java - java中如何解决这个 'cannot find symbol'

Question

我是一名一年级学生，对 java 编程非常陌生，我真的希望你们能够忍受我的问题。我有以下代码，它在 Eclipse 上完美运行，但无法在 Linux 的终端中运行。代码如下:

Person.java

package src2;

public class Person implements Runnable {

protected Bathroom bathroom;
private boolean isMale;

// Minimum time to idle
private int minIdleTime = 1000;

// Maximum time to idle
private int maxIdleTime = 1300;

// Minimum time to spend in a stall
private int minInStallTime = 1500;

// Maximum time to spend in a stall
private int maxInStallTime = 2000;
private long startWaitTime;

public Person(Bathroom bathroom, boolean isMale) {
    this.bathroom = bathroom;
    this.isMale = isMale;
}

/**
 * Determines how long a person has been waiting in the queue.
 *
 * @return The length a person has been waiting.
 */
public long getWaitingTime() {
    return System.currentTimeMillis() - startWaitTime;
}

/**
 * Returns gender of person.
 *
 * @return true indicates male, false indicates female.
 */
public boolean isMale() {
    return isMale;
}

/**
 * The run method - called when thread starts.
 */
public void run() {
    // Constantly loop
    // Wait random amount of time before queuing to use the bathroom (±Æ¶?)
    try {
        Thread.sleep((int) (minIdleTime + (maxIdleTime - minIdleTime)
                * Math.random()));
    }
    catch (InterruptedException e) {
        e.printStackTrace();
    }
    // Queue up for the Bathroom.
    try {
        // Remember the time person started to queue.
        startWaitTime = System.currentTimeMillis();

        // Queue in the bathroom - it will sleep until woken up.
        bathroom.enqueuePerson(this);

    }
    catch (InterruptedException e1) {
        e1.printStackTrace();
    }
    // Now 'bathroom' has woken person up, meaning they are in a stall. (Sb¬~Yþ)
    try {

        // Do something for a random amount of time to represent
        // 'using' the bathroom
        Thread.sleep((int) (minInStallTime + (maxInStallTime - minInStallTime)
                * Math.random()));
    }
    catch (InterruptedException e) {
        e.printStackTrace();
    }
    // Finished using the bathroom, so inform it.
    try {
        bathroom.offerStall(this);
    } catch (InterruptedException e2) {
        // TODO Auto-generated catch block
        e2.printStackTrace();
    }

    // Loop to begin cycle again.
    while (true) {
        // Wait random amount of time before queuing to use the bathroom
        try {
            Thread.sleep((int) (minIdleTime + (maxIdleTime - minIdleTime)
                    * Math.random()));
        }
        catch (InterruptedException e) {
            e.printStackTrace();
        }
        // Queue up for the Bathroom.
        try {
            // Remember the time person started to queue.
            startWaitTime = System.currentTimeMillis();
            // Queue in the bathroom - it will sleep until woken up.
            bathroom.enqueuePerson(this);
        }
        catch (InterruptedException e1) {
            e1.printStackTrace();
        }
        // Now 'bathroom' has woken person up, meaning they are in a
        // stall.
        try {
            // Do something for a random amount of time to represent
            // 'using' the bathroom
            Thread.sleep((int) (minInStallTime + (maxInStallTime - minInStallTime)
                    * Math.random()));
        }
        catch (InterruptedException e) {
            e.printStackTrace();
        }
        // Finished using the bathroom, so inform it.
        try {
            bathroom.offerStall(this);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        // Loop to begin cycle again.
    }
}
}

浴室.java

package src2;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.Random;

public class Bathroom {

private LinkedList bathroomQueue = new LinkedList();
private LinkedList stallOccupants = new LinkedList();

private int noOfStalls = 5;

// Used as measurements
private int totalFemales = 0;
private long femaleQueueTimeTotal = 0;
private int totalMales = 0;
private long maleQueueTimeTotal = 0;
private int MinUseBathroomTime = 1500;
private int MaxUseBathroomTime = 2000;
private int exitMales = 0;
private int exitFemales = 0;
Person in = null; //the person do not know the sex yet.

