追加文件会导致覆盖（Java）

Question

因此，我创建了一个CSV文件，每次发生一个操作时，我都想将数据写入该文件。我遇到的问题是，它会在第二次输入时覆盖数据。如何将数据添加到文件末尾

 public boolean save_to_csv(){

    //check if directory exists, if not create the folder
    File folder = new File(Environment.getExternalStorageDirectory() + "/HKA_CAL");
    //Environment.getExternalStorageDirectory() get the location of external storage
    boolean success = true;
    if(!folder.exists())
    {
       success = folder.mkdir();
    }         
    if (success) 
    { 
        //success is true if folder has successfully been created
        //now we can create/check if the file exists

        File stored_hka = new File(Environment.getExternalStorageDirectory()+"/HKA_CAL/Stored_values.csv");
        boolean file_existed=true;

        try{
            if(!stored_hka.exists()){
                stored_hka.createNewFile();
                file_existed=false;
            }
            FileOutputStream fOut = new FileOutputStream(stored_hka);
            OutputStreamWriter myOutWriter = new OutputStreamWriter(fOut);
            if(!file_existed){
                //if the file did not exist we need to write the titles of the csv
                myOutWriter.append("Calibration Tracking\r\n");
                myOutWriter.append(",ZERO1,,Zero2,,cal1,,cal2,,CALIBRATION FACTORS\r\n");
                myOutWriter.append("Date,Stab,Read,Stab,Read,Stab,Read,Stab,Read,Unit S/N,F Zero,F Offset,F Factor\r\n");
            }
            myOutWriter.append("Date"
                    +","+get_step3_stab()+","+get_step3_read()
                    +","+get_step6_stab()+","+get_step6_read()
                    +","+get_step8_stab()+","+get_step8_read()
                    +","+get_step11_stab()+","+get_step11_read()
                    +","+get_sn_num()+","+get_f_zero()
                    +","+get_f_offset()+","+get_f_factor()+"\r\n"
                    );
            myOutWriter.close();
            fOut.close();
        }
        catch(Exception e){
            return false;
        }




        return true;
    }
    else 
    {
        return false;
    }



}

Answer 1

使用FileOutputStream constructor，其中包含用于追加的布尔值

Answer 2

FileInputStream("valid path of file", true);

它将以追加模式打开一个文件。布尔值用于确定是否要在追加模式下打开文件

Answer 3

在构造FileWriter或FileOutputStream时，有一个构造函数参数允许您将其置于附加模式：

new FileOutputStream( "/path/to/file", true )

Answer 4

改变

FileOutputStream fOut = new FileOutputStream(stored_hka);

到

FileOutputStream fOut = new FileOutputStream(stored_hka, true);

Answer 5

而不是

new FileOutputStream(stored_hka);

做

new FileOutputStream(stored_hka, true);

这将以追加模式打开文件stored_hka，而不是覆盖内容。有关更多信息，请参阅FileOutputStream(String name, boolean append)的javadoc