输出流：将内存中的数据写入到磁盘文件中，防止中文乱码，需要指定writer的字符集
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(“D:\\test.txt”,true,”UTF-8″)));
writer.write(“我是中文”);
输入流：将磁盘文件读入内存，防止中文乱码，需指定输入流reader的字符集
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(“D:\\test.txt”),”UTF-8″))
String s = null;
StringBuilder sb = new StringBuilder();
while(s = reader.readLine() != null){
sb.append(s);
}
如果需要保留文本中的：\r\n 则不能使用BufferedReader
InputStreamReader reader = new InputStreamReader(new FileInputStream(“D:\\test.txt”),”UTF-8″);
StringBuilder sb = new StringBuilder();
byte [] buff = new byte[2048];
int length = 0;
while(-1 != (length = reader.read(buff))){
sb.append(new String(buff,0,length));
}