android 读取内部存储文件格式 android读取文本文件

在android或者java中读写文件时，我们常常面临不知道该用哪种方法来实现，今天我们一起来总结一下N种读写文件的方法。

一、文件输入输出流读写文件

public void writeFileString(File file, String str){
        if(file.canWrite()){
            try {
                FileOutputStream fileOutputStream = new FileOutputStream(file);
                fileOutputStream.write(str.getBytes());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }else {
            Log.e(TAG, "No permission to write file.");
        }
    }



    public String readFileString(File file){
        String str = "";
        if(file.canRead()){
            try {
                FileInputStream fileInputStream = new FileInputStream(file);
                int length = fileInputStream.available();
                byte[] bytes = new byte[length];
                fileInputStream.read(bytes);
                str = new String(bytes);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return str;
    }

二、BufferWriter读写文件

public void writeFileString(String file, String str){
        File file1 = new File(file);
        if(file1.canWrite()){
            try {
                BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(file));
                bufferedWriter.write(str);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }


    public String readFileString(String file){
        File file1 = new File(file);
        char[] buf = new char[512];
        StringBuilder stringBuilder = new StringBuilder();
        int length=0;
        if(file1.canWrite()){
            try {
                BufferedReader bufferedReader = new BufferedReader(new FileReader(file));
                while((length = bufferedReader.read(buf)) != -1){
                    stringBuilder.append(buf);
                }
                bufferedReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return stringBuilder.toString();
    }

BufferWriter和BufferReader实际上就是对FileOutputStream和FileInputStream的标准化封装