用Java写入Binary

| 我正在制作一个使用两个数组列表的程序。我已经研究了如何将对象写入二进制文件，并且尝试实现它，但是它永远无法正常工作。我需要能够运行程序来创建文件，然后在要保存时写入文件。下次加载程序时，它需要能够重新读取数组列表。我已经在我存储的两个对象中实现了Serializable。 
import java.util.ArrayList;

import java.util.Scanner;

import java.io.*;

//Add person functionality next
public class main {
    ArrayList<Person> people = new ArrayList<Person>();
    ArrayList<Date> dates = new ArrayList<Date>();

    //Possibly add a checkExistence Function somewhere
    //Otherwise self explanatory
    public boolean newPerson(){
        Scanner kbd = new Scanner(System.in);

        String input = \"\";
        boolean nameIsCorrect = false;
        boolean typeIsCorrect = false;
        do{
            boolean nameContinue = false;
            while(!nameContinue){
                System.out.println(\"What is the name?\");
                input = kbd.nextLine();
                nameContinue = yesOrNo();
                if(nameContinue){
                    nameContinue = checkForExistence(input);
                    if(!nameContinue){
                        System.out.println(\"Name already exists, try again\");
                    }
                }
            }
            String[] tokens = input.split(\" \");
            if(tokens.length == 1){
                String name = tokens[0];
                String type = \"\";
                do{
                    System.out.println(\"What type? F (Family) P (Punch) S (Season)\");
                    input = kbd.nextLine();
                    if(input.equalsIgnoreCase(\"f\")){
                        type = \"f\";
                        typeIsCorrect = true;
                        nameIsCorrect = true;
                    }
                    else if(input.equalsIgnoreCase(\"s\")){
                        type = \"s\";
                        typeIsCorrect = true;
                        nameIsCorrect = true;
                    }
                    else if(input.equalsIgnoreCase(\"p\")){
                        type = \"p\";
                        typeIsCorrect = true;
                        nameIsCorrect = true;
                    }
                    else{
                        System.out.println(\"Invalid, try again\");
                    }
                } while(!typeIsCorrect);
                Person np = new Person(name, type);
                people.add(np);
                System.out.println(np.getName() + \" added!\");
            }
            else{
                System.out.println(\"Not correct format let\'s try again\");
            }
        } while(!nameIsCorrect);
        return true;
    }//End of newPerson function

    //Cycles through and prints a roster
    public boolean printPeopleList(){
        for(int i = 0; i < people.size(); i++){
            System.out.println(people.get(i).getName());
        }
        return true;
    }

    //Testing for valid input
    public boolean testDateValidity(String input, int which){
        if(which == 1){
            String[] dates = new String[21];
            int count = 0;
            for(int i = 1; i <= 12; i++){
                if(i < 10){
                    dates[count] = \"0\" + Integer.toString(i);
                    count++;
                }
                dates[count] = Integer.toString(i);
                count++;
            }

            for(int j = 0; j < dates.length; j++){
                if(input.equalsIgnoreCase(dates[j])){
                    return true;
                }
            }
        }
        else if(which == 2){
            String[] dates = new String[40];
            int count = 0;
            for(int i = 1; i <= 31; i++){
                if(i < 10){
                    dates[count] = \"0\" + Integer.toString(i);
                    count++;
                }
                dates[count] = Integer.toString(i);
                count++;
            }

            for(int j = 0; j < dates.length; j++){
                if(input.equalsIgnoreCase(dates[j])){
                    return true;
                }
            }
        }
        else{
            return false;
        }

        return false;
    }

    //Cycles through and prints all dates and their attendance
    public boolean printListOfDates(){
        System.out.println(\"Date\\tPeople\");
        for(int i = 0; i < dates.size(); i++){
            System.out.println(dates.get(i).toString());
        }
        return true;
    }

    public boolean printCurrentPeople(int day){
        dates.get(day).printList();
        return true;
    }

    //Returns the day position from the ArrayList
    public int findDayPosition(String month, String day){
        for(int i = 0; i < dates.size(); i++){
            if(month.equalsIgnoreCase(dates.get(i).getMonth()) && day.equalsIgnoreCase(dates.get(i).getDay())){
                return i;
            }
        }

        return -1;
    }

    public boolean addVisit(String name, int date){
        for(int i = 0; i < people.size(); i++){
            if(people.get(i).getName().equalsIgnoreCase(name)){
                people.get(i).incrementVisits();
                people.get(i).addDay(dates.get(date).toStringPerson());
                dates.get(date).addVisitor(name);
                return true;
            }
        }
        System.out.println(\"Person not found\");
        return false;
    }

