Saving is a story apart. This won't work if the file is located in a JAR file. If you can ensure that the file is expanded and is writable, then convert the URL from getResource() to File.
一般情况下你不能。从类加载器加载的资源可以是任何内容：目录中的文件、嵌入到 jar 文件中的文件，甚至是通过网络下载的文件。
In the general case you cannot. Resources loaded from a classloader can be anything: files in directories, files embedded in jar files or even downloaded over the network.
URI uri = this.getClass().getProtectionDomain().getCodeSource().getLocation().toURI();
File file = new File(new File(uri), PROPERTIES_FILE);
FileOutputStream out = new FileOutputStream(createPropertiesFile(PROPERTIES_FILE));
prop.store(out, null);
If you want the file in the same classpath as the current class (Example: project/classes):
URI uri = this.getClass().getProtectionDomain().getCodeSource().getLocation().toURI();
File file = new File(new File(uri), PROPERTIES_FILE);
FileOutputStream out = new FileOutputStream(createPropertiesFile(PROPERTIES_FILE));
prop.store(out, null);
If you want the file in a different classpath (Example: progect/test-classes), just replace this.getClass() with something like TestClass.class.
Read Properties from Classpath:
Properties prop = new Properties();
System.out.println("Resource: " + getClass().getClassLoader().getResource(PROPERTIES_FILE));
InputStream in = getClass().getClassLoader().getResourceAsStream(PROPERTIES_FILE);
if (in != null) {
try {
prop.load(in);
} finally {
in.close();
}
}
Write Properties to Classpath:
Properties prop = new Properties();
prop.setProperty("Prop1", "a");
prop.setProperty("Prop2", "3");
prop.setProperty("Prop3", String.valueOf(false));
FileOutputStream out = null;
try {
System.out.println("Resource: " + createPropertiesFile(PROPERTIES_FILE));
out = new FileOutputStream(createPropertiesFile(PROPERTIES_FILE));
prop.store(out, null);
} finally {
if (out != null) out.close();
}
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使用
ClassLoader#getResource()或getResourceAsStream()从类路径获取它们作为URL或InputStream。或者，如果它与当前类在同一个包中，您也可以通过以下方式获取它：
保存是一个故事。如果文件位于 JAR 文件中，这将不起作用。如果您可以确保文件已展开且可写，请将
URL从getResource()转换为File。然后，您可以构造一个
FileOutputStream与它一起。相关问题：
getResourceAsStream()与FileInputStreamUse
ClassLoader#getResource()orgetResourceAsStream()to obtain them asURLorInputStreamfrom the classpath.Or if it is in the same package as the current class, you can also obtain it as follows:
Saving is a story apart. This won't work if the file is located in a JAR file. If you can ensure that the file is expanded and is writable, then convert the
URLfromgetResource()toFile.You can then construct a
FileOutputStreamwith it.Related questions:
getResourceAsStream()versusFileInputStream如果您的类是从文件系统加载的，您可以尝试以下操作。
要获取该路径中的文件，您可以使用
You can try the following provided your class is loaded from a filesystem.
To get a file in that path you can use
一般情况下你不能。从类加载器加载的资源可以是任何内容：目录中的文件、嵌入到 jar 文件中的文件，甚至是通过网络下载的文件。
In the general case you cannot. Resources loaded from a classloader can be anything: files in directories, files embedded in jar files or even downloaded over the network.
new File(".").getAbsolutePath() + "relative/path/to/your/files";new File(".").getAbsolutePath() + "relative/path/to/your/files";这是 Peter 响应的扩展：
如果您希望文件与当前类位于同一类路径中（示例：project/classes）：
如果您希望文件位于不同的类路径中（示例：progect/test-classes），只需替换
this.getClass()与类似TestClass.class的内容。从类路径读取属性：
将属性写入类路径：
在类路径上创建文件对象：
This is an expansion on Peter's response:
If you want the file in the same classpath as the current class (Example: project/classes):
If you want the file in a different classpath (Example: progect/test-classes), just replace
this.getClass()with something likeTestClass.class.Read Properties from Classpath:
Write Properties to Classpath:
Create the File Object on the Classpath:
根据系统属性文档，您可以将其作为“java.class.path”属性访问：
According to system properties documentation, you can access this as the "java.class.path" property: