如何在另一个 class 中使用来自 'main' 方法的变量？连载

Question

这里是新手！我在 Java 中与 Save/Load 一起工作，我被踩了。我的代码正确地保存和加载了所有内容，但我无法在我的加载 class 中让这些加载的变量在 'public static void main' 之外的任何地方使用。我的意思是：

我有这个储蓄 class，非常好用：

package com.mestru.esport;

import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.util.Random;

public class NewPlayer {

public static void main (String args[])
{
    Random rand = new Random();

    int naturalTalent = rand.nextInt(10);
    int luck = rand.nextInt(20);
    int figure = rand.nextInt(50);
    int agility = rand.nextInt(30);
    int intelligence = rand.nextInt(30);
    int multiTasking = rand.nextInt(30);
    int stamina = rand.nextInt(30);

    try
    {
        FileOutputStream saveFile = new FileOutputStream("Player.sav");
        ObjectOutputStream save = new ObjectOutputStream(saveFile);

        save.writeObject(naturalTalent);
        save.writeObject(luck);
        save.writeObject(figure);
        save.writeObject(agility);
        save.writeObject(intelligence);
        save.writeObject(multiTasking);
        save.writeObject(stamina);

        save.close();
    }
    catch(Exception exc)
    {
        exc.printStackTrace();
    }
}
}

然后我有 class，它被设计用来加载并使加载的变量在其他 classes 中可用。如果加载部分工作完美，那么我就不能在 'main' 方法之外使用它们。

package com.mestru.esport;
import java.io.FileInputStream;
import java.io.ObjectInputStream;
import java.util.Random;

public class Player
{
int naturalTalent;
int luck;
int figure;
int agility;
int intelligence;
int multiTasking;
int stamina;

public static void main (String args[]) {

    int NEWnaturalTalent = 0;
    int NEWluck = 0;
    int NEWfigure = 0;
    int NEWagility = 0;
    int NEWintelligence = 0;
    int NEWmultiTasking = 0;
    int NEWstamina = 0;


    try {
        FileInputStream saveFile = new FileInputStream("Player.sav");
        ObjectInputStream save = new ObjectInputStream(saveFile);

        NEWnaturalTalent = (Integer) save.readObject();
        NEWluck = (Integer) save.readObject();
        NEWfigure = (Integer) save.readObject();
        NEWagility = (Integer) save.readObject();
        NEWintelligence = (Integer) save.readObject();
        NEWmultiTasking = (Integer) save.readObject();
        NEWstamina = (Integer) save.readObject();

        save.close();
    } catch (Exception exc) {
        exc.printStackTrace();
    }
    Player player = new Player();

    player.naturalTalent = NEWnaturalTalent;
    player.luck = NEWluck;
    player.figure = NEWfigure;
    player.agility = NEWagility;
    player.intelligence = NEWintelligence;
    player.multiTasking = NEWmultiTasking;
    player.stamina = NEWstamina;

}

public void test ()
{
    System.out.println("Natural Talent: " + naturalTalent);
    System.out.println("Luck: " + luck);
    System.out.println("Figure: " + figure);
    System.out.println("Agility: " + agility);
    System.out.println("Intelligence: " + intelligence);
    System.out.println("Multitasking: " + multiTasking);
    System.out.println("Stamina: " + stamina);
}

}

当我在另一个 class 中使用方法 'test' 时，所有值都等于 0。

所以这是我的问题。我能否以某种方式使所有实例变量等于 'main' 方法中加载的实例变量？我也不能在 'main' 方法之外使用 "try" :(

在此先感谢您的帮助<3 感谢您提供每条线索，我才刚刚开始学习。

Answer 1

加载时，您创建一个新的播放器，设置它然后丢弃它。

也许您打算设置当前玩家的字段。

你也不需要临时变量。您可以只设置字段。

public static void main(String... ignored) throws IOException {
    Player player = new Player();
    player.load("Player.sav");
    player.test();
}

public void load(String filename) throws IOException {
  try (FileInputStream saveFile = new FileInputStream(filename);
    ObjectInputStream save = new ObjectInputStream(saveFile)) {
    naturalTalent = (Integer) save.readObject();
    luck = (Integer) save.readObject();
    figure = (Integer) save.readObject();
    agility = (Integer) save.readObject();
    intelligence = (Integer) save.readObject();
    multiTasking = (Integer) save.readObject();
    stamina = (Integer) save.readObject();
  }
}

