Java8---LocalDate和LocalDateTime用于时间比较

判断当前时间或者当前时刻是否在某个时间范围内

例如：

public static final DateTimeFormatter YYYYMMDD_PATTERN_FORMARTTER = DateTimeFormatter .ofPattern("yyyyMMdd");

public static final DateTimeFormatter YYYY_MM_DD_PATTERN_FORMARTTER = DateTimeFormatter .ofPattern("yyyy_MM_dd");

public static final DateTimeFormatter YYYYMMDDHHMMSS_PATTERN_FORMARTTER = DateTimeFormatter .ofPattern("yyyyMMddHHmmss");

public static final DateTimeFormatter YYYY_MM_DD_HH_MM_SS_PATTERN_FORMARTTER = DateTimeFormatter .ofPattern("yyyy_MM_dd HH:mm:ss");

String start = "20211101"；
String end = "20211108";
LocalDate  startDate = LocalDate.parse(getDateString(start),YYYY_MM_DD_PATTERN_FORMARTTER );
LocalDate  endDate = LocalDate.parse(getDateString(end ),YYYY_MM_DD_PATTERN_FORMARTTER );
LocalDate nowDate = LocalDate.now();
String begin = "";
if(endDate .isBefore(nowDate ) || startDate .isAfter(nowDate )){
    begin = "false";
}else{
    begin = "on";
}

String startTime = "20211101100000"；
String endTime = "20211108100000";
LocalDateTime  startDateTime = LocalDateTime.parse(getDateTimeString(startTime ),YYYY_MM_DD_HH_MM_SS_PATTERN_FORMARTTER );
LocalDateTime  endDateTime = LocalDateTime.parse(getDateTimeString(endTime  ),YYYY_MM_DD_HH_MM_SS_PATTERN_FORMARTTER );
LocalDateTime  nowDateTime = LocalDateTime.now();
String begin1 = "";
if(endDateTime .isBefore(nowDateTime) || startDateTime  .isAfter(nowDateTime )){
    begin1 = "false";
}else{
    begin1 = "on";
}

//将“yyyyMMdd”格式字符串转换成“yyyy_MM_dd”格式字符串
private String getDateString(String str){
	  LocalDate parse = **LocalDate**.parse(str, YYYYMMDD_PATTERN_FORMARTTER );
	  String format = parse.format (YYYY_MM_DD_PATTERN_FORMARTTER);
	  return format ;
}

//将“yyyyMMddHHmmss”格式字符串转换成“yyyy_MM_dd HH:mm:ss”格式字符串
private String getDateTimeString(String str){
	  LocalDate parse = **LocalDateTime**.parse(str, YYYYMMDDHHMMSS_PATTERN_FORMARTTER );
	  String format = parse.format(YYYY_MM_DD_HH_MM_SS_PATTERN_FORMARTTER );
	  return format ;
}