爪哇 - 如何写的ArrayList对象为txt文件？ [英] Java - How to write ArrayList Objects into txt file?

问题描述

/ **我有一些喜欢的方法添加，显示，排序，删除，并退出该实施ArrayList的功能。它工作正常，但问题是，已经加入了该对象将不保存在一个.txt文件，只是临时对象。所以，我需要将它们添加到文本文件，这样我可以显示和后删除它们。这里的codeS的一部分。
* /

 公共类的测试{    公共静态无效的主要（字串[] args）{
        字符串命令;
        INT索引= 0;
        扫描仪输入=新的扫描仪（System.in）;
        ArrayList的＆LT;串GT; MenuArray =新的ArrayList＆LT;串GT;（）;
        布尔OUT = FALSE;
        而（！出来）{
            System.out.print（请输入您的命令：）;
            命令= input.nextLine（）;
            //添加方法添加对象
            如果（Command.startsWith（ADD）|| Command.startsWith（加））{
                MenuArray.add（Command.substring（4）.toLowerCase（））;
                //索引对象
                指数++;
                / **我坚持在这里，也不会写入input.txt中
                但是BufferedWriter作家=新的BufferedWriter（新的FileWriter（
                        input.txt的））;
                尝试{
                    对于（字符串保存：MenuArray）{
                        INT I = 0;
                        writer.write（++ I + + save.toString（）。）;
                        writer.write（\\ n）;
                    }
                } {最后
                    writer.close（）;
                } * /
            }否则如果（Command.startsWith（EXIT）|| Comand.startsWith（退出））{
                出= TRUE;
            }
        }
    }
}
 

解决方案

您可以使用的 的ObjectOutputStream 以对象写入一个文件：

  {尝试
    FOS的FileOutputStream =新的FileOutputStream（输出）;
    ObjectOutputStream的OOS =新的ObjectOutputStream（FOS）;
    oos.writeObject（MenuArray）; //写MenuArray到的ObjectOutputStream
    oos.close（）;
}赶上（例外前）{
    ex.printStackTrace（）;
}
 

/** I have some methods likes add,display,sort,delete,and exit that implemented the ArrayList function. It works correctly, but the problem is that the objects that had been added were not saved on a .txt file, just the temporary objects. So I need to add them into text file,so that I can display and delete them later. Here's the part of the codes. */

public class testing {

    public static void main(String[] args) {
        String Command;
        int index = 0;
        Scanner input = new Scanner(System.in);
        ArrayList<String> MenuArray = new ArrayList<String>();
        boolean out = false;
        while (!out) {
            System.out.print("Enter your Command: ");
            Command = input.nextLine();
            // method ADD for adding object
            if (Command.startsWith("ADD ") || Command.startsWith("add ")) {
                MenuArray.add(Command.substring(4).toLowerCase());
                // indexing the object
                index++;
                /** i stuck here,it won't written into input.txt 
                BufferedWriter writer = new BufferedWriter(new FileWriter(
                        "input.txt"));
                try {
                    for (String save : MenuArray) {
                        int i = 0;
                        writer.write(++i + ". " + save.toString());
                        writer.write("\n");
                    }
                } finally {
                    writer.close();
                }*/
            } else if (Command.startsWith("EXIT") || Comand.startsWith("exit")) {
                out = true;
            }
        }
    }
}

解决方案

You can use ObjectOutputStream to write an object into a file:

try {
    FileOutputStream fos = new FileOutputStream("output");
    ObjectOutputStream oos = new ObjectOutputStream(fos);   
    oos.writeObject(MenuArray); // write MenuArray to ObjectOutputStream
    oos.close(); 
} catch(Exception ex) {
    ex.printStackTrace();
}

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