java - Filewriter 创建一个只读文件

Question

我使用文件编写器以类似 CSV 的格式将对象数组列表作为字符串写入文件。不管怎样，我在让它工作时遇到了问题，但现在我收到一个 FileNotFound 异常，它说创建的文件在异常中是只读的。正如我检查的那样，该文件已创建，但显然无法写入。然而，我实际上想覆盖内容，但出现此错误。

        ///Like a CSV file. 
        try{
            FileWriter writer_file = new FileWriter("PeopleDetailsFile");

            String filestring = ""; ///initializes filestring, which is written to the file.
            for(PeopleDetails person : peopledetails_file){
                String person_detail_string = "";
                person_detail_string = person.name + "," + person.number;
                filestring = filestring + person_detail_string + ";";

            }
            writer_file.write(filestring);
            writer_file.close();
        }
            catch (IOException e) {
                Log.e("ERROR", e.toString());

        }finally{
            ///Hopefully won't get an error here.
            Intent switch_menu = new Intent(this, MenuList.class);
            startActivity(switch_menu);
        }

Answer 1

尝试使用PrintWriter。我在下面为您提供一些简短的指导方针，但需要进行修改。此外，请注意，我将姓名和号码保存在不同的行中，因此当您阅读详细信息时，您应该使用相同的方法。

 public void writeToFile(String fileName, ArrayList<PeopleDetails> peopledetails) {
        try {
            /*
             * Create a FileWriter object that handles the low-level details of
             * writing
             */
            FileWriter theFile = new FileWriter(fileName);

            /* Create a PrintWriter object to wrap around the FileWriter object */
            /* This allows the use of high-level methods like println */
            PrintWriter fileOut = new PrintWriter(theFile);

            /* Print some lines to the file using the println method */
            for (int i = 0; i < peopledetails.size(); i++) {
                fileOut.println(peopledetails.get(i).getName());
                fileOut.println(peopledetails.get(i).getNumber());
            }
            /* Close the file so that it is no longer accessible to the program */
            fileOut.close();
        }

        /* Handle the exception thrown by the FileWriter methods */
        catch (IOException e) {
            System.out.println("Problem writing to the file");
        }
    } /* End of method writeToFile */