JAva nioインスタンス1
JAva nioの例
public class NewIOChannel {
private String file = "";
private String file2 = "";
@Before
public void init(){
file = NewIOChannel.class.getResource("").getPath()+"\\myfile.txt";
file2 = NewIOChannel.class.getResource("").getPath()+"\\myfile2.txt";
System.out.println(file);
}
/**
* outputStream channel
* @throws IOException
*/
@Test
public void FileTest() throws IOException{
String info[] = {"wang","fwefwe"," "};
File file = new File(this.file);
FileOutputStream output = null;
output = new FileOutputStream(file);
FileChannel fout = null;
fout = output.getChannel();
ByteBuffer buf = ByteBuffer.allocate(1024);
for (int i = 0; i < info.length; i++) {
buf.put(info[i].getBytes("UTF-8"));
}
buf.flip();
fout.write(buf);
fout.close();
output.close();
}
@Test
public void writeFile()throws IOException{
File file = new File(this.file);
FileInputStream input = new FileInputStream(file);
FileChannel fileChannel = input.getChannel();
byte data[] = new byte[(int)file.length()];
// MappedByteBuffer mbb = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, file.length());
// int foot = 0;
// while(mbb.hasRemaining())
// data[foot++] = mbb.get();
ByteBuffer bufs = ByteBuffer.wrap(data);
fileChannel.read(bufs);
System.out.println(new String(data));
fileChannel.close();
}
@Test
public void writereadFile() throws IOException{
File file = new File(this.file);
File file2 = new File(this.file2);
FileInputStream input = new FileInputStream(file);
FileOutputStream output = new FileOutputStream(file2);
FileChannel fout = output.getChannel();
FileChannel fin = input.getChannel();
ByteBuffer buf = ByteBuffer.allocate(1024);
int temp =0;
while ((temp = fin.read(buf)) != -1) {
buf.flip();
fout.write(buf);
buf.clear();
}
fin.close();
fout.close();
}
@Test
public void FileLockDemo() throws IOException, InterruptedException{
File file = new File(this.file);
FileOutputStream output = new FileOutputStream(file,true);
FileChannel fout = output.getChannel();
FileLock lock = fout.tryLock();
if(lock != null){
System.out.println(file.getName()+" 5 ");
Thread.sleep(5000);
lock.release();
System.out.println(file.getName()+" ");
}
fout.close();
output.close();
}
}