java - FileWriter 上出现意外的 FileNotFoundException

Question

我正在尝试创建一个我将写入的简单文本文件。

我收到以下错误:

/Library/Java/Home/bin/java -Didea.launcher.port=7542 "-Didea.launcher.bin.path=/Applications/IntelliJ IDEA 14 CE.app/Contents/bin" -Dfile.encoding=UTF-8 -classpath "/Library/Java/Home/lib/deploy.jar:/Library/Java/Home/lib/dt.jar:/Library/Java/Home/lib/javaws.jar:/Library/Java/Home/lib/jce.jar:/Library/Java/Home/lib/jconsole.jar:/Library/Java/Home/lib/management-agent.jar:/Library/Java/Home/lib/plugin.jar:/Library/Java/Home/lib/sa-jdi.jar:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/charsets.jar:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/jsse.jar:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/ui.jar:/Library/Java/Home/lib/ext/apple_provider.jar:/Library/Java/Home/lib/ext/dnsns.jar:/Library/Java/Home/lib/ext/localedata.jar:/Library/Java/Home/lib/ext/sunjce_provider.jar:/Library/Java/Home/lib/ext/sunpkcs11.jar:/Users/Adam/IdeaProjects/Data Scraper/out/production/Data Scraper:/Applications/IntelliJ IDEA 14 CE.app/Contents/lib/idea_rt.jar" com.intellij.rt.execution.application.AppMain DataScraper
Exception in thread "main" java.io.FileNotFoundException: ~/Desktop/usernames.txt (No such file or directory)
at java.io.FileOutputStream.openAppend(Native Method)
at java.io.FileOutputStream.<init>(FileOutputStream.java:192)
at java.io.FileWriter.<init>(FileWriter.java:90)
at DataScraper.main(DataScraper.java:16)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)

代码:

import Resources.Constants;

    import java.awt.*;
    import java.io.*;

    public class DataScraper {
        public static void main(String[] args) throws Exception {

        File file = new File(Constants.filePath, Constants.fileName);
        Desktop desktop = Desktop.getDesktop();
        BufferedWriter Entry = new BufferedWriter(new FileWriter(file, true));

        }
    }




package Resources;

public class Constants {

    public static String baseURL = "www.lolking.net/summoner/na/";
    public static String filePath = "~//Desktop//";
    public static String fileName = "usernames.txt";

    public static int limit = 100;
}

如果有人可以指导我解决我做错的事情，我将不胜感激。我在我的 Windows 笔记本电脑上可以正常工作，但在我的 Mac 上，它似乎不起作用。

Answer 1

public static String filePath = "~//Desktop//";

这行不通。事实上，我很惊讶你说它可以在 Windows 上运行。

您的意思可能是“~”表示您的主目录...

只不过这对于 shell 来说意味着这个。 Java 不知道那是什么。它在这里有效地尝试做的是找到一个名为 '~' 的目录以及其中一个名为 Desktop 的条目。

使用System.getProperty("user.home")来了解您的主目录。

现在是 2015 年，所以不要使用 File。使用 java.nio.file 代替:

final Path path = Paths.get(System.getProperty("user.home"),
    "Desktop", "yourFileName");

try (
    final BufferedWriter writer = Files.newBufferedWriter(path,
        StandardCharsets.UTF_8, StandardOpenOption.APPEND);
) {
    // use the writer here
}