Thread.currentThread（）。getContextClassLoader（）。getResourceAsStream多次读取属性文件

Question

I have a property file named sysconfig.properties, I want to read it multiple times, because it is mutable.But I found when I changed the content of the sysconfig.properties then I read the content that is imutable, which is the same with the first time I read from the systemconfig.properties file.The content of the sysconfig.propertes file as follows:

isInitSuccess=TRUE
isStartValid=2013

May be sometime it will been changed as follows:

isInitSuccess=FALSE
isStartValid=2013

The code of read the properties file as follows:

InputStream inStream = Thread.currentThread().getContextClassLoader().getResourceAsStream(filePath);     

I use the code read the file mutilple times, but every time the "isInitSuccess" is "TRUE", even though I changed the isInitSuccess=FALSE.Is the system just read it one time, then I read the file, it just get the input stream from the memory? But when I use the code below, it will work fine:

InputStream inStream = new FileInputStream(new File(strPath));

I googled, but I did not find any help, the problem confused me a lot, any help would be appreciate.

Answer 1

You need to read up on what the classpath is.

In short, Java has a concept of classpath which includes all the resources ( .class files, .properties files, and anything really) it needs to run. When you use ClassLoader#getResourceAsStream(String) , you're actually getting the InputStream of a classpath resource. This resource can be a physical resource on disk or it can be in an archive.

When you use a FileInputStream , you are getting the InputStream of a file on disk.

The InputStream from the ClassLoader and the one from the FileInputStream do not correspond to the same file.

You should read up on how your IDE (or whatever build system) handles your files.