRow(0);
JScrollPane scpLeftTable = new JScrollPane(tblLeft);
scpLeftTable.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
scpLeftTable.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
gbcPnlMiddle.gridx = 0;
gbcPnlMiddle.gridy = 0;
gbcPnlMiddle.gridwidth = 9;
gbcPnlMiddle.gridheight = 12;
gbcPnlMiddle.fill = GridBagConstraints.NONE;
gbcPnlMiddle.weightx = 1;
gbcPnlMiddle.weighty = 1;
gbcPnlMiddle.anchor = GridBagConstraints.CENTER;
gbPnlMiddle.setConstraints( scpLeftTable, gbcPnlMiddle );
pnPnlMiddle.add(scpLeftTable);
String [][]dataTblRight = new String[1][7] ;
String []colsTblRight = new String[] { "ID", "Full Name", "Birthdate","Gender","City","State","Country"};
tblRightModel = new DefaultTableModel(dataTblRight, colsTblRight);
tblRight = new JTable(tblRightModel);
tblRight.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
tblRightModel.removeRow(0);
JScrollPane scpRightTable = new JScrollPane(tblRight);
scpRightTable.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
scpRightTable.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
gbcPnlMiddle.gridx = 10;
gbcPnlMiddle.gridy = 0;
gbcPnlMiddle.gridwidth = 9;
gbcPnlMiddle.gridheight = 12;
gbcPnlMiddle.fill = GridBagConstraints.NONE;
gbcPnlMiddle.weightx = 1;
gbcPnlMiddle.weighty = 1;
gbcPnlMiddle.anchor = GridBagConstraints.CENTER;
gbPnlMiddle.setConstraints( scpRightTable, gbcPnlMiddle );
pnPnlMiddle.add( scpRightTable );
btBtnAdd = new JButton( "Add" );
gbcPnlMiddle.gridx = 2;
gbcPnlMiddle.gridy = 12;
gbcPnlMiddle.gridwidth = 5;
gbcPnlMiddle.gridheight = 2;
gbcPnlMiddle.fill = GridBagConstraints.NONE;
gbcPnlMiddle.weightx = 1;
gbcPnlMiddle.weighty = 0;
gbcPnlMiddle.anchor = GridBagConstraints.NORTH;
gbPnlMiddle.setConstraints( btBtnAdd, gbcPnlMiddle );
pnPnlMiddle.add( btBtnAdd );
btBtnRemove = new JButton( "Remove" );
gbcPnlMiddle.gridx = 12;
gbcPnlMiddle.gridy = 12;
gbcPnlMiddle.gridwidth = 5;
gbcPnlMiddle.gridheight = 2;
gbcPnlMiddle.fill = GridBagConstraints.NONE;
gbcPnlMiddle.weightx = 1;
gbcPnlMiddle.weighty = 0;
gbcPnlMiddle.anchor = GridBagConstraints.NORTH;
gbPnlMiddle.setConstraints( btBtnRemove, gbcPnlMiddle );
pnPnlMiddle.add( btBtnRemove );
gbcPnlMain.gridx = 0;
gbcPnlMain.gridy = 4;
gbcPnlMain.gridwidth = 20;
gbcPnlMain.gridheight = 15;
gbcPnlMain.fill = GridBagConstraints.BOTH;
gbcPnlMain.weightx = 1;
gbcPnlMain.weighty = 0;
gbcPnlMain.anchor = GridBagConstraints.NORTH;
gbPnlMain.setConstraints( pnPnlMiddle, gbcPnlMain );
pnPnlMain.add( pnPnlMiddle );
pnPnlBottom = new JPanel();
GridBagLayout gbPnlBottom = new GridBagLayout();
GridBagConstraints gbcPnlBottom = new GridBagConstraints();
pnPnlBottom.setLayout( gbPnlBottom );
btBtnExit = new JButton( "Exit" );
gbcPnlBottom.gridx = 16;
gbcPnlBottom.gridy = 0;
gbcPnlBottom.gridwidth = 4;
gbcPnlBottom.gridheight = 2;
gbcPnlBottom.fill = GridBagConstraints.NONE;
gbcPnlBottom.weightx = 1;
gbcPnlBottom.weighty = 0;
gbcPnlBottom.anchor = GridBagConstraints.EAST;
gbPnlBottom.setConstraints( btBtnExit, gbcPnlBottom );
pnPnlBottom.add( btBtnExit );
lbLblTime = new JLabel( "Refresh Rate:" );
gbcPnlBottom.gridx = 0;
gbcPnlBottom.gridy = 0;
gbcPnlBottom.gridwidth = 6;
gbcPnlBottom.gridheight = 1;
gbcPnlBottom.fill = GridBagConstraints.BOTH;
gbcPnlBottom.weightx = 1;
gbcPnlBottom.weighty = 1;
gbcPnlBottom.anchor = GridBagConstraints.NORTH;
gbPnlBottom.setConstraints( lbLblTime, gbcPnlBottom );
