Java基础之读文件——从文件中读取文本（ReadAString）

控制台程序，使用通道从缓冲区获取数据，读取Java基础之写文件（BufferStateTrace）写入的charData.txt

 1 import java.nio.file.*;
 2 import java.nio.channels.ReadableByteChannel;
 3 import java.io.IOException;
 4 import java.nio.ByteBuffer;
 5 
 6 public class ReadAString {
 7 
 8   public static void main(String[] args) {
 9 
10     Path file = Paths.get(System.getProperty("user.home")).resolve("Beginning Java Struff").resolve("charData.txt");
11     if(!Files.exists(file)) {
12       System.out.println(file + " does not exist. Terminating program.");
13       System.exit(1);;
14     }
15 
16     ByteBuffer buf = ByteBuffer.allocate(50);
17     try (ReadableByteChannel inCh = Files.newByteChannel(file)){
18       while(inCh.read(buf) != -1) {
19         System.out.print("String read: " +
20                    ((ByteBuffer)(buf.flip())).asCharBuffer().toString());
21         buf.clear();                                                   // Clear the buffer for the next read
22       }
23       System.out.println("EOF reached.");
24     } catch(IOException e) {
25       e.printStackTrace();
26     }
27   }
28 }