文件加锁：
文件加锁机制允许我们同步访问某个作为共享资源的文件。
public class Test {
public static void main(String[] args) throws IOException {
FileOutputStream fos = new FileOutputStream("test.txt");
/*
* 通过tryLock 或者 lock 获得整个文件的FileLock
* tryLock(position, size, shared) 对文件进行部分加锁
*/
FileLock fileLock = fos.getChannel().tryLock();
if (fileLock != null) {
System.out.println("Locked file...");
try {
TimeUnit.MILLISECONDS.sleep(100);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
fileLock.release();
System.out.println("Realased Lock ...");
}
}
}
文件压缩：
GZIP进行简单的压缩解压：
public class Test {
public static void main(String[] args) throws IOException {
BufferedReader in = new BufferedReader(new FileReader("/home/estar/Test/a.java"));
BufferedOutputStream bos = new BufferedOutputStream(new GZIPOutputStream(new FileOutputStream("test.gz",true)));
System.out.println("GZIP 压缩写入文件 。。。");
String s;
while ((s = in.readLine()) != null) {
s += "\n";
bos.write(s.getBytes());
}
in.close(); bos.close();
//InputStreamReader 起到了在字节流与字符流转换的桥梁。。。
System.out.println("GZIP 解压读取文件。。。。");
BufferedReader br = new BufferedReader(new InputStreamReader(new GZIPInputStream(new FileInputStream("test.gz"))));
while ((s = br.readLine()) != null) {
System.out.println(s);
}
}
}
输出：
GZIP 压缩写入文件 。。。
GZIP 解压读取文件。。。。
AAHJKHJKAAHJKHJKAAHJKHJKnixingAAHJKHJKAAHJKHJKAAHJKHJKnixingAAHJKHJKAAHJKHJK
AAHJKHJKnixing
AAHJKHJKAAHJKHJK
AAHJKHJKnixing
AAHJKHJKAAHJKHJK
AAHJKHJKnixing
AAHJKHJKAAHJKHJK
AAHJKHJKnixing
ZIP进行多文件保存：
public class Test {
//这里保存要压缩的文件路径
public static String[] path = {"/home/estar/Test/a.java","/home/estar/Test/b.java","/home/estar/cbian/yyy/main.cpp"};
public static void main(String[] args) throws IOException {
FileOutputStream fos = new FileOutputStream("test.zip");
CheckedOutputStream cos = new CheckedOutputStream(fos, new Adler32());
ZipOutputStream zos = new ZipOutputStream(cos);
BufferedOutputStream bos = new BufferedOutputStream(zos);
for (String p : path) {
//通过ZipEntry 将要压缩的文件的写入压缩文件test.zip
zos.putNextEntry(new ZipEntry(p));
//读出每个要压缩的文件的信息，
BufferedReader br = new BufferedReader(new FileReader(p));
String s;
while ((s = br.readLine()) != null) {
System.out.println("from " + p + "content : " + s);
s += "\n";
bos.write(s.getBytes());
}
br.close();
bos.flush();
}
bos.close();
System.out.println("Checksum : " + cos.getChecksum().getValue());
//读压缩文件
System.out.println("Reading file");
FileInputStream fis = new FileInputStream("test.zip");
CheckedInputStream cis = new CheckedInputStream(fis, new Adler32());
ZipInputStream zis = new ZipInputStream(cis);
BufferedReader br = new BufferedReader(new InputStreamReader(zis));
ZipEntry ze;
while ((ze = zis.getNextEntry()) != null) {
System.out.println("reading ze : " + ze);
String s;
while ((s = br.readLine()) != null) {
System.out.println(s);
}
}
System.out.println("Checksum : " + cis.getChecksum().getValue());
ZipFile zf = new ZipFile("test.zip");
Enumeration e = zf.entries();
while (e.hasMoreElements()){
ZipEntry ze1 = (ZipEntry)e.nextElement();
System.out.println("ze1 : " + ze1);
}
}
}
Java编程思想P566