pnPnlBottom.add( lbLblTime );
tfTxtSeconds = new JTextField( );
gbcPnlBottom.gridx = 6;
gbcPnlBottom.gridy = 0;
gbcPnlBottom.gridwidth = 8;
gbcPnlBottom.gridheight = 1;
gbcPnlBottom.fill = GridBagConstraints.BOTH;
gbcPnlBottom.weightx = 1;
gbcPnlBottom.weighty = 0;
gbcPnlBottom.anchor = GridBagConstraints.WEST;
gbPnlBottom.setConstraints( tfTxtSeconds, gbcPnlBottom );
pnPnlBottom.add( tfTxtSeconds );
lbLblThreshhold = new JLabel( "Threshold:" );
gbcPnlBottom.gridx = 0;
gbcPnlBottom.gridy = 1;
gbcPnlBottom.gridwidth = 6;
gbcPnlBottom.gridheight = 1;
gbcPnlBottom.fill = GridBagConstraints.BOTH;
gbcPnlBottom.weightx = 1;
gbcPnlBottom.weighty = 1;
gbcPnlBottom.anchor = GridBagConstraints.NORTH;
gbPnlBottom.setConstraints( lbLblThreshhold, gbcPnlBottom );
pnPnlBottom.add( lbLblThreshhold );
tfTxtThreshold = new JTextField( );
gbcPnlBottom.gridx = 6;
gbcPnlBottom.gridy = 1;
gbcPnlBottom.gridwidth = 8;
gbcPnlBottom.gridheight = 1;
gbcPnlBottom.fill = GridBagConstraints.BOTH;
gbcPnlBottom.weightx = 1;
gbcPnlBottom.weighty = 0;
gbcPnlBottom.anchor = GridBagConstraints.NORTH;
gbPnlBottom.setConstraints( tfTxtThreshold, gbcPnlBottom );
pnPnlBottom.add( tfTxtThreshold );
gbcPnlMain.gridx = 0;
gbcPnlMain.gridy = 19;
gbcPnlMain.gridwidth = 20;
gbcPnlMain.gridheight = 2;
gbcPnlMain.fill = GridBagConstraints.BOTH;
gbcPnlMain.weightx = 1;
gbcPnlMain.weighty = 0;
gbcPnlMain.anchor = GridBagConstraints.NORTH;
gbPnlMain.setConstraints( pnPnlBottom, gbcPnlMain );
pnPnlMain.add( pnPnlBottom );
getContentPane().add(pnPnlMain);
}
public void addExitListener(ActionListener listen)
{
btBtnExit.addActionListener(listen);
}
public void addAddListener(ActionListener listen)
{
btBtnAdd.addActionListener(listen);
}
public void addRemoveListener(ActionListener listen)
{
btBtnRemove.addActionListener(listen);
}
public void addCholesterolListener(ActionListener listen) { cbChkCholesterol.addActionListener(listen);}
public JCheckBox getChkCholesterol() { return cbChkCholesterol;}
public DefaultTableModel getRightTableModel()
{
return this.tblRightModel;
}
public DefaultTableModel getLeftTableModel()
{
return this.tblLeftModel;
}
public JTable getLeftTable()
{
return this.tblLeft;
}
public JTable getRightTable()
{
return this.tblRight;
}
public void addRowToRightTable(Object[] newData)
{
tblRightModel.insertRow(tblRight.getRowCount(), newData);
}
public void populateLeftTable(String[][] data)
{
for(int i = 0; i < data.length; i++)
{
Object[] tempData = data[i];
tblLeftModel.insertRow(tblLeft.getRowCount(), tempData);
}
}
public void addColumnToRightTable(String code) throws ParseException {
tblRightModel.addColumn("Cholesterol",op.getAllPatientObservationValues(code));
}
}
public Object[] getAllPatientObservationValues(String code) throws ParseException {
System.out.println("In this method");
ArrayList<String> values = new ArrayList<>();
for (int i = 0; i < allPatients.size(); i++)
{
values.add(allPatients.get(i).getObservationValue(code));
}
return values.toArray();
}
更新：我看到当我创建我的表时，我有一个数据集的2D数组为一行7列，并认为这是问题，但当我增加它的大小，如8或留空，然后它仍然抛出错误
似乎你忘了将Operations对象op设置为inOP。
这个。
public GUIManager(Operations inOP)
{
setSize(1000, 650);
应该是这个
public GUIManager(Operations inOP)
{
op = inOP;
setSize(1000, 650);
我不知道你打算用inOP和op做什么(inOP的深层拷贝?)，但现在op是空的。这可能就是你的 NullPointerException 是来自，在行。tblRightModel.addColumn("Cholesterol",op.getAllPatientObservationValues(code));