java代理使用 apache ant实现文件压缩/解压缩

【背景】

近日在研究web邮件下载功能，下载的邮件可以导入foxmail邮件客户端，但是批量下载邮件还需将邮件打成一个压缩包。从网上搜索通过java实现文件压缩、解压缩有很多现成的例子。

【参考代码】（需要下载apache ant.jar包）

import java.io.File;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.taskdefs.Expand;
import org.apache.tools.ant.taskdefs.Zip;
import org.apache.tools.ant.types.FileSet;

public class Zipper {
	public final static String encoding = "GBK";

	// 压缩
	public static void zip(String srcPathname, String zipFilepath)
			throws BuildException, RuntimeException {
		File file = new File(srcPathname);
		if (!file.exists())
			throw new RuntimeException("source file or directory "
					+ srcPathname + " does not exist.");

		Project proj = new Project();
		FileSet fileSet = new FileSet();
		fileSet.setProject(proj);
		// 判断是目录还是文件
		if (file.isDirectory()) {
			fileSet.setDir(file);
			// ant中include/exclude规则在此都可以使用
			// 比如:
			// fileSet.setExcludes("**/*.txt");
			// fileSet.setIncludes("**/*.xls");
		} else {
			fileSet.setFile(file);
		}

		Zip zip = new Zip();
		zip.setProject(proj);
		zip.setDestFile(new File(zipFilepath));
		zip.addFileset(fileSet);
		zip.setEncoding(encoding);
		zip.execute();
	}

	// 解压缩
	public static void unzip(String zipFilepath, String destDir)
			throws BuildException, RuntimeException {
		if (!new File(zipFilepath).exists())
			throw new RuntimeException("zip file " + zipFilepath
					+ " does not exist.");

		Project proj = new Project();
		Expand expand = new Expand();
		expand.setProject(proj);
		expand.setTaskType("unzip");
		expand.setTaskName("unzip");
		expand.setEncoding(encoding);

		expand.setSrc(new File(zipFilepath));
		expand.setDest(new File(destDir));
		expand.execute();
	}
}