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

 import java.nio.file.*;
 import java.nio.channels.ReadableByteChannel;
 import java.io.IOException;
 import java.nio.ByteBuffer;

 public class ReadAString {

   public static void main(String[] args) {

     Path file = Paths.get(System.getProperty("user.home")).resolve("Beginning Java Struff").resolve("charData.txt");
     if(!Files.exists(file)) {
       System.out.println(file + " does not exist. Terminating program.");
       System.exit(1);;
     }

     ByteBuffer buf = ByteBuffer.allocate(50);
     try (ReadableByteChannel inCh = Files.newByteChannel(file)){
       while(inCh.read(buf) != -1) {
         System.out.print("String read: " +
                    ((ByteBuffer)(buf.flip())).asCharBuffer().toString());
         buf.clear();                                                   // Clear the buffer for the next read
       }
       System.out.println("EOF reached.");
     } catch(IOException e) {
       e.printStackTrace();
     }
   }
 }