我正在爲我的計算機科學課進行這個年級保留課程,而我還沒有開始工作的一件事就是保存/加載課程。正如我現在設置它,它會自動保存,當你退出時加載,當你啓動時加載,如果有文件加載。但是,我覺得我正在加載或保存不正確;有一個主要的JFrame包含所有的數據,並且這是保存的一個對象。當它被加載時,它會更容易向你展示。如何從文件正確加載JFrame?
If it looks like this when I close it::
然後it'll look like this when I start it up again:
此外, 「輸入學生」 按鈕,以及用於輸入對JTextField
的ActionListener
,停止工作當程序加載JFrame時。該計劃被分爲3類文件:
成績冊:
import javax.swing.*;
import java.awt.event.*;
import java.io.*;
public class GradeBook implements java.io.Serializable {
private static JFrame frame;
public static void main(String[] args) throws Exception{
try{
FileInputStream fis = new FileInputStream("t.tmp");
ObjectInputStream ois = new ObjectInputStream(fis);
frame = (JFrame) ois.readObject();
ois.close();
} catch(Throwable t) {
frame = new JFrame("Course Grades");
}
frame.addWindowListener(new closing());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new CourseGrade());
frame.pack();
frame.setVisible(true);
}
收盤:
private static class closing extends WindowAdapter {
public void windowClosing(WindowEvent e) {
try {
FileOutputStream fos = new FileOutputStream("t.tmp");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(frame);
oos.close();
} catch(Throwable t){System.out.println(t.getMessage());}
}
}
}
CourseGrade:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.FlowLayout;
import java.util.Random;
import javax.swing.table.*;
import java.io.*;
public class CourseGrade extends JPanel implements java.io.Serializable {
private JLabel entername;
private JTextField in;
private JTextArea list;
private JScrollPane scroll;
private String[] students = new String[1000];
private JButton enter;
private JButton[] studentbuttons = new JButton[1000];
private JButton[] delete=new JButton[1000];
private int numstudents;
private JFrame[] studentframes=new JFrame[1000];
private static JTable[] tables=new JTable[1000];
private static DefaultTableModel[] model=new DefaultTableModel[1000];
private static int[] numass=new int[1000];
public CourseGrade() {
String[][] data = {{"", "", "", ""}};
String[] headers = {"Assignment", "Date Assigned", "Score", "Percentage"};
for(int i=0; i<tables.length; i++){
model[i] = new DefaultTableModel(data, headers);
tables[i] = new JTable(model[i]){
public boolean isCellEditable(int rowIndex, int colIndex) {
return false;
}
};
}
numstudents=0;
in=new JTextField(13);
in.addActionListener(new enterListener());
list=new JTextArea();
scroll=new JScrollPane(list);
list.setEditable(false);
entername=new JLabel("Enter a student's name");
enter=new JButton("Enter Student");
enter.addActionListener(new enterListener());
setPreferredSize(new Dimension(260, 300));
setBackground(Color.green);
add(entername);
add(in);
add(enter);
add(scroll);
scroll.setPreferredSize(new Dimension(240, 200));
}
private class enterListener implements ActionListener {
public void actionPerformed(ActionEvent event) {
String x=in.getText();
String y="";
String z="";
in.setText("");
int a=numstudents+1;
if(x.length()>0) x=a+". " + x + "\n";
students[numstudents] = x;
if(x.length()>0)numstudents++;
for(int i=0; i<numstudents; i++){
x=students[i];
if(x.length()>13)x=x.substring(0,11)+"...\n";
y+=x;
}
studentbuttons[numstudents]=new JButton("Edit");
studentbuttons[numstudents].addActionListener(new grades());
delete[numstudents]=new JButton("Delete");
delete[numstudents].addActionListener(new del());
list.setText(y);
list.add(studentbuttons[numstudents]);
studentbuttons[numstudents].setBounds(100,(numstudents-1)*16,55,15);
list.add(delete[numstudents]);
delete[numstudents].setBounds(160,(numstudents-1)*16,70,15);
}
}
private class grades implements ActionListener {
public void actionPerformed(ActionEvent event) {
Object obj = event.getSource();
if(obj instanceof JButton){
JButton clicked = (JButton)obj;
int x=clicked.getY()/16;
String y=students[x];
for(int i=0; i<y.length(); i++){
String q=y.substring(i,i+1);
if(q.equals(" ")) {
y=y.substring(i+1);
i=y.length()+1;
}
}
studentframes[x]=new JFrame(y+"'s Grades");
studentframes[x].setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
try{studentframes[x].getContentPane().add(new GradePage(x, tables[x], numass[x]));}
catch(Exception e){}
studentframes[x].pack();
studentframes[x].setVisible(true);
}
}
}
private class del implements ActionListener {
public void actionPerformed(ActionEvent event) {
Object obj = event.getSource();
if(obj instanceof JButton){
JButton clicked = (JButton)obj;
int x=clicked.getY()/16;
String y="", z="";
studentbuttons[numstudents].setVisible(false);
delete[numstudents].setVisible(false);
numstudents--;
int q=3;
int w=0;
for(int i=x; i<=numstudents; i++){
if(i<10)q=1;
else if(i<100) q=2;
tables[i]=tables[i+1];
numass[i]=numass[i+1];
model[i]=model[i+1];
w=i+1;
try{if(!students[i+1].equals(null)){students[i]=w+students[i+1].substring(q);} else{students[i]=null;}}catch(Throwable t){}
}
for(int i=0; i<numstudents; i++){
y=students[i];
if(y.length()>13)y=y.substring(0,11)+"...\n";
z+=y;
}
list.setText(z);
}
}
}
public static void setTable(int numtable, JTable table){
tables[numtable]=table;
}
public static void newRow(int numtable){
model[numtable].addRow(new Object[]{"", "", "", ""});
}
public static void setNumEntries(int numtable, int num){
numass[numtable]=num;
}
}
第三類不應該有什麼關係有了這個,所以我現在不會發布它。
我意識到代碼可能寫得不好,但我只是在高中計算機科學的第二年,我們並沒有真正涉及到這一點。這個程序甚至不應該是一個圖形用戶界面,這是我第一次聽說過輸入或輸出流,所以我真的不知道它們。我現在意識到讓這些類實現java.io.Serializable可能是不必要的,但是當我試圖研究這個時,我遇到了一些人在考慮如何保存某些對象,因爲它們不會自然地實現它。非常抱歉,如果這是一個愚蠢的錯誤,並感謝您的時間。
我不會被執行'Serializable'用於閱讀這種類型的功能。相反,請看一系列其他不太脆弱的持久設置和屬性的方法。例如。在[這個答案](http://stackoverflow.com/a/7778332/418556)(它使用'屬性')。 Java提供了一種「麪包師」來堅持信息。 – 2012-03-04 20:21:15
如果用戶在序列化和反序列化之間更新他的Java,那麼很可能你的方法會失敗。 – 2012-03-04 20:32:00