Project training 11 - regular backup of database

   In the last blog, I talked about how to back up a specific database , This blog will discuss how to backup some databases regularly .
   The method used for scheduled backup is the same as before , Use Runtime.getRuntime().exec(command) Execute command line statements , Backup sql The file is stored in a folder in the specified path . call DBService That is, the database service object can obtain the user database stored in the system database , Store it in List in . loop List.size() frequency , according to List Of index Back up one database at a time . The problem now is how to perform tasks regularly . The implementation method is to start a thread and then back up a database . Use cron Period of storage timing , With "0 30 9 * * ?" For example , first place 0 Express 0 second , Second 30 Express 30 minute , Third 9 Morning 9 when , The rest of the bits are replaced by other symbols to represent the... Of each day 9:30. Here is the timing code ：

@Configuration // Tag configuration class , Both Component The effect of 
@EnableScheduling // Turn on timed tasks 
public class SimpleScheduleConfig implements SchedulingConfigurer{
    

    @Autowired
    private DBService dbService;

    @SneakyThrows
    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
    
        List<DB> dbList=dbService.findDBList();
        Thread thread = new Thread(){
    
            @SneakyThrows
            @Override
            public void run() {
    
                super.run();
                int dbid;
                for(int i=0; i<dbList.size(); i++){
    
                    dbid=dbList.get(i).getId();
                    dbService.backupDB(dbid);

                }
            }
        };

        taskRegistrar.addTriggerTask(
                thread,
                triggerContext -> {
    
                    // Execution cycle every day 9 spot 30 branch 
                    String cron = "0 30 9 * * ?";
                    // Non empty verification 
                    if(StringUtils.isEmpty(cron)){
    
                        //TODO
                    }
                    // Return to execution cycle 

                    return new CronTrigger(cron).nextExecutionTime(triggerContext);
                }
        );

    }
}

Console run results ：

Display in folder ：

   Before sql The file naming format is database name + The current date +.sql, If the backup cycle is very frequent , Multiple backups in a day , It will cause the files backed up later to overwrite the previous files , Will affect the data . So I changed the naming format , Now the database name + The current date + current time +.sql. The naming code is as follows ：

        Date date = new Date();
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String dt=df.format(date);
        String datetime1=dt.replace(" ","_");
        String datetime2=datetime1.replace(":","-");
        //  Backup file name 
        String fileName = dbName+datetime2+ ".sql";

Note that the file name cannot contain spaces or colons , To replace... With other characters , Otherwise, no files will be generated .