How to find in classpath:spring

Spring can load files from classpath, such as the Bean's definition file, by specifying classpath*: with the classpath: prefix plus path. classpath*: Appears to load the same file from multiple jar Files. classpath: only the first file found is Loaded.

For example, the package ' com.test.rs ' in Resource1.jar has a ' jarappcontext.xml ' file that reads as Follows:

<bean name= "processorimpla" class= "com.test.spring.di.ProcessorImplA"/>

The package ' com.test.rs ' in Resource2.jar also has a ' jarappcontext.xml ' file that reads as Follows:

<bean id= "processorimplb" class= "com.test.spring.di.ProcessorImplB"/>

You can load the files in the two jar packages by using the following code

ApplicationContext CTX = new Classpathxmlapplicationcontext ("classpath*:com/test/rs/jarappcontext.xml");

If you write the following code, you can only find one of the XML files (the order depends on the load order of the jar Packages)

ApplicationContext CTX = new Classpathxmlapplicationcontext ("classpath:com/test/rs/jarappcontext.xml");

Classpath*: is used for multiple component (eventually released into different jar packages) in parallel development, the respective bean definition files according to certain rules: package+filename, The callers who use these component can load the files in.

Classpath*: loading uses the ClassLoader getResources() method, and if it is running on a different Java EE server, they may behave differently when working with the jar file because the application server provides its own ClassLoader Implementation. To test classpath*: Whether it is valid, you can test it with ClassLoader from the jar file in the classpath to load the file: getClass().getClassLoader().getResources("<someFileInsideTheJar>") . (the example above is the state running in Sun's Jre)

From Spring's source code, in the Pathmatchingresourcepatternresolver class, we can better understand its handling: if it starts with classpath*, it will traverse Classpath.

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2. Protected resource[] findallclasspathresources (String Location) throws IOException {
4. String Path = location;
6. if (path.startswith ("/")) {
8. Path = path.substring (1);
10. }
12. Enumeration resourceurls = getClassLoader (). getresources (path);
14. set<resource> result = new linkedhashset<resource> (16);
16. while (resourceurls.hasmoreelements ()) {
18. URL url = (url) resourceurls.nextelement ();
20. Result.add (convertclassloaderurl (url));
22. }
24. return Result.toarray (new Resource[result.size ()));
26. }

http://blog.csdn.net/kkdelta/article/details/5560210, introduces all the matching names found in Java traversal classpath.

In addition, when loading resource, the meanings of the other prefixes are as follows: note that classpath* can only be used with the path specified by the configuration file and cannot be used in parameters used for getresource. such as Appcontext.getresource (" Classpath*:conf/bfactoryctx.xml ") will be abnormal.

prefix	Example	Description
Classpath	classpath:com/myapp/config.xml	Loaded from the Classpath.
File	file:/data/config.xml	As URL loaded from the file System.
http	http://myserver/logo.png	As URL Load.
(none)	/data/config.xml	According ApplicationContext to the Judgment.

From the source of spring can see the reason: if it is classpath: start, load from classpath, otherwise try the url, if failed, call Getresourcebypath

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2. Public Resource GetResource (String Location) {
4. Assert.notnull (location, "must is not null");
6. if (location.startswith (classpath_url_prefix)) {
8. return new Classpathresource (location.substring (classpath_url_prefix.length ()), getclassloader ());
10. }
12. else {
14. try {
16. //Try to parse the location as a URL ...
18. URL url = new URL (location);
20. return New Urlresource (url);
22. }
24. catch (malformedurlexception Ex) {
26. //No URL, Resolve as Resource path.
28. return Getresourcebypath (location);
30. }
32. }
34. }

Getresourcebypath will be overwritten by different ApplicationContext Implementations.

If the genericwebapplicationcontext is covered as follows:

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2. Protected Resource Getresourcebypath (String Path) {
4. return new Servletcontextresource (this.servletcontext, path);
6. }
10. If the filesystemxmlapplicationcontext is covered as follows:
14. Protected Resource Getresourcebypath (String Path) {
16. if (path! = null && path.startswith ("/")) {
18. Path = path.substring (1);
20. }
22. return New Filesystemresource (path);
24. }

It is still common in Java to read files when loading from a file:

The way to get InputStream as Classpathresource is to use class Loader.

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1. Public InputStream getInputStream () throws IOException {
2. InputStream is;
3. if (this.clazz! = Null) {
4. is = This.clazz.getResourceAsStream (this.path);
5. }

The way to get inputstream, as filesystemresource, is to use Fileinputstream.

Public InputStream getInputStream () throws IOException {
return new FileInputStream (this.file);
}

The way to get inputstream, as servletcontextresource, is to use Servletcontext.getresourceasstream.

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1. public inputstream getinputstream ()  throws ioexception {  
2.      inputstream is = this.servletcontext.getresourceasstream ( Span class= "keyword" >this.path)   
3.     if  (is == null)  {  
4.         throw new  filenotfoundexception ( "could not open "  + getdescription () );   
5.     }  
6.      return is;  
7. } 

How to find in classpath:spring