无法在可执行文件中访问资源 [英] Can't Access Resources In Executable Jar

问题描述

有人可以指出我在这里做错了什么。

Can someone please point out what I'm doing wrong here.

我有一个生成并发送HTML电子邮件的小天气应用程序。使用下面的代码，当我从Eclipse运行它时，一切正常。我的电子邮件生成，它能够访问我的图像资源，并发送包含附件的电子邮件。

I have a small weather app that generates and sends an HTML email. With my code below, everything works fine when I run it from Eclipse. My email gets generated, it's able to access my image resources and it sends the email with the included attachment.

然而，当我通过运行构建可执行jar时mvn install 并使用 java -jar NameOfMyJar.jar 运行jar我得到 java.io.FileNotFound 我的图片资源的例外。

However, when I build the executable jar by running mvn install and run the jar using java -jar NameOfMyJar.jar I get java.io.FileNotFound Exceptions for my image resource.

我知道我必须对我如何访问我的图像资源做错了什么，我只是不明白为什么它在没有打包的情况下工作正常，但每当我打包时都会爆炸它是一个罐子。

I know that I have to be doing something wrong with how I'm accessing my image resources, I just don't understand why it works fine when it's not packaged, but bombs out whenever I package it into a jar.

任何建议都非常感谢。

我的项目布局

我如何访问我的图片资源

//Setup the ATTACHMENTS
        MimeBodyPart attachmentsPart = new MimeBodyPart();
        try {
            attachmentsPart.attachFile("resources/Cloudy_Day.png");
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }   

---

StackTrace

    Exception in thread "main" java.lang.RuntimeException: javax.mail.MessagingException: IOException while sending message;
  nested exception is:
    java.io.FileNotFoundException: resources/Cloudy_Day.png (No such file or directory)
    at Utilities.SendEmailUsingGmailSMTP.SendTheEmail(SendEmailUsingGmailSMTP.java:139)
    at Utilities.SendEmailUsingGmailSMTP.SendWeatherEmail(SendEmailUsingGmailSMTP.java:66)
    at Weather.Main.start(Main.java:43)
    at Weather.Main.main(Main.java:23)
Caused by: javax.mail.MessagingException: IOException while sending message;
  nested exception is:
    java.io.FileNotFoundException: resources/Cloudy_Day.png (No such file or directory)
    at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1167)
    at javax.mail.Transport.send0(Transport.java:195)
    at javax.mail.Transport.send(Transport.java:124)
    at Utilities.SendEmailUsingGmailSMTP.SendTheEmail(SendEmailUsingGmailSMTP.java:134)
    ... 3 more
Caused by: java.io.FileNotFoundException: resources/Cloudy_Day.png (No such file or directory)
    at java.io.FileInputStream.open(Native Method)
    at java.io.FileInputStream.<init>(FileInputStream.java:146)
    at javax.activation.FileDataSource.getInputStream(FileDataSource.java:97)
    at javax.activation.DataHandler.writeTo(DataHandler.java:305)
    at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1485)
    at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:865)
    at javax.mail.internet.MimeMultipart.writeTo(MimeMultipart.java:462)
    at com.sun.mail.handlers.multipart_mixed.writeTo(multipart_mixed.java:103)
    at javax.activation.ObjectDataContentHandler.writeTo(DataHandler.java:889)
    at javax.activation.DataHandler.writeTo(DataHandler.java:317)
    at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1485)
    at javax.mail.internet.MimeMessage.writeTo(MimeMessage.java:1773)
    at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1119)
    ... 6 more

推荐答案

其他人使用 getResourceAsStream是正确的，但路径有点棘手。您在资源文件夹中看到小包装图标？这表示 resource 文件夹中的所有文件都将放入类路径的根目录中。就像 src / main / java 中的所有包都放在根目录中一样。所以你会从路径中取出资源

Others are correct with the use of getResourceAsStream, but the path is a little tricky. You see the little package icon in the resources folder? That signifies that all the files in the resource folder will be put into the root of the classpath. Just like all the packages in src/main/java are put in the root. So you would take out the resources from the path

InputStream is = getClass().getResourceAsStream("/Cloudy_Day.png");

一边： Maven有文件结构约定。类路径资源通常放在 src / main / resources 中。如果你在 src / main 中创建一个 resources dir，Eclipse会自动选择它，并创建一个小包您应该在项目资源管理器中看到的路径 src / main / resource 的图标。这些文件也会转到root，并且可以以相同的方式访问。我会修复文件结构以遵循此约定。

An aside: Maven has a file structure conventions. Class path resources are usually put into src/main/resources. If you create a resources dir in the src/main, Eclipse should automatically pick it up, and create the little package icon for a path src/main/resource that you should see in the project explorer. These files would also go to the root and could be accessed the same way. I would fix the file structure to follow this convention.

注意： A MimeBodyPart ，可以构建一个 InputStream （正如Bill Shannon所说，这是不正确的）。正如他在下面的评论中提到的那样

Note: A MimeBodyPart, can be Constructed from an InputStream (As suggested by Bill Shannon, this is incorrect). As mentioned in his comment below

你也可以使用

mbp.setDataHandler(new DataHandler(new ByteArrayDataSource(
          this.getClass().getResourceAsStream("/Cloudy_Day.png", "image/png"))));

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