java解压,压缩.gz文件
/*
* gz文件是linux下常见的压缩格式。使用 java.util.zip.GZIPInputStream即可,压缩是 java.util.zip.GZIPOutputStream
*/
压缩为.gz文件
java代码如下,经本地测试未发现问题。
public static void compressFile(String inFileName) {
String outFileName = inFileName+ ".gz";
FileInputStream in = null;
try {
in = new FileInputStream(new File(inFileName));
}catch (FileNotFoundException e) {
System.out.println("Could not find the inFile..."+inFileName);
}
GZIPOutputStream out = null;
try {
out = new GZIPOutputStream(new FileOutputStream(outFileName));
}catch (IOException e) {
System.out.println("Could not find the outFile..."+outFileName);
}
byte[] buf = new byte[10240];
int len = 0;
try {
while (((in.available()>10240)&& (in.read(buf)) > 0)) {
out.write(buf);
}
len = in.available();
in.read(buf, 0, len);
out.write(buf, 0, len);
in.close();
System.out.println("Completing the GZIP file..."+outFileName);
out.flush();
out.close();
}catch (IOException e) {
}
}
解压.gz文件,本地测试通过
public static void doUncompressFile(String inFileName) {
try {
if (!getExtension(inFileName).equalsIgnoreCase("gz")) {
System.err.println("File name must have extension of \".gz\"");
System.exit(1);
}
System.out.println("Opening the compressed file.");
GZIPInputStream in = null;
try {
in = new GZIPInputStream(new FileInputStream(inFileName));
} catch(FileNotFoundException e) {
System.err.println("File not found. " + inFileName);
System.exit(1);
}
System.out.println("Open the output file.");
String outFileName = getFileName(inFileName);
FileOutputStream out = null;
try {
out = new FileOutputStream(outFileName);
} catch (FileNotFoundException e) {
System.err.println("Could not write to file. " + outFileName);
System.exit(1);
}
System.out.println("Transfering bytes from compressed file to the output file.");
byte[] buf = new byte[1024];
int len;
while((len = in.read(buf)) > 0) {
out.write(buf, 0, len);
}
System.out.println("Closing the file and stream");
in.close();
out.close();
} catch (IOException e) {
e.printStackTrace();
System.exit(1);
}
}
/**
* Used to extract and return the extension of a given file.
* @param f Incoming file to get the extension of
* @return <code>String</code> representing the extension of the incoming
* file.
*/
public static String getExtension(String f) {
String ext = "";
int i = f.lastIndexOf('.');
if (i > 0 && i < f.length() - 1) {
ext = f.substring(i+1);
}
return ext;
}
/**
* Used to extract the filename without its extension.
* @param f Incoming file to get the filename
* @return <code>String</code> representing the filename without its
* extension.
*/
public static String getFileName(String f) {
String fname = "";
int i = f.lastIndexOf('.');
if (i > 0 && i < f.length() - 1) {
fname = f.substring(0,i);
}
return fname;
}
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