The flow object selection rules in java programming are explained in detail
- 2020-05-30 20:03:14
- OfStack
Examples are as follows:
import java.io.*;
public class TransStreamDemo2 {
/**
* Basic rules of flow operation *
1 ,
* Source, keyboard entry
* Purpose. The console
* 2 ,
* Requirements: want to store keyboard input data to 1 In a file.
* Source: the keyboard
* Purpose: document ( FileoutputStream Can manipulate files)
* 3 ,
* Need: want to take 1 The data of the file is printed to the console
* Source: a file
* Purpose: console
*
*
* Basic rules of flow operation
* The most painful thing is that many stream objects do not know which to use
*
* This is done with two unambiguities
* 1 , source and destination.
*
Source: input stream, InputStream Reader
*
Purpose: output stream OutputStream Writer
* 2 , whether the data of operation is plain text
* is : Characters of the flow Reader Writer
* No: byte stream InputStreamReader OutputStreamWriter
* 3 , when the system is clear then clear to use that specific object
*
Distinguish by device
*
Source device: hard disk memory The keyboard
*
Destination device: hard disk memory The console
*
*
* 1 Will, 1 Save the data in the file to another 1 In a file. Copy the file
*
Source: a read stream is used because it is a source. InputStream Reader
*
Do not operate text file: yes choose Reader
* So the system is clear
* The next step is to specify which objects the system will use
* Clear device: hard disk On the 1 A file
* Reader The objects in the system that can manipulate files are FileReader
*
*
* Objective: OutputStreamWriter Whether plain text or not
* Is this: Writer
* Equipment: hard disk 1 A file
* Writer The objects in the system that can manipulate files are FileReader
*
* FileReader fr=new FileReader("a.txt");
* If efficiency is improved: BufferedReader bufr=new BufferedReader(fr);
*
*
FilrWriter fw=new FileWriter("b.txt");
* Whether to improve efficiency: BufferedWriter fw=new BufferedWriter(fw);
*
* */
public static void main(String[] args) throws IOException{
// TODO Auto-generated method stub
BufferedReader bufr=new BufferedReader(new InputStreamReader(new FileInputStream("d://wdl.txt")));
//
BufferedWriter bufw=new BufferedWriter(new OutputStreamWriter(new FileOutputStream("d://wdl.txt")));
BufferedWriter bufw=new BufferedWriter(new OutputStreamWriter(System.out));
String line=null;
while((line=bufr.readLine())!=null){
if("over".equals(line))
break;
bufw.write(line.toUpperCase());
bufw.newLine();
//
System.out.println(line.toUpperCase());
bufw.flush();
}
bufr.close();
bufw.close();
}
}