好的，所以我对Java编程很陌生，而且我不太了解文件读/写的概念。我已经尝试查看关于文件的docs.oracle网页，但我发现它们并不是真的有用，考虑到我想做的事情有点不同。
我有这3个文件：CVolunteer，CDialog和TestDialog。 CVolunteer创建和反对可以自愿辅导学生的人。 CDialog管理志愿者的添加/编辑。 TestDialog显示志愿者的JList，并允许用户编辑，添加，删除或清除列表。我有3个班级完美地工作，并将在下面显示（对不起，他们很长！）。
这是我需要帮助的......我在主窗口添加了两个按钮，“保存”和“打开”。在任何时候，用户都应该能够保存当前的志愿者JList。单击“保存”时，将弹出一个JFileChooser窗口并询问用户是否存储了所有志愿者对象的文件名。当用户单击“打开”时，将弹出另一个JFileChooser窗口并询问用户他们要打开哪个文件。目前在主窗口中的志愿者将被删除，所选文件中的志愿者将取代他们的位置。我不确定是否需要使用序列化......
如果有人可以帮助解释如何完成此操作或帮助我编写代码来处理“保存”/“打开”事件，我将非常感激！在此先感谢:)
我相信唯一需要更改的文件是TestDialog，我包含了其他文件以防有人想要尝试运行它
***对不起，如果有任何缩进错误，我必须在此对话框中手动完成 CVolunteer.java
public class CVolunteer {
int volNum;
String name;
int sub, volDays, trans;
public CVolunteer(int vNum, String vName, int subj, int days, int needTrans){
volNum = vNum;
name = vName;
sub = subj;
volDays = days;
trans = needTrans;
}
private String subjectToString()
{
switch (sub){
case 0:
return "Math";
case 1:
return "Science";
case 2:
return "English";
case 3:
return "History";
}
return " ";
}
private String volDaysToString()
{
String str = "";
str +=((volDays&1)!=0)?"M":"-";
str +=((volDays&2)!=0)?"T":"-";
str +=((volDays&4)!=0)?"W":"-";
str +=((volDays&8)!=0)?"R":"-";
return str;
}
private String transToString()
{
switch(trans)
{
case 0:
return "Yes";
case 1:
return "No";
}
return " ";
}
public String getVolunteerLine()
{
return String.format("%05d %-30s%-30s%-30s%s",
volNum, name, subjectToString(), volDaysToString(), transToString());
}
}
CDialog.java
import java.awt.Container;
import java.awt.event.*;
import javax.swing.*;
public class CDialog extends JDialog implements ActionListener
{
private JLabel label1;
private JLabel lNum;
private JLabel label2;
private JTextField tfName;
private JLabel label3;
private ButtonGroup subGroup;
private JRadioButton rbMath;
private JRadioButton rbScience;
private JRadioButton rbEnglish;
private JRadioButton rbHistory;
private JLabel label4;
private JCheckBox cbMonday;
private JCheckBox cbTuesday;
private JCheckBox cbWednesday;
private JCheckBox cbThursday;
private JLabel label5;
private ButtonGroup transGroup;
private JRadioButton rbYes;
private JRadioButton rbNo;
private JButton okButton = null;
private JButton cancelButton = null;
private boolean cancelled = true;
public boolean isCancelled() {return cancelled;}
private CVolunteer answer;
public CVolunteer getAnswer() {return answer;}
public CDialog(JFrame owner, String title, CVolunteer vol)
{
super(owner, title, true);
Container c = getContentPane();
c.setLayout(null);
label1 = new JLabel ("Volunteer Number:");
label1.setSize(140,20);
label1.setLocation(40,40);
c.add(label1);
lNum = new JLabel(String.format("%05d", vol.volNum));
lNum.setSize(40,20);
lNum.setLocation(150,40);
c.add(lNum);
label2 = new JLabel ("Volunteer Name: ");
label2.setSize(100,20);
label2.setLocation(40,90);
c.add(label2);
tfName = new JTextField(vol.name);
tfName.setSize(120,20);
tfName.setLocation(140,90);
c.add(tfName);
int x,y;
int w,h;
x=4;
y=150;
w=180;
h=20;
label3 = new JLabel("Subject: ");
label3.setSize(85,13);
label3.setLocation(x,y);
c.add(label3);
rbMath = new JRadioButton("Math", vol.sub==0);
rbMath.setSize(w,h);
rbMath.setLocation(x+16,y+30);
c.add(rbMath);
rbScience = new JRadioButton("Science", vol.sub==1);
rbScience.setSize(w,h);
rbScience.setLocation(x+16,y+66);
c.add(rbScience);
rbEnglish = new JRadioButton("English", vol.sub==2);
rbEnglish.setSize(w,h);
rbEnglish.setLocation(x+16,y+102);
c.add(rbEnglish);
rbHistory = new JRadioButton("History", vol.sub==3);
rbHistory.setSize(w,h);
rbHistory.setLocation(x+16,y+138);
c.add(rbHistory);
subGroup = new ButtonGroup();
subGroup.add(rbMath);
subGroup.add(rbScience);
subGroup.add(rbEnglish);
subGroup.add(rbHistory);
x=220;
y=150;
w=120;
h=20;
label4 = new JLabel("Days Available: ");
label4.setSize(w,h);
