java读取txt时出现乱码 - Java / Java SE

就是一个很简单的小程序，要读入txt中的文本。程序如下：

package lesson;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;


public class c {
static String str;

static char[] charnum=new char[1024];
static int i=0;
 
public static void main(String[] args) {
File aFile = new File("D:/Java/example.txt");
FileInputStream inFile = null;
 
try {
inFile = new FileInputStream(aFile); 

} catch(FileNotFoundException e) {
e.printStackTrace(System.err);
System.exit(1);
}
 
FileChannel inChannel = inFile.getChannel();  
ByteBuffer buf = ByteBuffer.allocate(1024);  
try {
 
  while(inChannel.read(buf) != -1) {
str= ((ByteBuffer)(buf.flip())).asCharBuffer().toString();
  System.out.println(str);  
  System.out.println(new String(str.getBytes(),"UTF-8"));  
buf.clear();
}  
inFile.close();  
} catch(IOException