java怎样把一字符串数组写入.txt文件中？

import java.io.File;
import java.io.OutputStream;
import java.io.FileOutputStream;
public class TestFile {
public static void main(String[] args) throws Exception{
//在d盘上创建一个名为testfile的文本文件
File f = new File("D:"+File.separator+"testfile.txt");
//用FileOutputSteam包装文件，并设置文件可追加
OutputStream out = new FileOutputStream(f,true);
//字符数组
String[] str = {"shanghai","beijing","guangdong","xiamen"};
for(int i =0; i out.write(str[i].getBytes()); //向文件中写入数据
out.write('\r'); // \r\n表示换行
out.write('\n');
}
out.close(); //关闭输出流
System.out.println("写入成功！");
}

}