label4.setLocation(x,y);
c.add(label4);
cbMonday = new JCheckBox("Monday (M)", (vol.volDays&1)!=0);
cbMonday.setSize(w,h);
cbMonday.setLocation(x+6,y+30);
c.add(cbMonday);
cbTuesday = new JCheckBox("Tuesday (T)", (vol.volDays&2)!=0);
cbTuesday.setSize(w,h);
cbTuesday.setLocation(x+6,y+66);
c.add(cbTuesday);
cbWednesday = new JCheckBox("Wednesday (W)", (vol.volDays&4)!=0);
cbWednesday.setSize(w,h);
cbWednesday.setLocation(x+6,y+102);
c.add(cbWednesday);
cbThursday = new JCheckBox("Thursday (R)", (vol.volDays&8)!=0);
cbThursday.setSize(w,h);
cbThursday.setLocation(x+6,y+138);
c.add(cbThursday);
x=480;
y=150;
w=180;
h=20;
label5 = new JLabel("Need Transport? :");
label5.setSize(150,13);
label5.setLocation(x,y);
c.add(label5);
rbYes = new JRadioButton("Yes", vol.trans==0);
rbYes.setSize(w,h);
rbYes.setLocation(x+12,y+30);
c.add(rbYes);
rbNo = new JRadioButton("No", vol.trans==1);
rbNo.setSize(w,h);
rbNo.setLocation(x+12,y+66);
c.add(rbNo);
transGroup = new ButtonGroup();
transGroup.add(rbYes);
transGroup.add(rbNo);
cancelButton = new JButton("Cancel");
cancelButton.addActionListener(this);
cancelButton.setSize(100,50);
cancelButton.setLocation(116,380);
c.add(cancelButton);
okButton = new JButton("OK");
okButton.addActionListener(this);
okButton.setSize(100,50);
okButton.setLocation(400,380);
c.add(okButton);
setSize(700,480);
setLocationRelativeTo(owner);
setVisible(true);
}
public void actionPerformed(ActionEvent e)
{
if (e.getSource()==okButton) {
int num=Integer.parseInt(lNum.getText());
String name=tfName.getText();
int subj=-1;
if (rbMath.isSelected()) subj = 0;
if (rbScience.isSelected()) subj = 1;
if (rbEnglish.isSelected()) subj = 2;
if (rbHistory.isSelected()) subj = 3;
int days=0;
if (cbMonday.isSelected()) days |= 1;
if (cbTuesday.isSelected()) days |= 2;
if (cbWednesday.isSelected()) days |= 4;
if (cbThursday.isSelected()) days |= 8;
int tran=0;
if (rbYes.isSelected()) tran = 0;
if (rbNo.isSelected()) tran = 1;
answer=new CVolunteer(num, name, subj, days, tran);
cancelled = false;
setVisible(false);
}
else if(e.getSource()==cancelButton) {
cancelled = true;
setVisible(false);
}
}
}
TestDialog.java
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import java.io.*;
import java.util.ArrayList;
public class TestDialog extends JFrame implements ActionListener
{
JLabel myLabel1 = null;
JLabel myLabel2 = null;
JLabel myLabel3 = null;
JLabel myLabel4 = null;
JLabel myLabel5 = null;
JLabel myLabel6 = null;
File fileName = new File("Volunteers.txt");
ArrayList<CVolunteer> volArray;
private DefaultListModel volunteers;
JList volList;
JScrollPane scrollPane = null;
JButton bAdd = null;
JButton bEdit = null;
JButton bRemove = null;
JButton bClear = null;
JButton bSave = null;
JButton bOpen = null;
int volNumb;
public TestDialog()
{
super("Volunteer Info");
Container c = getContentPane();
c.setLayout(null);
myLabel1 = new JLabel("Vol Number");
myLabel1.setSize(200,50);
myLabel1.setLocation(100,10);
c.add(myLabel1);
myLabel2 = new JLabel("Vol Name");
myLabel2.setSize( 200, 50 );
myLabel2.setLocation( 200, 10 );
c.add(myLabel2);
myLabel3 = new JLabel("Subject");
myLabel3.setSize( 200, 50 );
myLabel3.setLocation( 310, 10);
c.add(myLabel3);
myLabel4 = new JLabel("Vol Days");
myLabel4.setSize( 200, 50 );
myLabel4.setLocation( 400, 10 );
c.add(myLabel4);
myLabel5 = new JLabel("Transport");
myLabel5.setSize( 200, 50 );
myLabel5.setLocation( 500, 10 );
c.add(myLabel5);
volArray = new ArrayList<CVolunteer>();
volunteers = new DefaultListModel();
volList = new JList(volunteers);
volList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
scrollPane = new JScrollPane(volList);
scrollPane.setSize(500,300);
scrollPane.setLocation(100,50);
c.add(scrollPane);
bAdd = new JButton("Add");
bAdd.setSize( 100, 50 );
bAdd.setLocation( 20, 400 );
