我从一个ArrayList获取内存地址，需要信息 [英] I am getting the memory address from an arraylist, need info

问题描述

我把文本文件，并填写一个ArrayList。对文件进行测试，我打印出来之前，我继续前进。我只能看到存储器地址，而不是从文件中实际信息。有什么简单而明显的可能是我失踪？

 公共类TriviaQuestion {私人字符串的球员;
私人字符串类;
私人字符串的问题;
私人字符串的答案;
私人INT得分= 0;/ **
 *
 * /
公共TriviaQuestion（）{
    玩家=未知;
    类=未知;
    问题=未知;
    回答=未知;
    得分= 0;
}公共TriviaQuestion（串类，弦乐的问题，弦乐答案）{}
公共TriviaQuestion（字符串播放器，串类，弦乐的问题，
        字符串的回答，诠释得分）{
    超（）;
    this.player =玩家;
    this.category =类别;
    this.question =问题;
    this.answer =答案;
    this.score =得分;
}
/ **
 返回：玩家
 * /
公共字符串getPlayer（）{
    返回的球员;
}
/ **
 * @参数播放机播放器设定
 * /
公共无效setPlayer（字符串球员）{
    this.player =玩家;
}
/ **
 返回：类别
 * /
公共字符串的getCategory（）{
    返回类;
}
/ **
 * @参数类别的类别设置
 * /
公共无效setCategory（串类）{
    this.category =类别;
}
/ **
 返回：问题
 * /
公共字符串getQuestion（）{
    返回的问题;
}
/ **
 * @参数质疑的问题设置
 * /
公共无效setQuestion（字符串问题）{
    this.question =问题;
}
/ **
 返回：答案
 * /
公共字符串的getAnswer（）{
    返回的答案;
}
/ **
 * @参数回答的答案为设置
 * /
公共无效setAnswer（字符串回答）{
    this.answer =答案;
}
/ **
 返回：比分
 * /
公众诠释getScore（）{
    返回分数;
}
/ **
 * @参数得分将比分设置
 * /
公共无效setScore（INT分数）{
    this.score =得分;
}}
 

该测试仪

 进口的java.io.File;
进口java.io.IOException异常;
进口的java.util.ArrayList;
进口java.util.Scanner中;
公共类TriviaQuestionTester {/ **
 * @参数ARGS
 * /
公共静态无效的主要（字串[] args）抛出IOException     文件triviaFile =新的文件（trivia.txt）;    扫描仪triviaFile1 =新的扫描仪（triviaFile）;
    串lastKnownCategory =;    ArrayList的＆LT; TriviaQuestion＆GT; myList中=新的ArrayList＆LT; TriviaQuestion＆GT;（）;
    而（triviaFile1.hasNextLine（））{
        串currentLine = triviaFile1.nextLine（）;
        如果（！currentLine.isEmpty（））{
            TriviaQuestion currentQuestion =新TriviaQuestion（currentLine，currentLine，currentLine）;            如果（currentLine.endsWith（？））{
                currentQuestion.setCategory（lastKnownCategory）;
                currentQuestion.setQuestion（currentLine）;
                currentQuestion.setAnswer（triviaFile1.nextLine（））;
            }其他{
                currentQuestion.setCategory（currentLine）;
                currentQuestion.setQuestion（triviaFile1.nextLine（））;
                currentQuestion.setAnswer（triviaFile1.nextLine（））;
                lastKnownCategory = currentLine;
            }
            myList.add（currentQuestion）;
        }
    }
    triviaFile1.close（）;    的System.out.println（myList中）;}}
 

解决方案

  

有没有简单的东西，可能明显我失踪？

是 - 你没有覆盖的toString 在 TriviaQuestion ，所以你得到的默认实现>对象 ：

  

Object类的toString方法返回一个包含其中的对象是一个实例，该符号字符'@'的类名称的字符串，散列$ C的无符号十六进制再presentation对象$ C。换句话说，该方法返回字符串等于的值：

 的getClass（）。的getName（）+'@'+ Integer.toHexString（哈希code（））
 

只需添加这 TriviaQuestion ：

  @覆盖公共字符串的ToString（）{
    返回玩家：+球员+;类别：+类别
        +;问：+问题+，答：答案+
        +;得分：+分;
}
 

（或者使用的String.format 的方法中做同样的事情。）

I am taking a text file and filling an arraylist. To test the file I am printing it out before I move on. I am only able to see the memory address and not the actual info from the file. Is there something simple and probably obvious I'm missing?

public class TriviaQuestion {

private String player;
private String category;
private String question;
private String answer;
private int score = 0;

/**
 * 
 */


public TriviaQuestion() {
    player = "unknown";
    category = "unknown";
    question = "unknown";
    answer = "unknown";
    score = 0;
}

public TriviaQuestion(String category, String question, String answer){

}
public TriviaQuestion(String player, String category, String question,
        String answer, int score) {
    super();
    this.player = player;
    this.category = category;
    this.question = question;
    this.answer = answer;
    this.score = score;
}


/**
 * @return the player
 */
public String getPlayer() {
    return player;
}


/**
 * @param player the player to set
 */
public void setPlayer(String player) {
    this.player = player;
}


/**
 * @return the category
 */
public String getCategory() {
    return category;
}


/**
 * @param category the category to set
 */
public void setCategory(String category) {
    this.category = category;
}


/**
 * @return the question
 */
public String getQuestion() {
    return question;
}


/**
 * @param question the question to set
 */
public void setQuestion(String question) {
    this.question = question;
}


/**
 * @return the answer
 */
public String getAnswer() {
    return answer;
}


/**
 * @param answer the answer to set
 */
public void setAnswer(String answer) {
    this.answer = answer;
}


/**
 * @return the score
 */
public int getScore() {
    return score;
}


/**
 * @param score the score to set
 */
public void setScore(int score) {
    this.score = score;
}







}

The tester

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Scanner;


public class TriviaQuestionTester {

/**
 * @param args
 */
public static void main(String[] args) throws IOException {

     File triviaFile = new File("trivia.txt");

    Scanner triviaFile1 = new Scanner(triviaFile);
    String lastKnownCategory = "";

    ArrayList<TriviaQuestion> myList = new ArrayList<TriviaQuestion>();
    while (triviaFile1.hasNextLine()){
        String currentLine = triviaFile1.nextLine();
        if (!currentLine.isEmpty()) {
            TriviaQuestion currentQuestion = new TriviaQuestion(currentLine,     currentLine, currentLine);

            if (currentLine.endsWith("?")) {
                currentQuestion.setCategory(lastKnownCategory);
                currentQuestion.setQuestion(currentLine);
                currentQuestion.setAnswer(triviaFile1.nextLine());
            } else {
                currentQuestion.setCategory(currentLine);
                currentQuestion.setQuestion(triviaFile1.nextLine());
                currentQuestion.setAnswer(triviaFile1.nextLine());
                lastKnownCategory = currentLine;
            }
            myList.add(currentQuestion);
        }


    }
    triviaFile1.close();





    System.out.println(myList);

}

}

解决方案

Is there something simple and probably obvious I'm missing?

Yes - you haven't overridden toString in TriviaQuestion, so you're getting the default implementation from Object:

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

getClass().getName() + '@' + Integer.toHexString(hashCode())

Just add this to TriviaQuestion:

@Override public String toString() {
    return "Player: " + player + "; Category: " + category 
        + "; Question: " + question + "; Answer: " + answer
        + "; Score: " + score;
}

(Or use String.format within the method to do the same kind of thing.)

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