package io;
import com.sun.istack.internal.NotNull;
import com.sun.istack.internal.Nullable;
import java.io.*;
import java.nio.charset.StandardCharsets;
public class iodemo {
public static void main(String[] args)throws IOException {
String src = "D:\\workspace\\javahmac\\leetcode\\io\\test1.txt";
String dest= "D:\\workspace\\javahmac\\leetcode\\io\\test2.txt";
// readThenWrite(src,dest);
bufferWrite(src,dest);
}
static String readMethod(@NotNull String path) throws IOException {
/** Return string */
InputStream in = new FileInputStream(path);
byte [] bytes = new new byte [1024]; // TODO ONETIME Read bytes length !!!
int num = 0;
// TODO -1 indicates the file pointer to the end of the file, the file is returned on behalf of other num current pointer position, OFF offset indicates the byte array storage
// read () * @ returns the total number of bytes read into the buffer, or
@ -1 indicates if the end since there is no more data, the stream has been reached.
StringBuilder builder = new StringBuilder (); // String str = ""; may be
the while (! (NUM = in.read (bytes, 0, bytes.length)) = -. 1) {
// new new String STR + = ( bytes, 0, num); can
builder.append (new string (bytes, 0 , num)); // number of bytes is converted to a string, line breaks, etc. reserved
}
System.out.println (Builder); // todo with newline
return builder.toString ();
}
@Deprecated
static void writeMethod (path String, String Nullable @ MODE, String text) throws IOException {
/ ** Write bytes [] to File * /
byte[] content = text.getBytes();
if(mode.equals("w")){
OutputStream out =new FileOutputStream(path,false); // w
out.write(content);
}
if(mode.equals("a")){
OutputStream out =new FileOutputStream(path,true); // true 追加写 a+
out.write(content);
}
}
/** onetime r onetime w */
static void readThenWrite(String src,String dest) throws IOException {
InputStream in = new FileInputStream(src); //todo append可以追加，如果dest不存在自动创建；
OUT = new new a FileOutputStream the OutputStream (dest);
// TODO disposable take many bytes
byte [] bytes = new new byte [1024];
// read the file (byte stream cache)
//todo 文件指针-1表示最后一行
int num ;
the while ((NUM = in.read (bytes, 0, bytes.length))! = -1) {
// TODO byte is read every time a conversion String
String STR = new new String (bytes, 0, NUM) ; // this conversion may be achieved byte string, more practical
System.out.println (STR);
// number of bytes per write todo
out.write (bytes, 0, NUM);
}
// the CLOSE the STREAM
in.close ();
the out.close ();
}
static bufferRead String (String the src) throws a FileNotFoundException, IOException {
byte [ ] bytes = new new byte [2048];
// read content receiving (n represents the data, but is a number)
In = new new BufferedInputStream BufferedInputStream (new new the FileInputStream (the src));
// number of bytes taken todo disposable
int = n--1;
String STR = "";
the while ((n-in.read = (bytes, 0, bytes.length !)) = -1) {
// into a string
STR + = new new string (bytes, 0, n-); // charset UTF-Defaults. 8
//System.out.println(str);
}
in.close ( );
return str.toString ();
}
static void bufferWrite (the src String, String dest) throws IOException {
// read the file (byte stream cache)
BufferedInputStream in BufferedInputStream new new = (new new the FileInputStream (the src));
// write into the corresponding file
BufferedOutputStream The new new BufferedOutputStream The OUT = (new new a FileOutputStream (dest));
// number of bytes taken disposable
byte [] bytes = new byte [2048];
// read content receiving (n represents the data, is simply a digital form)
int = n--1;
// TODO extracted data cycle, length of bytes.length
the while (! (n-in.read = (bytes, 0, bytes.length)) = -1) {
// into a string
string str = new string (bytes, 0, n, StandardCharsets.UTF_8);
System.out.println (STR);
// write documents
out.write (bytes, 0, n-);
}
// clear the cache
out.flush ();
// Close stream
in.close ();
the out.close ();
}
}