Delete the content of csv file in Java

Question

Every day I update a csv file using a FileWriter. When we step into a new month I have to delete the data from the previous month. My below code only updates a data in a csv file so, please help in deleting the previous month's data.

At least I need to know how to delete the data in csv file using FileWriter, so that I can manage to code for deleting previous month data.

        private static void eventsUpdate(HttpServletRequest request,
                                         HttpServletResponse response)  {
            String date=request.getParameter("date");   //getting from jsp page 
            String event=request.getParameter("event"); //getting from jsp page


            File file = new File( "D:///events/events.csv");  
            if ( !file.exists() )
                file.createNewFile();

            FileWriter fw = new FileWriter(file,true);
            BufferedWriter writer = new BufferedWriter( fw );
            writer.write(date);
            writer.write(",");
            writer.write(event);

            System.out.println("writing into excel");
            writer.newLine();
            writer.close();
            fw.close();

        }

Answer 1

Actually when you use the true argument in your FileWriter instantiation, you create a file writer object in append mode.

FileWriter fw = new FileWriter(file,false);

如果您不使用该true选项，则文件将被新内容覆盖。因此，我建议遵循以下路线图：

1. 整体读取文件内容 String
2. 从特定内容中删除您要删除的内容 String
3. 使用特定内容中的新内容覆盖文件内容 String

希望我能帮上忙！