/*
  * The JFrame to update in order to show measurements. Not really a very OO
  * way of doings things (e.g., forcing unrelated classes to rely on each
  * other), but works fine for demonstration purposes.
  */
private RunBathroom windowThread;

public Bathroom(RunBathroom windowThread) {
    this.windowThread = windowThread;
}

/**
 * Enters a {@link Person} Person into the queue for the bathroom
 *
 * @param person The {@link Person} Person to enter into the queue
 * @throws InterruptedException
 */
public void enqueuePerson(Person person) throws InterruptedException {
    Person nextInStall;
    // Add person to the queue and then check to see if they're next in line.
    // Lock the object to prevent a context switch allowing someone else
    // enter the queue first
    synchronized (this) {
        bathroomQueue.add(person);
        nextInStall = offerStall(null);
    }
    // If not next in line, put person to sleep
    if (person != nextInStall) {
        synchronized (person) {
            person.wait();
        }
    }
}

/**
 * Method the check who is next to enter bathroom
 *
 * @param remove Person to remove from a stall (can be null)
 * @return The Person
 * @throws InterruptedException 
 */
public synchronized Person offerStall(Person remove) throws InterruptedException {

    Person occupiersGender = (Person) stallOccupants.peek(); //the person in the bathroom.
    Person nextPerson = (Person) bathroomQueue.peek(); //the person in the bathroom queue.
    boolean maleInControl = false; // = false (is a male); 

    // If given, remove the person from a stall
    if (remove != null) {
        removePerson(remove, stallOccupants);
    }
    Person in = null; //the person do not know the sex yet.
    // If no-one is queuing, or if the stalls are full, return null.
    if (bathroomQueue.size() == 0 || stallOccupants.size() >= noOfStalls) {
        in = null;
    } else {
        // Otherwise find next the next person to enter bathroom
/*        Person occupiersGender = (Person) stallOccupants.peek(); //the person in the bathroom.
        Person nextPerson = (Person) bathroomQueue.peek(); //the person in the bathroom queue.
        boolean maleInControl; // = false (is a male);     */

        // If someone is in the bathroom, find out which sex
        if (occupiersGender != null) {
            maleInControl = occupiersGender.isMale(); // stallOc
        }
        // If nobody is in bathroom, then give control to whoever is next in queue
        else {
            maleInControl = nextPerson.isMale();
        }
        // If someone exists in the queue
        if (nextPerson != null) {
            // If the next person is male, and males are in control of the bathroom, or the bathroom is empty
            if (nextPerson.isMale()
                    && (maleInControl || stallOccupants.size() == 0)) {
                in = nextPerson;
            }
            // Otherwise, if next person is female, and females are in control, or the bathroom is empty
            else if (!nextPerson.isMale()
                    && (!maleInControl || stallOccupants.size() == 0)) {
                maleInControl = false; //this is a female.
                in = nextPerson;
            }
            // Otherwise, the next person in the queue cannot yet enter.
            else {
                in = null;
            }
        }
    }

    // If a person was chosen to enter bathroom
    if (in != null) {
        Random r=new Random();
        int i = r.nextInt(5);
        // Remove them from the queue, and update measurements/window
        if (in.isMale()) {
            while(in.isMale()){
                for(int j = 0; j <= i; j++){
                    removePerson(in, bathroomQueue);
                    maleQueueTimeTotal += in.getWaitingTime();
                    totalMales++;
                    Thread.sleep((int) (MinUseBathroomTime + (MaxUseBathroomTime - MinUseBathroomTime) 
                            *Math.random()));
                    windowThread.update(in.isMale(),totalMales, exitMales);
                }
                for(int j = 0; j<=i; j++){
                     Thread.sleep((int) (MinUseBathroomTime + (MaxUseBathroomTime - MinUseBathroomTime) 
                            *Math.random()));
                     exitMales++; 
                     windowThread.update(in.isMale(), totalMales, exitMales);
                }
                in = (Person) bathroomQueue.getFirst();

