java使用与已编译Jar相同文件夹中的图像不工作

Question

我所要做的就是使用一个图像创建一个JLabel，该图像与。jar，如果它不存在，它将加载位于。你自己。图片存在于文件夹中，但它始终默认为文件夹中的图片。罐子

String path = this.getClass().getProtectionDomain().getCodeSource().getLocation().getPath();

File logo = new File(path + "logo.png");

JLabel lblNewLabel_1;
if (logo.exists()){
    lblNewLabel_1 = new JLabel(new ImageIcon(logo.getPath()));
} else {
    lblNewLabel_1 = new JLabel(new ImageIcon(Main.class.getResource("/com/daniel/Coffee.png")));    
}

frame.getContentPane().add(lblNewLabel_1, BorderLayout.WEST);

final JLabel lblStatus = new JLabel(new ImageIcon(Main.class.getResource("/com/daniel/status1.png")));
frame.getContentPane().add(lblStatus, BorderLayout.EAST);

Answer 1

看起来您在path的末尾缺少了一个“/”。这样做：

String path = this.getClass().getProtectionDomain().getCodeSource().getLocation().getPath();
File logo = new File(new File(path).getParentFile(), "logo.png");
...

关键是首先为包含目录创建一个文件，然后使用构造函数File(File dir, String name)而不是字符串连接

此外，您应该提前检查文件夹和文件权限，为错误诊断提供适当的日志输出。为此，请使用canRead()而不是exists()（假设log可用作某些日志记录工具-替换为您选择的日志记录机制）：

String path = this.getClass().getProtectionDomain().getCodeSource().getLocation().getPath();
File sourceLocation = new File(path);

// go up in the hierarchy until there is a directory
while (sourceLocation != null && !sourceLocation.isDirectory()) {
    sourceLocation = sourceLocation.getParentFile();
    if (sourceLocation == null) {
        log.warn(path + " is not a directory but has no parent");
    }
}

if (sourceLocation != null && sourceLocation.canRead()) {
    File logo = new File(sourceLocation, "logo.png");
    if (logo.canRead()) {
        log.info("Using logo " + logo.getAbsolutePath());
        lblNewLabel_1 = new JLabel(new ImageIcon(logo.getPath()));
    } else {
        log.warn("can not read " + logo.getAbsolutePath());
    }
}

if (lblNewLabel_1 == null) {
    log.warn("logo location not accessible, using default logo: " + sourceLocation);
    lblNewLabel_1 = new JLabel(new ImageIcon(Main.class.getResource("/com/daniel/Coffee.png")));
}

// ...

Answer 2

诊断这个问题最简单的方法是像下面这样应用简单的System.out.println()

String path = this.getClass().getProtectionDomain().getCodeSource().getLocation().getPath(;
System.our.println("Jar path is "+path); <- you will see the actual path content here
File logo = new File(path + "logo.png");

检查结果，并根据需要调整连接路径。我猜这条路径要么指向与您想象的不同的目录，要么就是在末尾缺少一个File.separator。尝试并分享结果