我们需要将 StandardCharsets.UTF_8传递给 InputStreamReader构造函数以从 UTF-8 编码文件中读取数据。

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
public class ReadUTF8Data
{
   public static void main(String[] args)
   {
      try {
         File fileDir = new File("c:\temp\test.txt");

         BufferedReader in = new BufferedReader(
            new InputStreamReader(
                       new FileInputStream(fileDir), "UTF8"));

         String str;

         while ((str = in.readLine()) != null) {
             System.out.println(str);
         }

                 in.close();
         } 
         catch (UnsupportedEncodingException e) 
         {
             System.out.println(e.getMessage());
         } 
         catch (IOException e) 
         {
             System.out.println(e.getMessage());
         }
         catch (Exception e)
         {
             System.out.println(e.getMessage());
         }
   }
}