    public boolean addVisit(String name, int visits, int date){
        for(int i = 0; i < people.size(); i++){
            if(people.get(i).getName().equalsIgnoreCase(name)){
                people.get(i).incrementVisits(visits);
                dates.get(date).addVisitor(name, visits);
                people.get(i).addDay(dates.get(date).toStringPerson(), visits);
                return true;
            }
        }
        System.out.println(\"Person not found\");
        return false;
    }

    public boolean regAdd(int date){
        dates.get(date).addRegular();
        return true;
    }

    public boolean regAdd(int date, int visits){
        dates.get(date).addRegular(visits);
        return true;
    }

    public boolean helpFunction(){
        File fin = new File(\"help.txt\");
        if(!fin.exists()){
            System.out.println(\"I\'m sorry the help file has become corrupted :(\");
            System.out.println(\"Please contact the maker of this program to fix it\");
            System.out.println(\"Upon contact he will probably let out a loud UGH\");
        }
        else{
            try{
                FileReader fr = new FileReader(fin);
                BufferedReader br = new BufferedReader(fr);
                String line;
                while((line = br.readLine()) != null){
                    System.out.println(line);
                }
            } catch (FileNotFoundException fnf) {
                //This line is completely pointless as the if function above serves its purpose
                System.out.println(\"File was not found\");
            } catch (IOException e) {
                e.printStackTrace();
            }


        }
        return true;
    }

    public boolean checkExistence(String name){
        for(int i = 0; i < people.size(); i++){
            if(people.get(i).getName().equalsIgnoreCase(name)){
                return true;
            }
        }
        return false;
    }

    public int getPersonPosition(String name){
        for(int i = 0; i < people.size(); i++){
            if(people.get(i).getName().equalsIgnoreCase(name)){
                return i;
            }
        }
        return -1;
    }

    public boolean printPersonDates(String name){
        int x = getPersonPosition(name);
        people.get(x).printDates();
        return true;
    }


    public String changeMonth(){
        Scanner kbd = new Scanner(System.in);
        String input;
        boolean continueProgram = false;
        boolean monthContinue = false;
        //Recieve the date
        do{
            System.out.println(\"What is the month?\");
            input = kbd.nextLine();
            monthContinue = testDateValidity(input, 1);
            if(monthContinue){
                continueProgram = true;
            }
        } while (!continueProgram);
        String month = input;
        return month;
    }

    public String changeDay(){
        Scanner kbd = new Scanner(System.in);
        String input;
        boolean continueProgram = false;
        boolean dayContinue = false;
        //Recieve the date
        do{
            System.out.println(\"What is the day?\");
            input = kbd.nextLine();
            dayContinue = testDateValidity(input, 2);
            if(dayContinue){
                continueProgram = true;
            }
        } while (!continueProgram);
        String day = input;
        return day;
    }

    public boolean yesOrNo(){
        Scanner kbd = new Scanner(System.in);
        String input;
        do{
            System.out.println(\"Are you sure? Y or N\");
            input = kbd.nextLine();
        } while(!checkYes(input));
        if(input.equalsIgnoreCase(\"y\") || input.equalsIgnoreCase(\"yes\")){
            return true;
        }
        else if(input.equalsIgnoreCase(\"n\") || input.equalsIgnoreCase(\"no\")){
            return false;
        }
        else{
            return false;
        }
    }

    public boolean checkYes(String input){
        if(input.equalsIgnoreCase(\"y\") || input.equalsIgnoreCase(\"yes\")){
            return true;
        }
        else if(input.equalsIgnoreCase(\"n\") || input.equalsIgnoreCase(\"no\")){
            return true;
        }
        else{
            return false;
        }
    }

    public boolean checkForExistence(String input){
        for(int i = 0; i < people.size(); i++ ){
            if(input.equalsIgnoreCase(people.get(i).getName())){
                return false;
            }
        }
        return true;
    }
    //Main Function
    public static void main(String[] args){
        main pool = new main();
        Scanner kbd = new Scanner(System.in);
        String input;
        int numberData;
        boolean continueProgram = false;
        String month;
        String day;
        int dayPosition;
        String dateString;

        System.out.println(\"Welcome to the Pool Database Management System\");
        System.out.println(\"Copyright 2011 by Dalton Dick\");

        boolean monthContinue = false;
        //Recieve the date
        do{
            System.out.println(\"What is the month?\");
            input = kbd.nextLine();
            monthContinue = pool.testDateValidity(input, 1);
            if(monthContinue){
                continueProgram = true;
            }
        } while (!continueProgram);
        month = input;

        continueProgram = false;
        boolean dayContinue = false;
        //Recieve the date
        do{
            System.out.println(\"What is the day?\");
            input = kbd.nextLine();
            dayContinue = pool.testDateValidity(input, 2);
            if(dayContinue){
                continueProgram = true;
            }
        } while (!continueProgram);
        day = input;

