java里面如何扫描包

很多框架，比如springmvc，mybatis等使用注解，为了处理注解，必然要对包进行扫描，如果自己使用注解写通用代码，也要扫描包，下面代码给出扫描包的实现：

  1 　package com.jjh.common;
  2 
  3 
  4 import java.io.BufferedInputStream;
  5 import java.io.ByteArrayOutputStream;
  6 import java.io.IOException;
  7 import java.io.InputStream;
  8 import java.net.URL;
  9 import java.net.URLDecoder;
 10 import java.nio.file.FileSystem;
 11 import java.nio.file.FileVisitResult;
 12 import java.nio.file.Path;
 13 import java.nio.file.Paths;
 14 import java.nio.file.SimpleFileVisitor;
 15 import java.nio.file.attribute.BasicFileAttributes;
 16 import java.nio.file.spi.FileSystemProvider;
 17 import java.util.ArrayList;
 18 import java.util.HashMap;
 19 import java.util.List;
 20 import java.util.Objects;
 21 
 22 /**
 23  * @author Administrator
 24  *
 25  */
 26 public final class Files {
 27     /**
 28      * 
 29      */
 30     private Files() {
 31         // TODO Auto-generated constructor stub
 32     }
 33     
 34     static public byte[] read(InputStream in) throws IOException
 35     {
 36         byte[] temp=new byte[4096];
 37         ByteArrayOutputStream buffer=new ByteArrayOutputStream();
 38         BufferedInputStream bin=new BufferedInputStream(in);
 39         for(;;)
 40         {
 41             int len=bin.read(temp);
 42             if(len>-1)
 43                 buffer.write(temp, 0, len);
 44             else
 45                 break;
 46         }
 47         return buffer.toByteArray();
 48     }
 49 
 50 
 51     static public String[] scanPackage(String packageName) throws Exception {
 52         packageName=packageName.replaceAll("\\.","/");
 53         URL url = Thread.currentThread().getContextClassLoader().getResource(packageName);
 54         url=new URL(URLDecoder.decode(url.toString(), "UTF-8"));
 55         FileSystemProvider provider =null;
 56         if(url.getProtocol().equals("jar"))
 57         {
 58                provider = getZipFSProvider();
 59                 if (provider != null) {
 60                     try (FileSystem fs = provider.newFileSystem(Paths.get(url.getPath().replaceFirst("file:/", "").replaceFirst("!.*", "")),new HashMap<>())) {
 61                         return walkFileTree(fs.getPath(packageName),null).toArray(new String[0]);
 62                     } catch (Exception e) {
 63                         throw e;
 64                     }
 65                 }
 66         }
 67         else if(url.getProtocol().equals("file"))
 68         {
 69             int end=url.getPath().lastIndexOf(packageName);
 70             String basePath=url.getPath().substring(1, end);
 71             return walkFileTree(Paths.get(url.getPath().replaceFirst("/","")),Paths.get(basePath)).toArray(new String[0]);
 72         }
 73         return null;
 74     }
 75 
 76     private static List<String> walkFileTree(Path path,Path basePath) throws IOException{
 77         // TODO Auto-generated method stub
 78         final List<String> result=new ArrayList<>();
 79         java.nio.file.Files.walkFileTree(path, new SimpleFileVisitor<Path>(){
 80             private String packageName=Objects.isNull(basePath)?"":basePath.toString();
 81             /* (non-Javadoc)
 82              * @see java.nio.file.SimpleFileVisitor#visitFile(java.lang.Object, java.nio.file.attribute.BasicFileAttributes)
 83              */
 84             @Override
 85             public FileVisitResult visitFile(Path arg0, BasicFileAttributes arg1) throws IOException {
 86                 // TODO Auto-generated method stub
 87                 if(arg0.toString().endsWith(".class"))
 88                 {
 89                     result.add(arg0.toString().replace(packageName, "").substring(1).replace("\\", "/").replace(".class", "").replace("/", "."));
 90                 }
 91                 return FileVisitResult.CONTINUE;
 92             }
 93 
 94             /* (non-Javadoc)
 95              * @see java.nio.file.SimpleFileVisitor#preVisitDirectory(java.lang.Object, java.nio.file.attribute.BasicFileAttributes)
 96              */
 97             @Override
 98             public FileVisitResult preVisitDirectory(Path arg0, BasicFileAttributes arg1) throws IOException {
 99                 // TODO Auto-generated method stub
100                 //packageName=basePath==null?arg0.toString().substring(1, arg0.toString().length()-1).replace("/", "."):basePath.relativize(arg0).toString().replace("\\", ".");
101                 return FileVisitResult.CONTINUE;
102             }
103                 
104         });
105         return result;
106     }
107 
108     static public FileSystemProvider getZipFSProvider() {
109         for (FileSystemProvider provider : FileSystemProvider.installedProviders()) {
110             if ("jar".equals(provider.getScheme()))
111                 return provider;
112         }
113         return null;
114     }
115 
116     public static void main(String[] args) throws Exception {
117         //C:\Program Files\Apache Software Foundation\Tomcat 8.0\wtpwebapps\j2ee\WEB-INF\hawk.xml
118         // System.out.println(new
119         // URL("jar:file:/home/whf/foo.jar!/cn/fh").getPath());
120         for(String c:scanPackage("com.mysql.jdbc"))
121             System.out.println(c);
122         //System.out.println(Paths.get("file://C:/Users/Administrator/Desktop/pecker/build/classes/com/jjh/common"));
123         
124     }
125 
126 }
127 　

 

posted @ 2017-03-24 13:34  江金汉  阅读(3418)  评论(0)  编辑  收藏  举报