因为项目需要，要把一个zip/jar文件读入到后台服务器上，前台用户选择好zip/jar文件
以后，upload文件之后，从JarFile对象中循环读取JarEntry对象，然后根据JarFile的
API使用jarFile.getInputStream(JarEntry jarEntry)来读取每个JarEntry的内容。
可是最近他们想把文件读入变成基于inputstream的直接读取，从http请求中获取
inputstream之后可以直接读入。这样问题就来，怎么从流中知道每个JarEntry对象
一番研究之后，有了下面的代码：
package com.gloomyfish.image.study; import java.io.BufferedInputStream; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.util.HashMap; import java.util.Iterator; import java.util.jar.JarEntry; import java.util.jar.JarInputStream; import java.util.jar.Manifest; public class JarFileReader { private JarInputStream jarInput; private HashMap<String, ByteArrayOutputStream> entriesStreamMap; public JarFileReader(InputStream in) throws IOException { jarInput = new JarInputStream(in); entriesStreamMap = new HashMap<String, ByteArrayOutputStream>(); } public void readEntries() throws IOException { JarEntry entry = jarInput.getNextJarEntry(); String manifestEntry = null; while(entry != null) { System.out.println("Entry Name = " + entry.getName()); if("jp/co/sony/csl/nielsen/phoenix/objectremoval/Mark.class".equals(entry.getName())) { manifestEntry = entry.getName(); copyInputStream(jarInput, entry.getName()); } entry = jarInput.getNextJarEntry(); } System.out.println("Now!! + get jar entry inputstream again..."); InputStream inputStream = getCopy(manifestEntry); System.out.println(inputStream.read()); } public void copyInputStream(InputStream in, String entryName) throws IOException { if(!entriesStreamMap.containsKey(entryName)) { ByteArrayOutputStream _copy = new ByteArrayOutputStream(); int read = 0; int chunk = 0; byte[] data = new byte[256]; while(-1 != (chunk = in.read(data))) { read += data.length; _copy.write(data, 0, chunk); } entriesStreamMap.put(entryName, _copy); } } public InputStream getCopy(String entryName) { ByteArrayOutputStream _copy = entriesStreamMap.get(entryName); return (InputStream)new ByteArrayInputStream(_copy.toByteArray()); } public static void main(String[] args) { File jarFile = new File("D:\\agriculture\\clickremoval.jar"); try { InputStream in = new BufferedInputStream(new FileInputStream(jarFile)); JarFileReader reader = new JarFileReader(in); reader.readEntries(); } catch (IOException e) { e.printStackTrace(); } } }
