android文件读写-创新互联

• 在sd卡中读写

1. 文件路径

//sd卡的路径
private static final String SD_PATH = Environment
            .getExternalStorageDirectory()+"//notes";
private static final String FILE_NAME="note";

2. 检查文件是否存在

public static void checkDir(){File fileDir=new File(SD_PATH);
        if(!fileDir.exists()){fileDir.mkdirs();

        }
    }

3. 读取文件

public static Listread(Context context){  //  String fileName="innerFile";
        checkDir();
        FileInputStream fis=null;
        StringBuilder builder=null;
        try {  //      fis=context.openFileInput(fileName);
           fis=new FileInputStream(new File(SD_PATH,FILE_NAME));

            BufferedReader bf=new BufferedReader(new InputStreamReader(fis));
            builder=new StringBuilder();
            String line=null;
            while((line=bf.readLine())!=null){builder.append(line);
            }
            } catch (IOException e) {e.printStackTrace();
            } finally {if (fis != null) {try {fis.close();
                    } catch (IOException e) {e.printStackTrace();
                    }

                }
            }
        //使用gson将json字符串转成list
        Gson gson=new Gson();
        return gson.fromJson(datalist,new TypeToken>(){}.getType());
    }

4. 写入文件

public static void write(Listlist, Context context){  //  String fileName="innerFile";
        checkDir();
        Gson gson=new Gson();
        String outData = gson.toJson(list);
        FileOutputStream fos=null;
        try {  //  fos=context.openFileOutput(fileName, Context.MODE_PRIVATE);
            fos=new FileOutputStream(new File(SD_PATH,FILE_NAME));
            if(outData!=null){fos.write(outData.getBytes());
            }
            fos.flush();
        } catch (IOException e) {e.printStackTrace();
        } finally {if(fos!=null){try {fos.close();
                } catch (IOException e) {e.printStackTrace();
                }
            }
        }

    }

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