我试图从 MANIFEST.MF 文件中获取一些属性,但它们返回 null。
list
Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Built-By: jenkins
Build-Time: 2016-04-09T18:02:46Z Class-Path: spigot-1.8-R0.1-SNAPSHOT.jar Created-By: Apache Maven 3.3.9
Build-Jdk: 1.8.0_77
Name: Build Details
Implementation-SCM-Revision: SomeCommit
Implementation-Build-Number: SomeBuildNumber
Implementation-Title: SomeTitle
Implementation-Version: 4.0.0-SNAPSHOT
代码(此代码与使用的代码不完全相同,但几乎相同)
第一次尝试
public void doStuff() {
String version;
InputStream stream = Main.class.getClassLoader().getResourceAsStream("META-INF/MANIFEST.MF");
Properties properties = new Properties();
if (stream != null) {
try {
properties.load(stream);
version = properties.getProperty("Implementation-SCM-Revision"); //This is null
} catch (IOException ex) {
//TODO handle exception
}
}
第二次尝试
public void doStuff() {
Enumeration resEnum;
try {
resEnum = Thread.currentThread().getContextClassLoader().getResources(JarFile.MANIFEST_NAME);
while (resEnum.hasMoreElements()) {
try {
URL url = (URL)resEnum.nextElement();
InputStream is = url.openStream();
if (is != null) {
Manifest manifest = new Manifest(is);
Attributes mainAttribs = manifest.getMainAttributes();
String version = mainAttribs.getValue("Implementation-SCM-Revision"); //This is null
}
}
catch (Exception e) {
}
}
} catch (IOException e1) {
}
}
问题是,当打印 Attributes#getMainAttributes() 中的所有键时,它会打印 [Archiver-Version, Implementation-Title, Sealed, Specification-Version, Implementation-Version, Created-By, Manifest- Version, Build-Jdk, Specification-Vendor, Implementation-Vendor, Ant-Version, Specification-Title, Built-By, Main-Class]
,不包括Implementation-SCM-Revision
。这就是我想要得到的。
没有生成堆栈跟踪,它只是在打印 Implementation-SCM-Revision
属性时在控制台打印 null
最佳答案
Oracle 设法打破了 Manifest 类,尽管这很困难:
JDK-8201636 null value when trying to read manifest file attributes
另请参阅 MANIFEST entires 的类似错误:
JDK-8031748 Clarify jar entry orders in a jar file :
From the beginning, the jar file has an “undocumented” assumption that the MANIFEST.MF file and signature-related files (block and SF) should appear at the beginning (except for directory entries, say, META-INF/).
关于java - MANIFEST.MF 属性返回 null,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/36529228/