Java Basics - Print Stream of IO Stream Object (PrintStream and PrintWriter)

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　Author: Yin Zhengjie

1. Characteristics of the print stream

　　There are two print objects, namely the byte print stream (PrintStream) and the character print routine (PrintWriter). The methods of the two print streams are exactly the same. The output destination of the print stream is specified in the construction method. The print stream has the following characteristics:

　　　　1>. This stream is not responsible for the data source, only the data purpose;

　　　　2>.Add functions for other output streams;

　　　　3>. IOException will never be thrown, other exceptions may be thrown;

2. The purpose of the print stream output is the File object

　　If you want the file to input some data as it is, then the print stream is very suitable for you! Let's look at the following cases:

 1 /*
 2 @author :yinzhengjie
 3 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 4 EMAIL:[email protected]
 5 */
 6 
 7 package cn.org.yinzhengjie.note6;
 8 
 9 import java.io.File;
10 import java.io.FileNotFoundException;
11 import java.io.IOException;
12 import java.io.PrintWriter;
13 
14 public class PrintWriterDemo {
15     public static void main(String[] args) throws IOException {
 16          File file = new File("yinzhengjie.txt" );
 17          if (! file.exists()) {
 18              file.createNewFile();
 19          }
 20          // Create character output stream, encapsulate file 
21          PrintWriter pw = new PrintWriter(file);
 22          // Write int data type to file 
23          pw.println(100 );
 24          // Write double data type to file 
25          pw.println(3.14 );
 26          // Write to file Write boolean data type 
27          in pw.println(true );
 28          // Release resources 
29          pw.close();
 30      }
 31 }

3. Print stream copy text file

 1 /*
 2 @author :yinzhengjie
 3 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 4 EMAIL:[email protected]
 5 */
 6 
 7 package cn.org.yinzhengjie.note6;
 8 
 9 import java.io.BufferedReader;
10 import java.io.FileReader;
11 import java.io.FileWriter;
12 import java.io.IOException;
13 import java.io.PrintWriter;
14 
15 public class PrintWriterDemo {
16     public static  void main(String[] args) throws IOException {
 17          // Create a data source object 
18          BufferedReader bfr = new BufferedReader( new FileReader("yinzhengjie.properties" ));
 19          // Create a destination object that needs to be printed 
20          FileWriter fw = new FileWriter("yinzhengjie.backup" );
 21          // Turn on the automatic refresh function, if you want to turn off the automatic refresh, change it to false, or if you don't wear this parameter, the default is to turn off the automatic refresh state 
22          PrintWriter pw = new PrintWriter(fw, true ) ;    
 23          // Start copying 
24          String line =null;
25         while(((line = bfr.readLine() )!= null )) {
26             pw.print(line);
27             pw.println();
28         }
29         //释放资源
30         pw.close();
31         bfr.close();
32         
33         
34     }
35 }

Java Basics - Print Stream of IO Stream Object (PrintStream and PrintWriter)

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