我们经常会使用WinZIP等压缩软件将文件进行压缩以方便传输。在java里面也提供了将文件进行压缩以减少传输时的数据量的类，可以很方便的将文件压缩成ZIP、JAR、GZIP等形式，GZIP主要是在Linux系统下的压缩文件。
下面主要讲的就是ZIP形式的压缩文件，而JAR、GZIP形式的压缩文件也是类似的用法。
ZIP是一种很常见的压缩形式，在java中要实现ZIP的压缩主要用到的是java.util.zip这个包里面的类。主要有ZipFile、 ZipOutputStream、ZipInputStream和ZipEntry。ZipOutputStream是用来压缩文件 的，ZipInputStream和ZipFile是用来解压缩文件的，在压缩和解压缩的过程中，ZipEntry都会用到。在java的Zip压缩文件 中，每一个子文件都是一个ZipEntry对象。
压缩文件
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
public class ZipOutputStreamTest {
public static void main(String args[]) throws IOException {
test1();
test2();
}
public static void test1() throws IOException {
ZipOutputStream zos = new ZipOutputStream(new FileOutputStream("D:\\testZip.zip"), Charset.forName("GBK"));
//实例化一个名称为ab.txt的ZipEntry对象
ZipEntry entry = new ZipEntry("ab.txt");
//设置注释
zos.setComment("zip测试for单个文件");
//把生成的ZipEntry对象加入到压缩文件中，而之后往压缩文件中写入的内容都会放在这个ZipEntry对象里面
zos.putNextEntry(entry);
InputStream is = new FileInputStream("D:\\ab.txt");
int len = 0;
while ((len = is.read()) != -1)
zos.write(len);
is.close();
zos.close();
}
public static void test2() throws IOException {
File inFile = new File("D:\\test");
ZipOutputStream zos = new ZipOutputStream(new FileOutputStream("D:\\test.zip"), Charset.forName("GBK"));
zos.setComment("多文件处理");
zipFile(inFile, zos, "");
zos.close();
}
public static void zipFile(File inFile, ZipOutputStream zos, String dir) throws IOException {
if (inFile.isDirectory()) {
File[] files = inFile.listFiles();
for (File file:files)
zipFile(file, zos, dir + "\\" + inFile.getName());
} else {
String entryName = null;
if (!"".equals(dir))
entryName = dir + "\\" + inFile.getName();
else
entryName = inFile.getName();
ZipEntry entry = new ZipEntry(entryName);
zos.putNextEntry(entry);
InputStream is = new FileInputStream(inFile);
int len = 0;
while ((len = is.read()) != -1)
zos.write(len);
is.close();
}
}
}解压缩文件
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import java.util.zip.ZipInputStream;
public class ZipInputStreamTest {
public static void main(String args[]) throws IOException {
File file = new File("D:\\test.zip");//压缩文件
ZipFile zipFile = new ZipFile(file);//实例化ZipFile，每一个zip压缩文件都可以表示为一个ZipFile
//实例化一个Zip压缩文件的ZipInputStream对象，可以利用该类的getNextEntry()方法依次拿到每一个ZipEntry对象
ZipInputStream zipInputStream = new ZipInputStream(new FileInputStream(file), Charset.forName("GBK"));
ZipEntry zipEntry = null;
while ((zipEntry = zipInputStream.getNextEntry()) != null) {
String fileName = zipEntry.getName();
File temp = new File("D:\\unpackTest\\" + fileName);
if (! temp.getParentFile().exists())
temp.getParentFile().mkdirs();
OutputStream os = new FileOutputStream(temp);
//通过ZipFile的getInputStream方法拿到具体的ZipEntry的输入流
InputStream is = zipFile.getInputStream(zipEntry);
int len = 0;
while ((len = is.read()) != -1)
os.write(len);
os.close();
is.close();
}
zipInputStream.close();
}
}下面的是apache的解压缩包
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import org.apache.tools.zip.ZipEntry;
import org.apache.tools.zip.ZipFile;
/**
* 可以处理中文文件名
*/
public class UnZip2
{
private static final int buffer = 2048;
public static void main(String[] args)
{
unZip("D:\\ss\\test.zip");
}
public static void unZip(String path)
{
int count = -1;
int index = -1;
String savepath = "";
boolean flag = false;
File file = null;
InputStream is = null;
FileOutputStream fos = null;
BufferedOutputStream bos = null;
savepath = path.substring(0, path.lastIndexOf("\\")) + "\\";
try
{
ZipFile zipFile = new ZipFile(path);
Enumeration<?> entries = zipFile.getEntries();
while(entries.hasMoreElements())
{
byte buf[] = new byte[buffer];
ZipEntry entry = (ZipEntry)entries.nextElement();
String filename = entry.getName();
index = filename.lastIndexOf("/");
if(index > -1)
filename = filename.substring(index+1);
filename = savepath + filename;
flag = isPics(filename);
if(!flag)
continue;
file = new File(filename);
file.createNewFile();
is = zipFile.getInputStream(entry);
fos = new FileOutputStream(file);
bos = new BufferedOutputStream(fos, buffer);
while((count = is.read(buf)) > -1)
{
bos.write(buf, 0, count );
}
fos.close();
is.close();
}
zipFile.close();
}catch(IOException ioe){
ioe.printStackTrace();
}
}
public static boolean isPics(String filename)
{
boolean flag = false;
if(filename.endsWith(".jpg") || filename.endsWith(".gif") || filename.endsWith(".bmp") || filename.endsWith(".png"))
flag = true;
return flag;
}
}
