How to allow entry of only month-year combinations in Java Spring Boot. I need to ensure that the user (Postman client) can enter a record (randomly generated value) for each month of the current year. For example: month: February -> year: 2020 -> generatedValue = random. When the user enters February 2020 again, it throws an exception. I've tried storing the year and month in separate lists to check if the month of that year already exists in the database, but to no avail. First in the RecordService if I want to see if there is no current year entered by the user. For example, if there is no year 2021, then the "if" should add that year to the list so that I can check the month-year combination. It works, but not what I need because the second if always throws a RuntimeException() unless I enter a year that hasn't been entered yet (e.g. there are 2020, 2021, and 2022, but not 2023), so when the user When adding:

{ "month": "March", "year": "2023", "readingTime": "1" }

The code will work because there is no year 2023 in the list, but as soon as they try to enter

{ "month": "May", "year": "2023", "readingTime": "1" }

It won't work because the year already exists, even though it should work because there is no combination for May 2023 in the database. I tried using a boolean to check if the combination exists but that doesn't make any sense to me. So please help :) Here is my code.

RecordController.java

@PostMapping("/{client_id}") public Record add(@PathVariable Long client_id, @RequestBody Record record){ return recordService.add(client_id, record); }

RecordService.java

public Record add(Long client_id, Record record){ List monthList = months(); List yearList = years(); Record recordSave = new Record(); recordSave.setId(client_id); recordSave.setYear(record.getYear()); recordSave.setMonth(record.getMonth()); recordSave.setReadingTime(record.getReadingTime()); recordSave.setReadingValue(randomGenerate()); //Does not work if (!yearList.contains(recordSave.getYear())){ yearList.add(recordSave.getYear()); } //Does not work if (monthList.contains(recordSave.getMonth()) && yearList.contains(recordSave.getYear())){ throw new RuntimeException(); } else { recordRepository.save(recordSave); } return null; }

记录.java

@Data @Entity @Table(name = "record") @JsonIgnoreProperties({"hibernateLazyInitializer","handler","device"}) public class Record implements Serializable { @Id @GeneratedValue(strategy= GenerationType.IDENTITY) private Long id; String month; Integer year; String readingTime; Float readingValue; boolean isPresent; }

RandomGenerateValue 和月年函数

public Float randomGenerate(){ int max = 105, min = 14; float random_float = (float)Math.floor(Math.random()*(max-min 1) min); return random_float; } public List months(){ List monthList = new ArrayList<>(); monthList.add("January"); monthList.add("February"); monthList.add("March"); monthList.add("April"); monthList.add("May"); monthList.add("June"); monthList.add("July"); monthList.add("August"); monthList.add("September"); monthList.add("October"); monthList.add("November"); monthList.add("December"); return monthList; } public List years(){ List yearList = new ArrayList<>(); yearList.add(2020); yearList.add(2021); return yearList; }