Question

我想写入一个文件，但它似乎没有写进去，文件名是Grade output.txt ...

例如当我运行程序时，测验1：90的输入..这是它应该在停止运行后添加到文件上的Q1。

 'try {
            BufferedWriter out = new BufferedWriter(new FileWriter("Grade output.txt"));
                //for (int i = 0; i < 11; i++) {
                    out.write(Q1 + " ");



System.out.println(Q1);

                out.close();
            } catch (IOException e) {}

 import java.applet.Applet;
import java.awt.*;
 import java.awt.event.*;
  import java.io.BufferedWriter;
   import java.io.FileWriter;
      import java.io.IOException;

public class AICS_grade_applet extends Applet实现了ActionListener {

// Label titleLabel = new Label（“Grading System”，Label.CENTER）;

Label prelimsQ1Label = new Label("Quiz 1", Label.LEFT);
TextField prelimsQ1Field = new TextField(10);

Label prelimsQ2Label = new Label("Quiz 2", Label.LEFT);
TextField prelimsQ2Field = new TextField(10);

Label prelimsCSLabel = new Label("Quiz 3", Label.LEFT);
TextField prelimsCSField = new TextField(10);

Label prelimsEXLabel = new Label("Quiz 4", Label.LEFT);
TextField prelimsEXField = new TextField(10);

Label midtermQ1Label = new Label("Quiz 5", Label.LEFT);
TextField midtermQ1Field = new TextField(10);

Label midtermQ2Label = new Label("Quiz 6", Label.LEFT);
TextField midtermQ2Field = new TextField(10);

Label midtermCSLabel = new Label("Quiz 7", Label.LEFT);
TextField midtermCSField = new TextField(10);

Label midtermEXLabel = new Label("Quiz 8", Label.LEFT);
TextField midtermEXField = new TextField(10);

Label finalsQ1Label = new Label("Quiz 9", Label.LEFT);
TextField finalsQ1Field = new TextField(10);

Label finalsQ2Label = new Label("Quiz 10", Label.LEFT);
TextField finalsQ2Field = new TextField(10);

Label finalsCSLabel = new Label("Quiz 11", Label.LEFT);
TextField finalsCSField = new TextField(10);

Label finalsEXLabel = new Label("Quiz 12", Label.LEFT);
TextField finalsEXField = new TextField(10);

Button computeButton = new Button("  Compute  ");
Button clearButton = new Button("    Clear   ");

Label gradeLabel = new Label("Grade:   ", Label.RIGHT);
TextField gradeField = new TextField(10);

Label statusLabel = new Label("Status:   ", Label.RIGHT);
TextField statusField = new TextField("enter the data", 10);

public void init() { // begin init-------------------------------

    setBackground(Color.white);
    setForeground(Color.red);
//  add(titleLabel);

    add(prelimsQ1Label);
    add(prelimsQ1Field);
    prelimsQ1Field.setForeground(Color.red);

    add(prelimsQ2Label);
    add(prelimsQ2Field);
    prelimsQ2Field.setForeground(Color.red);

    add(prelimsCSLabel);
    add(prelimsCSField);
    prelimsCSField.setForeground(Color.red);

    add(prelimsEXLabel);
    add(prelimsEXField);
    prelimsEXField.setForeground(Color.red);

    add(midtermQ1Label);
    add(midtermQ1Field);
    midtermQ1Field.setForeground(Color.red);

    add(midtermQ2Label);
    add(midtermQ2Field);
    midtermQ2Field.setForeground(Color.red);

    add(midtermCSLabel);
    add(midtermCSField);
    midtermCSField.setForeground(Color.red);

    add(midtermEXLabel);
    add(midtermEXField);
    midtermEXField.setForeground(Color.red);

    add(finalsQ1Label);
    add(finalsQ1Field);
    finalsQ1Field.setForeground(Color.red);

    add(finalsQ2Label);
    add(finalsQ2Field);
    finalsQ2Field.setForeground(Color.red);

    add(finalsCSLabel);
    add(finalsCSField);
    finalsCSField.setForeground(Color.red);

    add(finalsEXLabel);
    add(finalsEXField);
    finalsEXField.setForeground(Color.red);

    add(computeButton);
    computeButton.addActionListener(this);
    add(clearButton);
    clearButton.addActionListener(this);

    add(gradeLabel);
    add(gradeField);
    gradeField.setForeground(Color.gray);

    add(statusLabel);
    add(statusField);
    statusField.setForeground(Color.blue);

