读文件
```
String FILE_PATH = Environment.getExternalStorageDirectory().getPath() + "/a.text" ;
FileInputStream fis = new FileInputStream(FILE_PATH);
BufferedReader br = new BufferedReader(new InputStreamReader(fis, "UTF-8"));
String readLine = "";
StringBuffer sb = new StringBuffer();
while ((readLine = br.readLine()) != null) {
sb.append(readLine);
}
br.close();
```
写文件
```
try {
File file = new File(FILE_PATH);
OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(file), "UTF-8");
String jsonString = JSONUtils.getJsonString(musicInfos);
writer.write(jsonString);
writer.flush();
showMsg("写入成功");
} catch (Exception e) {
e.printStackTrace();
showMsg("写入失败");
}
```
File类常用操作
```
String Name = File.getName(); //获得文件或文件夹的名称：
String parentPath = File.getParent(); //获得文件或文件夹的父目录
String path = File.getAbsoultePath();//绝对路经
String path = File.getPath();//相对路经
File.createNewFile();//建立文件
File.mkDir(); //建立文件夹
File.isDirectory(); //判断是文件或文件夹
File[] files = File.listFiles(); //列出文件夹下的所有文件和文件夹名
File.renameTo(dest); //修改文件夹和文件名
File.delete(); //删除文件夹或文件
