Java Scan Package

When we use SPRINGMVC, we know that SPRINGMVC can scan all the classes under the specified package, in the usual development, we also have such a scene, so today write a scan package of the tool class, the code is as follows:

 PackageCom.gujin.utils;ImportJava.io.File;ImportJava.io.FileFilter;ImportJava.io.IOException;ImportJava.net.JarURLConnection;ImportJava.net.URL;ImportJava.net.URLDecoder;ImportJava.util.ArrayList;ImportJava.util.Enumeration;ImportJava.util.List;ImportJava.util.jar.JarEntry;ImportJava.util.jar.JarFile; Public  class hqscanpackage{   /** whether to loop iteration **/   Booleanrecursive =true;/** Package Name Collection **/   PrivateList<string> Packagenames =NewArraylist<string> ();/** Filter **/   PrivateHqscanpackagefilter filter =NULL;/** Listener **/   PrivateHqscanpackagelistener listener =NULL;/** * Whether to loop iteration * * @return  */    Public Boolean isrecursive()   {returnRecursive }/** * Sets whether to loop iterations * * @param Recursive */    Public void setrecursive(BooleanRecursive) { This. recursive = recursive; }/** * Get filter * * @return  * *    PublicHqscanpackagefilterGetFilter()   {returnFilter }/** * Set Filter * * @param  Filter */    Public void SetFilter(Hqscanpackagefilter filter) { This. filter = filter; }/** * Get listener * * @return  * *    PublicHqscanpackagelistenerGetlistener()   {returnListener }/** * Set Listener * * @param Listener */    Public void Setlistener(Hqscanpackagelistener Listener) { This. Listener = Listener; }/** * Add Scan Package * * @param packagename */    Public void Addpackage(String PackageName) {if(PackageName = =NULL|| !packagename.matches ("[\\w]+ (\\.[ \\w]+) * "))      {Throw NewIllegalArgumentException ("Illegal package name."); } This. Packagenames.add (PackageName); }/** * Empty the scan package * /    Public void Clearpackage()   { This. Packagenames.clear (); }/** * Scan * * *    Public void Scan()   { for(String packagename:packagenames)      {Scan (packagename); }   }/** * Accept * * * @param clazz * @return * *   Private Boolean Accept(Class<?> clazz) {if( This. filter! =NULL)      {return  This. filter.accept (Clazz); }return true; }/** * Trigger Scan to legal class * * @param clazz * @return * *   Private void Trrigeronscanclass(Class<?> clazz) {if( This. Listener! =NULL)      { This. Listener.onscanclass (Clazz); }   }/** * Scan to class * * @param clazz * @return * *   Private void Onscanclass(Class<?> clazz) {if(Accept (Clazz))      {Trrigeronscanclass (clazz); }   }/** * Get all class * * @param packagename * @return * * from the package pack * *   Private void Scan(String PackageName) {//Get the name of the package and replace itString packagedirname = Packagename.replace ('. ','/');//Define a set of enumerations to be combined for looping to handle things under this directoryEnumeration<url> dirs =NULL;Try{dirs = Thread.CurrentThread (). Getcontextclassloader (). Getresources (Packagedirname);//loop iteration down          while(Dirs.hasmoreelements ()) {//Get Next elementURL url = dirs.nextelement ();//Get the name of the agreementString protocol = Url.getprotocol ();//If it is saved as a file on the server            if("File". Equals (protocol)) {//Get the physical path of the packageString FilePath = Urldecoder.decode (Url.getfile (),"UTF-8");//Scan files under the entire package in a file and add them to the collectionFindandaddclassesinpackagebyfile (PackageName, FilePath); }Else if("Jar". Equals (protocol)) {//If it is a jar package file               //define a jarfileJarfile jar =NULL;Try{//Get jarJar = ((jarurlconnection) url.openconnection ()). Getjarfile ();//Get an enumeration class from this jar packageenumeration<jarentry> entries = Jar.entries ();//The same loop iteration                   while(Entries.hasmoreelements ()) {//Get an entity in the jar can be a directory and some other files in the jar package such as meta-inf filesJarentry entry = Entries.nextelement (); String name = Entry.getname ();//If it starts with/                     if(Name.charat (0) =='/')                     {//Get the following stringName = Name.substring (1); }//If the first half and the defined package name are the same                     if(Name.startswith (Packagedirname)) {intIDX = Name.lastindexof ('/');//If the end of the "/" is a package                        if(IDX! =-1)                        {//Get package name replace "/" with "."PackageName = name.substring (0, IDX). Replace ('/','. '); }//If it can be iterated and is a package                        if(IDX! =-1) || Recursive) {//If it is a. class file and is not a directory                           if(Name.endswith (". Class") &&!entry.isdirectory ()) {//Remove the ". Class" from the back to get the real class nameString className = name.substring (packagename.length () +1, Name.length ()-6);Try{//Add to Classes                                 //Use Class.forName to trigger class static methodsClass<?> clazz = Thread.CurrentThread (). Getcontextclassloader (). LoadClass ( PackageName +'. '+ ClassName);                              Onscanclass (Clazz); }Catch(ClassNotFoundException e) {System.err.println ("Loading class error"); }                           }                        }                     }                  }               }Catch(IOException e) {System.err.println ("error getting file from Jar package while scanning user defined view");               E.printstacktrace (); }            }         }      }Catch(IOException e) {System.err.println ("Scan Error");      E.printstacktrace (); }   }/** * In the form of a file to get all classes under the package * * @param packagename * @param PackagePath * *   Private void Findandaddclassesinpackagebyfile(String PackageName, String PackagePath) {//Get the directory for this package to create a fileFile dir =NewFile (PackagePath);//If it does not exist or is not a directory, return directly      if(!dir.exists () | |!dir.isdirectory ()) {System.err.println ("User Defined package name"+ PackageName +"No files under ");return; }//If it exists, get all files under the package including directoryfile[] Dirfiles = Dir.listfiles (NewFileFilter () {//Custom filter rules If you can loop (including subdirectories) or files ending with a. Class (Compiled Java class file)          Public Boolean Accept(File file) {return(Recursive && file.isdirectory ()) | | (File.getname (). EndsWith (". Class")); }      });//Loop All Files       for(File file:dirfiles) {//If it is a directory then continue scanning         if(File.isdirectory ()) {Findandaddclassesinpackagebyfile (PackageName +"."+ File.getname (), File.getabsolutepath ()); }Else{//If the Java class file is removed, the following. Class only leaves the class nameString className = File.getname (). SUBSTRING (0, File.getname (). Length ()-6);Try{class<?> clazz = Thread.CurrentThread (). Getcontextclassloader (). LoadClass (Packa Gename +'. '+ ClassName);            Onscanclass (Clazz); }Catch(ClassNotFoundException e) {System.err.println ("Adding a user-defined view class error could not find the. class file for this class");            E.printstacktrace (); }         }      }   }/** * Scan packet filter * * @author Jianggujin * */    Public Static  interface hqscanpackagefilter {      /** * Accept * * * @param clazz * @return * *       Public Boolean Accept(Class<?> clazz); }/** * Scan Packet monitoring * * @author Jianggujin * */    Public Static  interface hqscanpackagelistener {      /** * Scan to legal class execution * * @param clazz */       Public void Onscanclass(Class<?> clazz); } Public Static void Main(string[] args) {Hqscanpackage Scanpackage =NewHqscanpackage ();      Scanpackage.addpackage (HQScanPackage.class.getPackage (). GetName ()); Scanpackage.setfilter (NewHqscanpackagefilter () {@Override          Public Boolean Accept(Class<?> clazz) {return true;      }      }); Scanpackage.setlistener (NewHqscanpackagelistener () {@Override          Public void Onscanclass(Class<?> clazz)         {System.out.println (clazz);      }      });   Scanpackage.scan (); }}

The following results can be obtained by running:

class com.gujin.utils.HQScanPackage$1
class com.gujin.utils.HQScanPackage$2
class com.gujin.utils.HQScanPackage$3
interface com.gujin.utils.HQScanPackage$HQScanPackageFilter
interface com.gujin.utils.HQScanPackage$HQScanPackageListener
class com.gujin.utils.HQScanPackage


Java Scan Package