            }
        } else {
            while(!in.isMale()){
                for(int j = 0; j <= i; j++){
                    removePerson(in, bathroomQueue);
                    femaleQueueTimeTotal += in.getWaitingTime();
                    totalFemales++;
                    Thread.sleep((int) (MinUseBathroomTime + (MaxUseBathroomTime - MinUseBathroomTime) 
                            *Math.random()));
                    windowThread.update(in.isMale(), totalFemales, exitFemales);
                }
                for(int j = 0; j<=i; j++){
                     Thread.sleep((int) (MinUseBathroomTime + (MaxUseBathroomTime - MinUseBathroomTime) 
                            *Math.random()));
                     exitFemales++; 
                     windowThread.update(in.isMale(),totalFemales, exitFemales);
                }
                in = (Person) bathroomQueue.getFirst();
            }
        }
        // Add the person to a stall
        stallOccupants.add(in);
        // Notify the person so as to wake them up
        synchronized (in) {
            in.notify();
        }
    }
    // Return the person
    return in;
}
/**
 * Removes a person from a list
 *
 * @param person Person to remove
 * @param list   Queue/list to remove from
 */
private void removePerson(Person person, LinkedList list) {
    // Iterate through the list and remove the person if found
    Iterator i = list.iterator();
    while (i.hasNext()) {
        if (i.next() == person) {
            i.remove();
        }
    }
}
}

RunBathroom.java

package src2;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;

/**
 * Application demonstrating a fair solution to the "Unisex Bathroom" problem.
 * Creates the GUI and upon clicking "Start", initialises the {@link Bathroom} and populates
 * the queue with females and males.
 * <p/>
 * A random arrival pattern is used.
public class RunBathroom extends JFrame implements Runnable, ActionListener {
private JLabel totalMales, totalFemales, totalUsers, malestate, femalestate,     exitmale, exitfemale, emptymale, emptyfemale;
private JButton startItem = new JButton("Start");
private JButton quit = new JButton("Quit");
private Bathroom bathroom;

// Boolean representing the gender currently occupying the bathroom; true indicates male, false indicates female.
private boolean isMale = true;

public static void main(String[] args) {
    new Thread(new RunBathroom()).start();
}

/**
 * Constructor which sets up all the necessary components of the GUI.
 */
public RunBathroom() {

    super("Unisex Toilet Problem");
    setSize(700, 300);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setLocationRelativeTo(null);
    JPanel bottomPanel = new JPanel();

    // Add start button
    startItem.setText("Start");
    startItem.addActionListener(this);
    bottomPanel.add(startItem);
    startItem.setEnabled(false);

    // Add quit button
    quit.addActionListener(this);
    bottomPanel.add(quit);
    JPanel mainPanel = new JPanel(new GridLayout(2, 1));
    JPanel topPanel = new JPanel(new GridLayout(5, 2));
    JPanel topPanel2 = new JPanel (new GridLayout(3, 2));
    totalMales = new JLabel("0");
    totalMales.setHorizontalAlignment(SwingConstants.CENTER);
    totalFemales = new JLabel("0");
    totalFemales.setHorizontalAlignment(SwingConstants.CENTER);
    totalUsers = new JLabel("0");
    totalUsers.setHorizontalAlignment(SwingConstants.CENTER);
    malestate = new JLabel ("0");
    malestate.setHorizontalAlignment(SwingConstants.CENTER);
    femalestate = new JLabel ("0");
    femalestate.setHorizontalAlignment(SwingConstants.CENTER);
    exitmale = new JLabel ("0");
    exitmale.setHorizontalAlignment (SwingConstants.CENTER);
    exitfemale = new JLabel ("0");
    exitfemale.setHorizontalAlignment(SwingConstants.CENTER);
    emptymale = new JLabel ("0");
    emptymale.setHorizontalAlignment(SwingConstants.CENTER);
    emptyfemale = new JLabel ("0");
    emptyfemale.setHorizontalAlignment(SwingConstants.CENTER);

    // Add labels
    topPanel.add(new JLabel("Total males: "));
    topPanel.add(totalMales);
    topPanel.add(new JLabel("Total females: "));
    topPanel.add(totalFemales);
    topPanel.add(new JLabel ("Male state: "));
    topPanel.add(malestate);
    topPanel.add(new JLabel ("Female state: "));
    topPanel.add(femalestate);
    topPanel.add(new JLabel("Number of exit male: "));
    topPanel.add(exitmale);
    topPanel.add(new JLabel("Number of exit female: "));
    topPanel.add(exitfemale);
    topPanel.add(new JLabel(" "));
    topPanel.add(emptymale);
    topPanel.add(new JLabel(" "));
    topPanel.add(emptyfemale);
    topPanel.add(new JLabel("Total Number of persons: "));
    topPanel.add(totalUsers);

    mainPanel.add(topPanel);
    mainPanel.add(topPanel2);
    Container contentPane = getContentPane();
    contentPane.add(mainPanel, "Center");
    contentPane.add(bottomPanel, "South");
    startItem.setEnabled(true);
}

/**
 * When the thread starts, display the GUI.
 */
public void run() {
    setVisible(true);
}

/**
 * Exits on close of window
 *
 * @param e Windowevent (close)
 */
public void windowClosed(WindowEvent e) {
    System.exit(0);
}

/**
 * Listens for mouse-presses on menu items.
 *
 * @param evt The ActionEvent performed
 */
public void actionPerformed(ActionEvent evt) {

    Object source = evt.getSource();

    // If Quit is clicked, exit program.
    if (source == quit) {
        System.exit(0);
    }
    // If Start is clicked, create a bathroom and add male and female
    // persons to it.
    else if (source == startItem) {
        startItem.setEnabled(false);
        bathroom = new Bathroom(this);
        for (int i = 0; i < 10; i++) {
            new Thread(new Person(bathroom, !isMale)).start();
            new Thread(new Person(bathroom, isMale)).start();
        }
    }
}

/**
 * Updates the labels on the GUI
 *
 * @param isMale      Sex referring to the label to update
 * @param averageTime The average time that gender has had to wait
 * @param totalOfSex  The total number of that gender which has used to bathroom
 */
public void update(boolean isMale, int totalOfSex, int exitOfpeople) {
    if (isMale) {
        totalMales.setText(Integer.toString(totalOfSex));
        exitmale.setText(Integer.toString(exitOfpeople));
        malestate.setText("GOING");
        femalestate.setText("WAITING");
        if (totalOfSex == exitOfpeople){
            emptymale.setText("Everyone can go!");
            emptyfemale.setText(" ");
        }else{
            emptymale.setText("Only for Male");
            emptyfemale.setText(" ");
        }
    } else {
        totalFemales.setText(Integer.toString(totalOfSex));
        exitfemale.setText(Integer.toString(exitOfpeople));
        femalestate.setText("GOING");
        malestate.setText("WAITING");
        if (totalOfSex == exitOfpeople){
            emptyfemale.setText("Everyone can go!");
            emptymale.setText(" ");
        }else{
            emptyfemale.setText("Only for Female");
            emptymale.setText(" ");
        }
    }
    totalFemales.getText();
    totalUsers.setText(Integer.toString(Integer.parseInt((totalFemales.getText()))
            + Integer.parseInt((totalMales.getText()))));
}

}

仍有 17 个错误提示找不到符号。我已经尽力去理解，但还是无法理解。没人能帮忙吗？ :(显示的错误如下:

Bathroom.java:30:错误:找不到符号
人= null;//这个人还不知道性别。
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:37:错误:找不到符号
私有(private)运行浴室窗口线程；
^
符号:类 RunBathroom
地点:类(class)浴室
Bathroom.java:39:错误:找不到符号
公共(public)浴室(RunBathroom windowThread){
^
符号:类 RunBathroom
地点:类(class)浴室
Bathroom.java:49:错误:找不到符号
公共(public)无效 enqueuePerson(Person person) 抛出 InterruptedException {
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:73:错误:找不到符号
公共(public)同步的人offerStall(人删除)抛出InterruptedException {
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:73:错误:找不到符号
公共(public)同步的人offerStall(人删除)抛出InterruptedException {
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:180: 错误:找不到符号
私有(private)无效removePerson(人，LinkedList列表){
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:50:错误:找不到符号
下一个进入失速的人；
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:75:错误:找不到符号
人员占用者性别=(人员)stallOccupants.peek();//浴室里的人。
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:75:错误:找不到符号
人员占用者性别=(人员)stallOccupants.peek();//浴室里的人。
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:76:错误:找不到符号
人 nextPerson = (Person) BathroomQueue.peek();//洗手间排队的人。
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:76:错误:找不到符号
人 nextPerson = (Person) BathroomQueue.peek();//洗手间排队的人。
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:83:错误:找不到符号
人= null;//这个人还不知道性别。
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:142:错误:找不到符号
in = (Person) BathroomQueue.getFirst();
^
符号:类 Person
地点:类(class)浴室
Bathroom.java:161:错误:找不到符号
in = (Person) BathroomQueue.getFirst();
^
符号:类 Person
地点:类(class)浴室
15 个错误


Answer 1

import Person.java;
import RunBathroom.java;

看到带有 .java 后缀的包名真是太不寻常了。请检查您的导入语句和 Person 类的包名称。