Android studio 파일 지정 문자열 추출

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /><!--       -->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /><!--       -->

       new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    //    
                    InputStreamReader isr = new InputStreamReader(new FileInputStream("    "), "UTF8");//UTF8  
                    BufferedReader br = new BufferedReader(isr);
                    String text = br.readLine();
                    String str = "";
                    while ((str = br.readLine()) != null) {
                        str += "";
                        //    
                        if (str != null) {
                            str.contains("xx");
                            String str_1 = str.substring(str.indexOf("x")+1,str.indexOf(".")+2);
                      
outputToFile("test2.txt",str_1+"
");//         ，      ，    。
                        }
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();

    public void outputToFile(String file_name, String txt)	//file_name =    , txt =    {
        try {
            FileOutputStream outSTr = new FileOutputStream(new File("     "+file_name), true);
            BufferedOutputStream Buff = new BufferedOutputStream(outSTr);
            Buff.write(txt.getBytes());
            Buff.flush();
            Buff.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }