Zipfile/zipinputstream/zipoutputstream of Java IO

When doing a file operation, the general steps are as follows:

Read operation: To target file new an input stream-> read data-> manipulate data

Write: New to target file a output stream-> call write method write data

Understanding the Java compression technology should first understand the structure of the zip file, the following figure, a zip file contains multiple zipentry, called "entries."

The operation of the zip file is similar to the normal file operation, the only difference is that the zip file has a different data structure, and the zip file is a container containing multiple files. Therefore read and write to the zip file is the document in the container to read and write.

Read operations: New to target zip file a zip input stream-> for each entry, a new file input stream for the entry, read the entry data-> manipulate the data

Write: New to target zip file a zip output stream-> for each entry, a new file output stream for the entry, and then writes the data

Code for read operations:

@Test public
void Runzipinputstream () throws IOException {
	//1. Create a Zip input stream
	zipinputstream Zin = new Zipinputstream (New FileInputStream ("Iotest.zip"));
	ZipEntry ze;
	
	2. Processing entries one
	by one while ((Ze = zin.getnextentry ())!= null) {
		//test: Output Entry information
		System.out.printf ("Entry information: Name%1$b, size%2$d, Compression time%3$d \ n ", Ze.getname (), Ze.getsize (), Ze.gettime ());
		
		3. Operation file Content-output, processing
		fileinputstream fin = new FileInputStream (Ze.getname ());
		byte[] buffer = new byte[4096];
		int Len;
		while (len = fin.read (buffer))!=-1) {
			System.out.print (new String (buffer, 0, Len);}}
		}

Write operation code:

@Test public
void Runzipoutputstream () throws IOException {
	//1. Create a Zip output stream
	zipoutputstream Zos = new Zipoutputstream (New FileOutputStream ("Javaio.rar"));
	
	2. Create and set the entry information
	file F = new file ("Javaio.bmp");
	ZipEntry ze = new ZipEntry (F.getname ());
	Ze.setcomment ("Hello, Zip");
	Ze.setsize (F.length ());
	Ze.settime (F.lastmodified ());
	
	3. Add entry to output stream
	zos.putnextentry (ze);
	
	4. Output
	fileinputstream fin = new FileInputStream (f);
	byte[] buffer = new byte[4096];
	int Len;
	while (len = fin.read (buffer))!=-1) {
		zos.write (buffer, 0, Len);
	}
	Fin.close ();
	
	5. Close Stream
	zos.close ();
}

The above code is to operate on a single file, if you want to compress the entire directory, you need to traverse all the files in the directory.