您可以将其写为文本，而不是以二进制形式写入此数据。这将使 read/edit 更容易，并且在此用例中它会更紧凑。即序列化一个 Integer 对象可能会大得惊人。

Answer 2

主要的 JavaCode Class

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Random;
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class TestProgram {

    public static void main(String[] args) throws FileNotFoundException {
        // TODO Auto-generated method stub

        Random rand = new Random();
        ArrayList<Integer> arl = new ArrayList<Integer>();

        int naturalTalent = rand.nextInt(10);
        int luck = rand.nextInt(20);
        int figure = rand.nextInt(50);
        int agility = rand.nextInt(30);
        int intelligence = rand.nextInt(30);
        int multiTasking = rand.nextInt(30);
        int stamina = rand.nextInt(30);

        String fileName = "/Users/rk4262/Player.txt";
        try {
            // Assume default encoding.
            FileWriter fileWriter = new FileWriter(fileName);

            // Always wrap FileWriter in BufferedWriter.
            BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);

            // Note that write() does not automatically
            // append a newline character.
            bufferedWriter.write("naturalTalent value is :" + naturalTalent);
            bufferedWriter.newLine();
            bufferedWriter.write("luck value is : " + luck);
            bufferedWriter.newLine();
            bufferedWriter.write("figure value is : " + figure);
            bufferedWriter.newLine();
            bufferedWriter.write("agility value is : " + agility);
            bufferedWriter.newLine();
            bufferedWriter.write("intelligence value is : " + intelligence);
            bufferedWriter.newLine();

            // Always close files.
            bufferedWriter.close();
        } catch (IOException ex) {
            System.out.println("Error writing to file '" + fileName + "'");
            // Or we could just do this:
            // ex.printStackTrace();
        }

        Player p = new Player();
        String s = p.readLine();
        System.out.println(s);

        Pattern pattern = Pattern.compile("[0-9]+");
        Matcher m = pattern.matcher(s);
        while (m.find()) {
            int n = Integer.parseInt(m.group());
            arl.add(n);

        }

        p.NEWnaturalTalent = arl.indexOf(0);
        p.NEWluck=arl.indexOf(1);
        p.NEWfigure=arl.indexOf(2);
        p.NEWagility=arl.indexOf(3);

    }

}

玩家代码Class

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Random;
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class TestProgram {

    public static void main(String[] args) throws FileNotFoundException {
        // TODO Auto-generated method stub

        Random rand = new Random();
        ArrayList<Integer> arl = new ArrayList<Integer>();

        int naturalTalent = rand.nextInt(10);
        int luck = rand.nextInt(20);
        int figure = rand.nextInt(50);
        int agility = rand.nextInt(30);
        int intelligence = rand.nextInt(30);
        int multiTasking = rand.nextInt(30);
        int stamina = rand.nextInt(30);

        String fileName = "/Users/rk4262/Player.txt";
        try {
            // Assume default encoding.
            FileWriter fileWriter = new FileWriter(fileName);

            // Always wrap FileWriter in BufferedWriter.
            BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);

            // Note that write() does not automatically
            // append a newline character.
            bufferedWriter.write("naturalTalent value is :" + naturalTalent);
            bufferedWriter.newLine();
            bufferedWriter.write("luck value is : " + luck);
            bufferedWriter.newLine();
            bufferedWriter.write("figure value is : " + figure);
            bufferedWriter.newLine();
            bufferedWriter.write("agility value is : " + agility);
            bufferedWriter.newLine();
            bufferedWriter.write("intelligence value is : " + intelligence);
            bufferedWriter.newLine();

            // Always close files.
            bufferedWriter.close();
        } catch (IOException ex) {
            System.out.println("Error writing to file '" + fileName + "'");
            // Or we could just do this:
            // ex.printStackTrace();
        }

        Player p = new Player();
        String s = p.readLine();
        System.out.println(s);

        Pattern pattern = Pattern.compile("[0-9]+");
        Matcher m = pattern.matcher(s);
        while (m.find()) {
            int n = Integer.parseInt(m.group());
            arl.add(n);

        }

        p.NEWnaturalTalent = arl.indexOf(0);
        p.NEWluck=arl.indexOf(1);
        p.NEWfigure=arl.indexOf(2);
        p.NEWagility=arl.indexOf(3);

    }

}

如何在另一个 class 中使用来自 'main' 方法的变量？连载

How to use variables from 'main' method in another class? Serialization

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main