} // end init

public void actionPerformed(ActionEvent yhan) {

    // declare object strings
    String strprelimsQ1 = new String(prelimsQ1Field.getText());
    String strprelimsQ2 = new String(prelimsQ2Field.getText());
    String strprelimsCS = new String(prelimsCSField.getText());
    String strprelimsEX = new String(prelimsEXField.getText());
    String strmidtermQ1 = new String(midtermQ1Field.getText());
    String strmidtermQ2 = new String(midtermQ2Field.getText());
    String strmidtermCS = new String(midtermCSField.getText());
    String strmidtermEX = new String(midtermEXField.getText());
    String strfinalsQ1 = new String(finalsQ1Field.getText());
    String strfinalsQ2 = new String(finalsQ2Field.getText());
    String strfinalsCS = new String(finalsCSField.getText());
    String strfinalsEX = new String(finalsEXField.getText());

    if (yhan.getSource() == computeButton)

    {
        if (strprelimsQ1.equals("")) {
            prelimsQ1Field.setText("0");
        }

        if (strprelimsQ2.equals("")) {
            prelimsQ2Field.setText("0");
        }

        if (strprelimsCS.equals("")) {
            prelimsCSField.setText("0");
        }

        if (strprelimsEX.equals("")) {
            prelimsEXField.setText("0");
        }

        if (strmidtermQ1.equals("")) {
            midtermQ1Field.setText("0");
        }

        if (strmidtermQ2.equals("")) {
            midtermQ2Field.setText("0");
        }

        if (strmidtermCS.equals("")) {
            midtermCSField.setText("0");
        }

        if (strmidtermEX.equals("")) {
            midtermEXField.setText("0");
        }

        if (strfinalsQ1.equals("")) {
            finalsQ1Field.setText("0");
        }

        if (strfinalsQ2.equals("")) {
            finalsQ2Field.setText("0");
        }

        if (strfinalsCS.equals("")) {
            finalsCSField.setText("0");
        }

        if (strfinalsEX.equals("")) {
            finalsEXField.setText("0");
        }

        // Converting input to values
        int Q1 = Integer.parseInt(prelimsQ1Field.getText());
        int Q2 = Integer.parseInt(prelimsQ2Field.getText());
        int Q3 = Integer.parseInt(prelimsQ2Field.getText());
        int Q4 = Integer.parseInt(prelimsEXField.getText());
        int Q5 = Integer.parseInt(midtermQ1Field.getText());
        int Q6 = Integer.parseInt(midtermQ2Field.getText());
        int Q7 = Integer.parseInt(midtermQ2Field.getText());
        int Q8 = Integer.parseInt(midtermEXField.getText());
        int Q9 = Integer.parseInt(finalsQ1Field.getText());
        int Q10 = Integer.parseInt(finalsQ2Field.getText());
        int Q11 = Integer.parseInt(finalsQ2Field.getText());
        int Q12 = Integer.parseInt(finalsEXField.getText());

        // Calculations
        double grade = (Q1 + Q2 + Q3 + Q4
                + Q5 + Q6 + Q7 + Q8 + Q9 + Q10+ Q11+ Q12) / 12;

        try {
            BufferedWriter out = new BufferedWriter(new FileWriter("Grade output.txt"));
                //for (int i = 0; i < 11; i++) {
                    out.write(Q1 + " ");



System.out.println(Q1);

                out.close();
            } catch (IOException e) {}

        // Output grade
        gradeField.setText("" + Math.round(grade));

        if (grade < 75) {
            statusField.setText("failed");
        } else {
            statusField.setText("Pass");
        }

        if (grade > 100) {
            statusField.setText("You may have invalid input");
        }
    } // end if computeButton

    if (yhan.getSource() == clearButton) {
        gradeField.setText("");
        prelimsQ1Field.setText("");
        prelimsQ2Field.setText("");
        prelimsCSField.setText("");
        prelimsEXField.setText("");
        midtermQ1Field.setText("");
        midtermQ2Field.setText("");
        midtermCSField.setText("");
        midtermEXField.setText("");
        finalsQ1Field.setText("");
        finalsQ2Field.setText("");
        finalsCSField.setText("");
        finalsEXField.setText("");
        statusField.setText("reenter the data");

    } // end if clearButton

} // end actionperformed

} //结束课程 “

Answer 1

除非签名，否则applet无法写入文件系统。您可以使用Java Web Start对applet进行签名或部署将applet重新开发为应用程序。

读：

无法写入文件，java swing

1 个答案: