import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class text {

    public static void main(String[] args) throws IOException {
        
        
        
        try {
            String str = "hello Java";
            String s = "d:"+File.separator+"text.txt";
            
            File file = new File(s);
            FileOutputStream ops = new FileOutputStream(file);
            
            byte b[] = str.getBytes();
            for(int i=0;i<b.length;i++) {
                if (i%2==0 && b[i]>=‘a‘ && b[i]<=‘z‘) {
                     b[i]=(byte)(b[i]-32);
                }
            }
            ops.write(b);
            ops.close();
            System.out.println("内容为："+new String(b));
        } catch (FileNotFoundException e) {

            e.printStackTrace();
        }
        
  }
}