Other Useful Methodes
Other Useful Methodes
Determining MIME Type
ContentType.java
import java.nio.file.*;
import java.io.*;
public class ContentType {
public static void main(String[] args) {
Path filename = Paths.get("ContentType.class");
try {
String type = Files.probeContentType(filename);
if (type == null) {
System.err.format("'%s' has an" + " unknown filetype.%n", filename);
} else if (!type.equals("text/plain")) {
System.err.format("'%s' is not" + " a plain text file.%n", filename);
}
} catch (IOException x) {
System.err.println(x);
}
}
}
Default File System
DefaultFile.java
import java.nio.file.*;
public class DefaultFile {
public static void main(String[] args) {
Path name = Paths.get("Format.java").getFileName();
PathMatcher matcher = FileSystems.getDefault().getPathMatcher("glob:*.java");
if (matcher.matches(name)) {
System.out.println(name + " match right");
}
}
}
Path String Separator
PathSeparator.java
import java.nio.file.*;
import java.io.*;
public class PathSeparator {
public static void main(String[] args) {
String separator = File.separator;
System.out.println("separator: " + separator);
separator = FileSystems.getDefault().getSeparator();
System.out.println("separator: " + separator);
}
}
File System’s File Stores
Main2.java
import java.nio.file.*;
import java.io.*;
public class Main2 {
public static void main(String[] args) throws IOException {
for (FileStore store: FileSystems.getDefault().getFileStores()) {
long total = store.getTotalSpace() / 1024;
System.out.println("file store name: " + store.name() + "total: " + total);
// long used = (store.getTotalSpace() - store.getUnallocatedSpace()) / 1024;
// long avail = store.getUsableSpace() / 1024;
// System.out.format("%-20s %12d %12d %12dn", store, total, used, avail);
}
}
}
Main3.java
import java.nio.file.*;
import java.io.*;
public class Main3 {
public static void main(String[] args) throws IOException {
Path file = Paths.get("Format.java");
FileStore store = Files.getFileStore(file);
long total = store.getTotalSpace() / 1024;
System.out.println("file store name: " + store.name() + " total: " + total);
}
}
example
DiskUsage.java
/*
* Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of Oracle nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
import java.nio.file.*;
import java.nio.file.attribute.*;
import java.io.IOException;
/**
* Example utility that works like the df(1M) program to print out disk space
* information
*/
public class DiskUsage {
static final long K = 1024;
static void printFileStore(FileStore store) throws IOException {
long total = store.getTotalSpace() / K;
long used = (store.getTotalSpace() - store.getUnallocatedSpace()) / K;
long avail = store.getUsableSpace() / K;
String s = store.toString();
if (s.length() > 20) {
System.out.println(s);
s = "";
}
System.out.format("%-20s %12d %12d %12d\n", s, total, used, avail);
}
public static void main(String[] args) throws IOException {
System.out.format("%-20s %12s %12s %12s\n", "Filesystem", "kbytes", "use ", "avail");
if (args.length == 0) {
FileSystem fs = FileSystems.getDefault();
for (FileStore store: fs.getFileStores()) {
printFileStore(store);
}
} else {
for (String file: args) {
FileStore store = Files.getFileStore(Paths.get(file));
printFileStore(store);
}
}
}
}