bAdd.addActionListener(this);
c.add(bAdd);
bEdit = new JButton("Edit");
bEdit.setSize( 100, 50 );
bEdit.setLocation( 150, 400 );
bEdit.addActionListener(this);
c.add(bEdit);
bRemove = new JButton("Remove");
bRemove.setSize( 100, 50 );
bRemove.setLocation( 280, 400 );
bRemove.addActionListener(this);
c.add(bRemove);
bClear = new JButton("Clear");
bClear.setSize( 100, 50 );
bClear.setLocation( 410, 400 );
bClear.addActionListener(this);
c.add(bClear);
bSave = new JButton("Save");
bSave.setSize( 100, 50 );
bSave.setLocation( 540, 400 );
bSave.addActionListener(this);
c.add(bSave);
bOpen = new JButton("Open");
bOpen.setSize( 100, 50 );
bOpen.setLocation( 670, 400 );
bOpen.addActionListener(this);
c.add(bOpen);
setSize( 800, 600 );
setLocation( 100, 100 );
setVisible(true);
volNumb = 0;
}
public void actionPerformed(ActionEvent e) {
if(e.getSource()==bAdd) {
volNumb++;
CVolunteer defaultVol = new CVolunteer(volNumb, "", 1, 0, 0);
CDialog dialogWnd = new CDialog(this, "Add a Volunteer", defaultVol);
if (!dialogWnd.isCancelled()) {
volArray.add(dialogWnd.getAnswer());
volunteers.addElement(dialogWnd.getAnswer().getVolunteerLine());
volList.setSelectedIndex(volunteers.size()-1);
volList.ensureIndexIsVisible(volunteers.size()-1);
}
}
else if(e.getSource()==bEdit) {
int index=volList.getSelectedIndex();
if (index>=0) {
CDialog dialogWnd = new CDialog (this, "Edit a Volunteer", volArray.get(index));
if (!dialogWnd.isCancelled()) {
volArray.set(index, dialogWnd.getAnswer());
volunteers.set(index, dialogWnd.getAnswer().getVolunteerLine());
}
}
}
else if(e.getSource()==bRemove) {
int index=volList.getSelectedIndex();
if (index>=0) {
volArray.remove(index);
volunteers.remove(index);
if (volunteers.size()>0) {
if (index==volunteers.size()) {
index--;
}
volList.setSelectedIndex(index);
volList.ensureIndexIsVisible(index);
}
}
}
else if(e.getSource()==bClear) {
volArray.clear();
volunteers.clear();
}
else if (e.getSource()==bSave)
{
//my sorry attempt at writing a file.. ignore this!
try {
FileWriter fw = new FileWriter(fileName);
Writer output = new BufferedWriter(fw);
int size = volArray.size();
for (int i = 0; i<size; i++)
{
output.write(volArray.get(i).getVolunteerLine() + "\n");
}
output.close();
}
catch (Exception e1) {
// TODO Auto-generated catch block
}
final JFileChooser fc = new JFileChooser();
}
else if (e.getSource()==bOpen)
{
}
}
public static void main(String[] args) {
TestDialog mainWnd = new TestDialog();
}
}
编辑：
这是我的“保存”按钮的一些尝试代码....我仍然不知道这是否在正确的轨道上！它似乎没有做任何事情
else if (e.getSource()==bSave)
{
try
{
FileOutputStream fileOut = new FileOutputStream("???");
ObjectOutputStream out = new ObjectOutputStream(fileOut);
for(int i=0; i<volArray.size(); i++)
{
out.writeObject(volArray.get(i).getVolunteerLine());
}
out.close();
fileOut.close();
} catch (Exception e1) {
// TODO Auto-generated catch block
}
final JFileChooser fc = new JFileChooser();
}
答案 0 :(得分：0)
您必须使用您定义的特定格式在文件中写入： 在志愿者课程中添加序列化方法，然后您可以迭代它们并序列化它们。 String serialize（）会将所有成员编码为字符串，然后您可以在读取时重新构建（在打开时）。
示例可以是逗号分隔列表：member1 = xxx，member2 = xxx，... 或者xml或json更容易：）
在阅读时，相反，解析文件的内容并建立志愿者！
编辑：
Saving:
Open a file in write mode
write all your n volunteers
at this point you should have n lines in your file
close the file
Reading:
Open your file in reading mode
Read it line by line
For each line
split over ','
build your volunteer
add it to volArray
close your file
对你有意义吗？通过简单的谷歌搜索
，每个步骤都是微不足道的编辑： 最终的JFileChooser fc = new JFileChooser（）;
if (returnVal == JFileChooser.APPROVE_OPTION) {
File file = fc.getSelectedFile();
//This is where a real application would open the file.
log.append("Opening: " + file.getName() + "." + newline);
// Here you can open the file and write to it
//
} else {
log.append("Open command cancelled by user." + newline);
}
您可以在打开时执行相同操作，选择文件然后从中读取