java数据流压缩

package com.wfy.util;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;

public class DataCompression {
	/**
	 * 压缩字符串为 byte[] 储存可以使用new sun.misc.BASE64Encoder().encodeBuffer(byte[] b)方法
	 * 保存为字符串
	 * 
	 * @param str
	 *            压缩前的文本
	 * @return
	 */
	public static final byte[] compress(Object obj) {
		System.out.println("压缩字节开始：" + TimeUtil.dateTime1());
		if (obj == null)
			return null;

		byte[] compressed;
		ByteArrayOutputStream out = null;
		ZipOutputStream zout = null;

		try {
			out = new ByteArrayOutputStream();
			zout = new ZipOutputStream(out);
			zout.putNextEntry(new ZipEntry("0"));
			ByteArrayOutputStream out1 = new ByteArrayOutputStream();
			ObjectOutputStream oos = new ObjectOutputStream(out1);
			oos.writeObject(obj);
			byte[] bytes = out1.toByteArray();
			zout.write(bytes);
			zout.closeEntry();
			compressed = out.toByteArray();
		} catch (IOException e) {
			e.printStackTrace();
			compressed = null;
		} finally {
			if (zout != null) {
				try {
					zout.close();
				} catch (IOException e) {
				}
			}
			if (out != null) {
				try {
					out.close();
				} catch (IOException e) {
				}
			}
		}
		System.out.println("压缩字节结束：" + TimeUtil.dateTime1());
		return compressed;
	}

	/**
	 * 将压缩后的 byte[] 数据解压缩
	 * 
	 * @param compressed
	 *            压缩后的 byte[] 数据
	 * @return 解压后的字符串
	 * @throws ClassNotFoundException 
	 */
	public static final Object decompress(byte[] compressed) {
		System.out.println("解压字节开始：" + TimeUtil.dateTime1());
		if (compressed == null)
			return null;

		ByteArrayOutputStream out = null;
		ByteArrayInputStream in = null;
		ZipInputStream zin = null;
		Object decompressed;
		try {
			out = new ByteArrayOutputStream();
			in = new ByteArrayInputStream(compressed);
			zin = new ZipInputStream(in);
			ZipEntry entry = zin.getNextEntry();
			byte[] buffer = new byte[1024];
			int offset = -1;
			while ((offset = zin.read(buffer)) != -1) {
				out.write(buffer, 0, offset);
			}
			
			ByteArrayInputStream in1 = new ByteArrayInputStream(out.toByteArray());
			ObjectInputStream ois = new ObjectInputStream(in1);
			decompressed = ois.readObject();
		} catch (Exception e) {
			e.printStackTrace();
			decompressed = null;
		} finally {
			if (zin != null) {
				try {
					zin.close();
				} catch (IOException e) {
				}
			}
			if (in != null) {
				try {
					in.close();
				} catch (IOException e) {
				}
			}
			if (out != null) {
				try {
					out.close();
				} catch (IOException e) {
				}
			}
		}
		System.out.println("解压字节结束：" + TimeUtil.dateTime1());
		return decompressed;
	}
}

 

评论

2 楼 JasonShieh 2011-04-08  

测试了一下，发现越压缩越大。93个字节压到135个字节，不知道是不是我哪里搞错了

1 楼 fllbai 2010-04-05  

这正是我需要的，thanks