android 文件读写

android 文件读写
读取：

public static String _getJsonString(String fileName)

 throws IOException { if ((fileName == null) || fileName.isEmpty()) { return ""; } String retString = ""; FileInputStream fis = null; String state = Environment.getExternalStorageState(); if (state.equals(Environment.MEDIA_MOUNTED)) { File file = new File(Environment.getExternalStorageDirectory() + "/" + fileName + ".json"); if (file.exists()) { fis = new FileInputStream(file); byte[] buffer = new byte[fis.available()]; fis.read(buffer); fis.close(); retString = new String(buffer); } else { } } return retString; }

写：

public static void saveSettingFile(String fileName, String content) {

 FileOutputStream fos = null; String state = Environment.getExternalStorageState(); if (state.equals(Environment.MEDIA_MOUNTED)) { File file = new File(Environment.getExternalStorageDirectory() + "/" + fileName + ".json"); try { fos = new FileOutputStream(file); byte[] buffer = content.getBytes(); fos.write(buffer); fos.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } }

Gson 读写：

public static void saveServerInfo(String fileName, String content) {

 FileOutputStream fos = null; String state = Environment.getExternalStorageState(); if (state.equals(Environment.MEDIA_MOUNTED)) { File file = new File(Environment.getExternalStorageDirectory() + "/" + fileName + ".json"); try { fos = new FileOutputStream(file); byte[] buffer = content.getBytes(); fos.write(buffer); fos.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } } public static ServerInfo getServerInfo(String fileName) throws IOException { ServerInfo serverInfo = new ServerInfo(); if ((fileName == null) || fileName.isEmpty()) { serverInfo = null; return serverInfo; } FileInputStream fis = null; String state = Environment.getExternalStorageState(); if (state.equals(Environment.MEDIA_MOUNTED)) { File file = new File(Environment.getExternalStorageDirectory() + "/" + fileName + ".json"); if (file.exists()) { fis = new FileInputStream(file); byte[] buffer = new byte[fis.available()]; fis.read(buffer); fis.close(); Gson gson = new Gson(); serverInfo = gson.fromJson(new String(buffer), ServerInfo.class); } else { serverInfo = null; } } return serverInfo; }

调用：

public void onSetIPAndPort(View view) {

 ServerInfo serverInfo = new ServerInfo(); try { serverInfo = JsonFileWriteAndRead.getServerInfo("videochat"); } catch (IOException e) { e.printStackTrace(); } //写入ip和端口 String ip = ipSet.getText().toString(); String port = portSet.getText().toString(); serverInfo.setIpString(ip); serverInfo.setPortString(port); Gson gson = new Gson(); if (ip.isEmpty() || port.isEmpty()) { Toast.makeText(this, "地址或端口为空", Toast.LENGTH_SHORT).show(); } else { JsonFileWriteAndRead.saveServerInfo("videochat", gson.toJson(serverInfo)); Toast.makeText(this, "地址和端口已经写入文件", Toast.LENGTH_SHORT).show(); } }

作者：小新110
来源：CSDN
原文：https://blog.csdn.net/cau_eric/article/details/90410761
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