以前遇到文件压缩的功能是都直接从网上找一个，随便测试一下能用就行了。既不关心效率也没有好好的测一下是否支持内嵌文件夹的压缩。

现在仔细测试才发现网上好多都不支持内嵌文件夹的压缩。 支持的不是有问题就是速度比较慢。

框架里jar包里的类诸如IOUtils，FileUtils里没有提供压缩的方法。连commons-compress.jar里都没有现成的。

我决定自己写一个。真写的时候发现不是那么容易。目标是 给定一个文件夹路径和一个输出路径，将给定文件夹里的所有东西都压缩到zip里。

在commons-compress的文档里发现有一个支持多线程压缩的类 ParallelScatterZipCreator。我决定试一试。

在github里找到 ScatterSample.java  和  ScatterSampleTest.java 这两个类。这个demo不支持带文件夹的压缩。文档里也没有给出带文件夹压缩的demo。没办法只能仔细阅

读这个demo从api里找线索了。

仔细摸索后，代码如下：

package test;import java.io.File;
import java.io.IOException;
import java.util.concurrent.ExecutionException;import org.apache.commons.compress.archivers.zip.ParallelScatterZipCreator;
import org.apache.commons.compress.archivers.zip.ScatterZipOutputStream;
import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
import org.apache.commons.compress.archivers.zip.ZipArchiveEntryRequest;
import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream;
import org.apache.commons.compress.parallel.InputStreamSupplier;public class ScatterSample {private String rootPath;ParallelScatterZipCreator scatterZipCreator = new ParallelScatterZipCreator();// ParallelScatterZipCreator api says:// 注意这个类不保证写入到输出文件的顺序。需要保持特定顺序的（manifests，文件夹）必须使用这个类的客户类进行处理// 通常的做法是 在调用这个类的writeTo方法前把这些东西写入到ZipArchiveOutputStreamScatterZipOutputStream dirs = ScatterZipOutputStream.fileBased(File.createTempFile("whatever-preffix", ".whatever"));public ScatterSample(String rootPath) throws IOException {this.rootPath = rootPath;}public void addEntry(final ZipArchiveEntry zipArchiveEntry, final InputStreamSupplier streamSupplier)throws IOException {if (zipArchiveEntry.isDirectory() && !zipArchiveEntry.isUnixSymlink()) {dirs.addArchiveEntry(ZipArchiveEntryRequest.createZipArchiveEntryRequest(zipArchiveEntry, streamSupplier));} else {scatterZipCreator.addArchiveEntry(zipArchiveEntry, streamSupplier);}}public void writeTo(final ZipArchiveOutputStream zipArchiveOutputStream)throws IOException, ExecutionException, InterruptedException {dirs.writeTo(zipArchiveOutputStream);dirs.close();scatterZipCreator.writeTo(zipArchiveOutputStream);}public String getRootPath() {return rootPath;}public void setRootPath(String rootPath) {this.rootPath = rootPath;}}

package test;import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.ZipEntry;import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream;
import org.apache.commons.compress.parallel.InputStreamSupplier;
import org.apache.commons.io.input.NullInputStream;
import org.junit.Test;public class ScatterSampleTest {@Testpublic void testSample() throws Exception {long begin = System.currentTimeMillis();final File result = new File("d:/test2/eclipse2.zip");createZipFile("F:/Java/eclipseplusUIx64_best", result);long end = System.currentTimeMillis();System.out.println("用时：" + (end - begin) + " ms");}class CustomInputStreamSupplier implements InputStreamSupplier {private File currentFile;public CustomInputStreamSupplier(File currentFile) {this.currentFile = currentFile;}@Overridepublic InputStream get() {try {// InputStreamSupplier api says:// 返回值：输入流。永远不能为Null,但可以是一个空的流return currentFile.isDirectory() ? new NullInputStream(0) : new FileInputStream(currentFile);} catch (FileNotFoundException e) {e.printStackTrace();}return null;}}private void addEntry(String entryName, File currentFile, ScatterSample scatterSample) throws IOException {ZipArchiveEntry archiveEntry = new ZipArchiveEntry(entryName);archiveEntry.setMethod(ZipEntry.DEFLATED);final InputStreamSupplier supp = new CustomInputStreamSupplier(currentFile);scatterSample.addEntry(archiveEntry, supp);}private void compressCurrentDirectory(File dir, ScatterSample scatterSample) throws IOException {if (dir == null) {throw new IOException("源路径不能为空！");}String relativePath = "";if (dir.isFile()) {relativePath = dir.getName();addEntry(relativePath, dir, scatterSample);return;}// 空文件夹if (dir.listFiles().length == 0) {relativePath = dir.getAbsolutePath().replace(scatterSample.getRootPath(), "");addEntry(relativePath + File.separator, dir, scatterSample);return;}for (File f : dir.listFiles()) {if (f.isDirectory()) {compressCurrentDirectory(f, scatterSample);} else {relativePath = f.getParent().replace(scatterSample.getRootPath(), "");addEntry(relativePath + File.separator + f.getName(), f, scatterSample);}}}private void createZipFile(final String rootPath, final File result) throws Exception {File dstFolder = new File(result.getParent());if (!dstFolder.isDirectory()) {dstFolder.mkdirs();}File rootDir = new File(rootPath);final ScatterSample scatterSample = new ScatterSample(rootDir.getAbsolutePath());compressCurrentDirectory(rootDir, scatterSample);final ZipArchiveOutputStream zipArchiveOutputStream = new ZipArchiveOutputStream(result);scatterSample.writeTo(zipArchiveOutputStream);zipArchiveOutputStream.close();}
}

以解压后的eclipse文件为例，用时：4624 ms。比较了一下网上其他的方法，快了2倍多。这结果还算满意。 代码水平有限，只能到这儿了。如果有更精简的代码，欢迎指教。