用Java代码实现文件的压缩

从网上找的一些别人写的代码，自己重新写了一下。这是Java自带的不支持中文。密码暂时只支持三个字符的密码。

如果要实现中文格式的文档压缩解压缩就要用

import org.apache.tools.zip.ZipEntry;

import org.apache.tools.zip.ZipOutputStream;

来替换。这是ant.jar中的。

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Random;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;

public class Zip {
private static final int SIZE = 1024;
private static final String algorithm = "PBEWithMD5AndDES";

public void compressing(File from, File to) throws Exception {
compressAndPwd(from, to, null);
}

public void compressAndPwd(File from, File to, String pwd) throws Exception {
ZipOutputStream zipOutputStream = new ZipOutputStream(new FileOutputStream(to));
BufferedOutputStream toOut = new BufferedOutputStream(zipOutputStream, SIZE);
compressing(zipOutputStream, from, from.getName(), toOut, pwd);
zipOutputStream.close();
toOut.close();
}

public void compressing(ZipOutputStream zipOutputStream, File from, String base, BufferedOutputStream toOut, String pwd) throws Exception {
if (from.isDirectory()) {
zipOutputStream.putNextEntry(new ZipEntry(base + "/"));
File[] files = from.listFiles();
if (files.length == 0) {
base = "";
} else {
base += "/";
}
for (int i = 0; i < files.length; i++) {
compressing(zipOutputStream, files[i], base + files[i].getName(), toOut, pwd);
}
zipOutputStream.closeEntry();
} else {
zipOutputStream.putNextEntry(new ZipEntry(base));
FileInputStream in = new FileInputStream(from);
BufferedInputStream bis = new BufferedInputStream(in);
if (pwd == null) {
System.out.println(base);
System.out.println(from.length());
int len = -1;
while ((len = bis.read()) != -1) {
toOut.write(len);
}
toOut.flush();
} else {
ex(zipOutputStream, pwd, in);
}
bis.close();
in.close();
zipOutputStream.closeEntry();
}
}

public void decompress(File zipFile, File outFile) throws Exception {
decompress(zipFile, outFile, null);
}

public void decompress(File zipFile, File outFile, String pwd) throws Exception {
// TODO Auto-generated method stub
long startTime = System.currentTimeMillis();
if (outFile.exists() && outFile.isDirectory()) {
outFile.mkdirs();
}
ZipInputStream zis = new ZipInputStream(new FileInputStream(zipFile));// 输入源zip路径
BufferedInputStream bis = new BufferedInputStream(zis);

ZipEntry entry = null;//<span style="color:#ff0000;">用ant的时候要用<span style="font-family: Arial, Helvetica, sans-serif;">java.util.zip.</span><span style="font-family: Arial, Helvetica, sans-serif;">ZipEntry</span></span>
while ((entry = zis.getNextEntry()) != null) {
if (entry.isDirectory()) {
String nameString = entry.getName();
nameString = nameString.substring(0, nameString.length() - 1);
File file = new File(outFile.getAbsolutePath() + File.separator + nameString);
if (!file.exists()) {
file.mkdirs();
}
} else {
System.out.println(outFile.getAbsolutePath() + File.separator + entry.getName());
File file = new File(outFile.getAbsolutePath() + File.separator + entry.getName());
file.createNewFile();
FileOutputStream fos = new FileOutputStream(file);
BufferedOutputStream bos = new BufferedOutputStream(fos);
if (pwd == null) {
int len = -1;
while ((len = bis.read()) != -1) {
bos.write(len);
}
bos.flush();
} else {
decompressAndPwd(zis, fos, pwd);
}
bos.close();
fos.close();
System.out.println(file.getName() + "解压成功");
}
}
bis.close();
zis.close();
long endTime = System.currentTimeMillis();
System.out.println("耗费时间： " + (endTime - startTime) + " ms");
}

public void ex(ZipOutputStream bos, String pwd, FileInputStream bis) throws Exception {
PBEKeySpec keySpec = new PBEKeySpec(pwd.toCharArray());
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(algorithm);
SecretKey passwordKey = keyFactory.generateSecret(keySpec);
byte[] salt = new byte[8];
Random rnd = new Random();
rnd.nextBytes(salt);
int iterations = 100;
PBEParameterSpec parameterSpec = new PBEParameterSpec(salt, iterations);
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(Cipher.ENCRYPT_MODE, passwordKey, parameterSpec);
bos.write(salt);
byte[] input = new byte[64];
int bytesRead;
while ((bytesRead = bis.read(input)) != -1) {
byte[] output = cipher.update(input, 0, bytesRead);
if (output != null) {
bos.write(output);
}
}
byte[] output = cipher.doFinal();
if (output != null) {
bos.write(output);
}
bos.flush();
}

public void decompressAndPwd(ZipInputStream bis, FileOutputStream bos, String pwd) throws Exception {
PBEKeySpec keySpec = new PBEKeySpec(pwd.toCharArray());
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(algorithm);
SecretKey passwordKey = keyFactory.generateSecret(keySpec);
byte[] salt = new byte[8];
bis.read(salt);
int iterations = 100;
PBEParameterSpec parameterSpec = new PBEParameterSpec(salt, iterations);
Cipher cipher = Cipher.getInstance(algorithm);
cipher.init(Cipher.DECRYPT_MODE, passwordKey, parameterSpec);
byte[] input = new byte[64];
int bytesRead;
while ((bytesRead = bis.read(input)) != -1) {
byte[] output = cipher.update(input, 0, bytesRead);
if (output != null) {
bos.write(output);
}
}
byte[] output = cipher.doFinal();
if (output != null) {
bos.write(output);
}
bos.flush();
}

}