Java时间格式Date/LocalDateTime/LocalDate/String/long(时间戳)互转

本是古典何须时尚 2023-01-18 14:25 24阅读 0赞

### 目录 ###

*  转Date
 *   *   *  LocalDateTime转Date
         *  LocalDate转Date
         *  String转Date
         *  long(时间戳)转Date
 *  转LocalDateTime
 *   *   *  Date转LocalDateTime
         *  LocalDate转LocalDateTime
         *  String转LocalDateTime
         *  long(时间戳)转LocalDateTime
 *  转LocalDate
 *   *   *  Date转LocalDate
         *  LocalDateTime转LocalDate
         *  String转LocalDate
         *  long(时间戳)转LocalDate
 *  转String
 *   *   *  Date转String
         *  LocalDateTime转String
         *  LocalDate转String
         *  long(时间戳)转String
 *  转long(时间戳)
 *   *   *  Date转long(时间戳)
         *  LocalDateTime转long(时间戳)
         *  LocalDate转long(时间戳)
         *  String转long(时间戳)

# 转Date #

### LocalDateTime转Date ###

ZoneId zone = ZoneId.systemDefault();
    
    LocalDateTime dateTime = LocalDateTime.now();
    ZonedDateTime zdf = dateTime.atZone(zone);
    Date date = Date.from(zdf.toInstant());

### LocalDate转Date ###

ZoneId zone = ZoneId.systemDefault();
    
    LocalDate localDate = LocalDate.now();
    // 实质上是把LocalDate先转成了LocalDateTime
    ZonedDateTime zdf = localDate.atStartOfDay().atZone(zone);
    Date date = Date.from(zdf.toInstant());

### String转Date ###

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    try { 
        Date date = sdf.parse("2021-01-01 00:00:00");
    } catch (ParseException e) { 
        e.printStackTrace();
    }

### long(时间戳)转Date ###

long timestamp = System.currentTimeMillis();
    Date date = new Date(timestamp);

# 转LocalDateTime #

### Date转LocalDateTime ###

ZoneId zone = ZoneId.systemDefault();
    
    Date date = new Date();
    LocalDateTime dateTime = date.toInstant().atZone(zone).toLocalDateTime();

### LocalDate转LocalDateTime ###

LocalDate localDate = LocalDate.now();
    LocalDateTime dateTime = localDate.atStartOfDay();

### String转LocalDateTime ###

DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
    LocalDateTime dateTime = LocalDateTime.parse("2021-01-01 00:00:00", df)

### long(时间戳)转LocalDateTime ###

ZoneId zone = ZoneId.systemDefault();
    
    long timestamp = System.currentTimeMillis();
    LocalDateTime dateTime = LocalDateTime.ofInstant(Instant.ofEpochMilli(timestamp), zone);

# 转LocalDate #

### Date转LocalDate ###

ZoneId zone = ZoneId.systemDefault();
    
    Date date = new Date();
    LocalDate localDate = date.toInstant().atZone(zone).toLocalDate();

### LocalDateTime转LocalDate ###

LocalDateTime dateTime = LocalDateTime.now();
    LocalDate localDate = dateTime.toLocalDate();

### String转LocalDate ###

DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    LocalDate localDate = LocalDate.parse("2021-01-01", df)

### long(时间戳)转LocalDate ###

ZoneId zone = ZoneId.systemDefault();
    
    long timestamp = System.currentTimeMillis();
    LocalDate localDate = Instant.ofEpochMilli(timestamp).atZone(zone).toLocalDate();

# 转String #

### Date转String ###

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    Date date = new Date();
    String s = sdf.format(date);

### LocalDateTime转String ###

DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
    LocalDateTime dateTime = LocalDateTime.now();
    String s = df.format(dateTime);

### LocalDate转String ###

DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    LocalDate localDate = LocalDate.now();
    String s1 = df.format(localDate);
    // or
    String s2 = localDate.toString();

### long(时间戳)转String ###

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    long timestamp = System.currentTimeMillis();
    Date date = new Date(timestamp);
    String s = sdf.format(date);

# 转long(时间戳) #

### Date转long(时间戳) ###

Date date = new Date();
    long timestamp = date.getTime();

### LocalDateTime转long(时间戳) ###

LocalDateTime dateTime = LocalDateTime.now();
    long timestamp = Timestamp.valueOf(dateTime).getTime();

### LocalDate转long(时间戳) ###

LocalDate localDate = LocalDate.now();
    long timestamp = Timestamp.valueOf(localDate.atStartOfDay()).getTime();

### String转long(时间戳) ###

String s = "2021-01-01 00:00:00";
    long timestamp = Timestamp.valueOf(s).getTime();