        //Adding the date object or finding the date already stored
        if(pool.findDayPosition(month, day) != -1){
            dayPosition = pool.findDayPosition(month, day);
            System.out.println(\"Date already exists, using.\");
        }
        else{
            Date dayObject = new Date(month, day);
            pool.dates.add(dayObject);
            dayPosition = pool.findDayPosition(month, day);
            System.out.println(\"Date added\");
        }

        continueProgram = true;
        boolean needsAFunction = true;
        while(continueProgram){
            System.out.println(\"Please enter a command\");
            input = kbd.nextLine();
            String[] tokens = input.split(\" \");

            if(tokens[0].equalsIgnoreCase(\"help\")){
                if(tokens.length == 1){
                    pool.helpFunction();
                }
                else{
                    System.out.println(\"Invalid Command\");
                }
            }
            else if(tokens[0].equalsIgnoreCase(\"new\")){
                if(tokens.length == 1){
                    pool.newPerson();
                }
                else{
                    System.out.println(\"Invalid Command\");
                }
            }
            else if(tokens[0].equalsIgnoreCase(\"print\")){
                if(tokens.length == 2){
                    if(tokens[1].equalsIgnoreCase(\"people\")){
                        pool.printPeopleList();
                    }
                    else if(tokens[1].equalsIgnoreCase(\"dates\")){
                        pool.printListOfDates();
                    }
                    else if(tokens[1].equalsIgnoreCase(\"current\")){
                        pool.printCurrentPeople(dayPosition);
                    }
                }//End if Statement
                else if(tokens.length == 3){
                    if(pool.checkExistence(tokens[1])){
                        if(tokens[2].equalsIgnoreCase(\"dates\")){
                            pool.printPersonDates(tokens[1]);
                        }
                        else{
                            System.out.println(\"Invalid\");
                        }
                    }
                    else{
                        System.out.println(\"Person does not exist\");
                    }

                }
            }
            else if(tokens[0].equalsIgnoreCase(\"quit\") || tokens[0].equalsIgnoreCase(\"q\") || tokens[0].equalsIgnoreCase(\"exit\")){
                System.out.println(\"Exiting System\");
                System.exit(0);
            }
            else if(tokens[0].equalsIgnoreCase(\"add\")){
                if(tokens.length == 1){
                    System.out.println(\"Invalid use of the command\");
                }
                else if(tokens.length == 2){
                    pool.addVisit(tokens[1], dayPosition);
                }
                else if(tokens.length == 3){
                    try{
                        int x = Integer.parseInt(tokens[2]);
                        pool.addVisit(tokens[1], x, dayPosition);
                    } catch (NumberFormatException nfe){
                        System.out.println(\"Not a number\");
                    }//End try catch block
                }//End else if
            }
            else if(tokens[0].equalsIgnoreCase(\"change\")){
                if(tokens.length == 2){
                    if(tokens[1].equalsIgnoreCase(\"date\")){
                        month = pool.changeMonth();
                        day = pool.changeDay();
                        if(pool.findDayPosition(month, day) != -1){
                            dayPosition = pool.findDayPosition(month, day);
                            System.out.println(\"Date already exists, using.\");
                        }
                        else{
                            Date dayObject = new Date(month, day);
                            pool.dates.add(dayObject);
                            dayPosition = pool.findDayPosition(month, day);
                            System.out.println(\"Date added\");
                        }
                    }
                    else{
                        System.out.println(\"Invalid Command\");
                    }
                }
                else{
                    System.out.println(\"Invalid Command\");
                }

            }
            else if(tokens[0].equalsIgnoreCase(\"regular\") || tokens[0].equalsIgnoreCase(\"reg\")){
                if(tokens.length == 1){
                    pool.regAdd(dayPosition);
                }
                else if(tokens.length == 2){
                    try{
                        pool.regAdd(dayPosition, Integer.parseInt(tokens[1]));
                    } catch (NumberFormatException nfe) {
                        System.out.println(\"Not correct input\");
                    }
                }

            }
            else{
                System.out.println(\"Invalid Command\");
            }
        }
    }
}
    
2020-01-07 2 条评论
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没有找到相关结果

    已邀请:

    骨酚柯

    检查以下示例： 
    ArrayList<Student> list = new ArrayList<Student>();
list.add(student1);
list.add(student2);
list.add(student3);

FileOutputStream fos;
try 
{
   fos = new FileOutputStream(FILENAME);
   ObjectOutputStream oos = new ObjectOutputStream(fos);
   oos.writeObject(list);
   // read back
   FileInputStream fis = new FileInputStream(FILENAME);
   ObjectInputStream ois = new ObjectInputStream(fis);
   Object obj = ois.readObject();
   ArrayList<Student> listFromFile = (ArrayList) obj;
   for (Student student: listFromFile) 
   {
     System.out.println(student.toString());
   }     
} 
catch (FileNotFoundException e) 
{
  e.printStackTrace();           
}
        
    2020-01-07 0 0
    分享
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