java 写入文件编码“UTF-8”问题

Question

写入文件希望是“UTF-8”编码，参考了网上的方法，但是得到文件还都是“ANSI”编码。
请帮忙看看问题出在哪里？
还有其他方法设置写入文件编码是“UTF-8”么？

代码如下：

public void bufferedWriterTest01() throws IOException
    {
        File file=new File("test01.txt");
        FileOutputStream fileOutputStream=new FileOutputStream(file);
        OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fileOutputStream, "UTF-8");  //设置编码
        BufferedWriter bufferedWriter=new BufferedWriter(outputStreamWriter);

        String[] str= {"nihao","shuxue","yuwen","woshi","shui","alisdfk"};
        for (int i = 0; i < str.length; i++)
        {
            bufferedWriter.write( str[i]); 
            bufferedWriter.newLine();
        }

        bufferedWriter.close();
        outputStreamWriter.close();
        fileOutputStream.close();
    
        System.out.println(“End");        
    }

Answer 1

得到的文件是用什么打开的？
Idea的编码是什么？