JAVA对字符串的压缩与解压缩

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;

public class ZipUtils {

/**

* 使用gzip进行压缩
*/
public static String gzip(String primStr) {
if (primStr == null || primStr.length() == 0) {
return primStr;
}

ByteArrayOutputStream out = new ByteArrayOutputStream();

GZIPOutputStream gzip=null;
try {
gzip = new GZIPOutputStream(out);
gzip.write(primStr.getBytes());
} catch (IOException e) {
e.printStackTrace();
}finally{
if(gzip!=null){
try {
gzip.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

return new sun.misc.BASE64Encoder().encode(out.toByteArray());
}

/**
*
* <p>Description:使用gzip进行解压缩</p>
* @param compressedStr
* @return
*/
public static String gunzip(String compressedStr){
if(compressedStr==null){
return null;
}

ByteArrayOutputStream out= new ByteArrayOutputStream();
ByteArrayInputStream in=null;
GZIPInputStream ginzip=null;
byte[] compressed=null;
String decompressed = null;
try {
compressed = new sun.misc.BASE64Decoder().decodeBuffer(compressedStr);
in=new ByteArrayInputStream(compressed);
ginzip=new GZIPInputStream(in);

byte[] buffer = new byte[1024];
int offset = -1;
while ((offset = ginzip.read(buffer)) != -1) {
out.write(buffer, 0, offset);
}
decompressed=out.toString();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (ginzip != null) {
try {
ginzip.close();
} catch (IOException e) {
}
}
if (in != null) {
try {
in.close();
} catch (IOException e) {
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
}
}
}

return decompressed;
}

/**
* 使用zip进行压缩
* @param str 压缩前的文本
* @return 返回压缩后的文本
*/
public static final String zip(String str) {
if (str == null)
return null;
byte[] compressed;
ByteArrayOutputStream out = null;
ZipOutputStream zout = null;
String compressedStr = null;
try {
out = new ByteArrayOutputStream();
zout = new ZipOutputStream(out);
zout.putNextEntry(new ZipEntry("0"));
zout.write(str.getBytes());
zout.closeEntry();
compressed = out.toByteArray();
compressedStr = new sun.misc.BASE64Encoder().encodeBuffer(compressed);
} catch (IOException e) {
compressed = null;
} finally {
if (zout != null) {
try {
zout.close();
} catch (IOException e) {
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
}
}
}
return compressedStr;
}

/**
* 使用zip进行解压缩
* @param compressed 压缩后的文本
* @return 解压后的字符串
*/
public static final String unzip(String compressedStr) {
if (compressedStr == null) {
return null;
}

ByteArrayOutputStream out = null;
ByteArrayInputStream in = null;
ZipInputStream zin = null;
String decompressed = null;
try {
byte[] compressed = new sun.misc.BASE64Decoder().decodeBuffer(compressedStr);
out = new ByteArrayOutputStream();
in = new ByteArrayInputStream(compressed);
zin = new ZipInputStream(in);
zin.getNextEntry();
byte[] buffer = new byte[1024];
int offset = -1;
while ((offset = zin.read(buffer)) != -1) {
out.write(buffer, 0, offset);
}
decompressed = out.toString();
} catch (IOException e) {
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) {
}
}
}
return decompressed;
}
}