String轉LocalDateTime,LocalDateTime轉String，Date轉String，String轉Date

package com.wanmi.sbc.common.util;

import org.apache.commons.lang3.StringUtils;

import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
import java.util.Calendar;
import java.util.Date;

/**
 * Created by zhangjin on 2017/4/28.
 */
public class DateUtil {

    public static final String FMT_DATE_1 = "yyyy-MM-dd";

    public static final String FMT_TIME_1 = "yyyy-MM-dd HH:mm:ss";

    public static final String FMT_TIME_2 = "yyyy-MM-dd HH:mm";

    public static final String FMT_TIME_3 = "yyyyMMddHHmmss";

    public static final String FMT_DATE_3 = "MMddHH";

    public static final String FMT_TIME_4 = "yyyy-MM-dd HH:mm:ss.SSS";

    public static final String FMT_TIME_5 = "yyyyMMdd";

    public static final String FMT_TIME_6 = "yyyy-MM-dd HH";

    /**
     * 轉換類型 string to LocalDateTime
     *
     * @param time time
     * @return LocalDateTime
     */
    public static LocalDateTime parseDate(String time) {
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern(FMT_TIME_2);
        return LocalDateTime.of(LocalDate.parse(time, formatter), LocalTime.MIN);
    }

    /**
     * 轉換類型 string to LocalDateTime
     *
     * @param time time
     * @return LocalDateTime
     */
    public static String getDate(LocalDateTime time) {
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern(FMT_DATE_1);
        return formatter.format(time);
    }

    /**
     * 轉換類型 string to LocalDateTime
     * 2017-06-23 -> 2017-06-23 00:00
     *
     * @param time time
     * @return LocalDateTime
     */
    public static LocalDateTime parseDay(String time) {
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern(FMT_DATE_1);
        return LocalDate.parse(time, formatter).atStartOfDay();
    }


    /**
     * 獲取全部當前時間
     * @return
     */
    public static String nowTime(){
        return format(LocalDateTime.now(), FMT_TIME_1);
    }

    /**
     * 獲取當前時間
     * @return
     */
    public static String nowDate(){
        return format(LocalDateTime.now(),FMT_DATE_1);
    }

    /**
     * 獲取當前時間 到小時
     * @return
     */
    public static String nowHourTime(){
        return format(LocalDateTime.now(),FMT_TIME_6);
    }

    /**
     * 獲取當前時間10位時間戳
     * @return
     */
    public static String nowTen() {
        int now = (int) (System.currentTimeMillis() / 1000);
        return String.valueOf(now);
    }

    /**
     * 獲取昨天時間
     * @return
     */
    public static String yesterdayDate(){
        Calendar cal=Calendar.getInstance();
        cal.add(Calendar.DATE,-1);

        return format(cal.getTime(),FMT_DATE_1);
    }

    /**
     * 獲取明天時間
     * @return
     */
    public static String tomorrowDate(){
        Calendar cal=Calendar.getInstance();
        cal.add(Calendar.DATE,1);

        return format(cal.getTime(),FMT_DATE_1);
    }


    /**
     * 轉換類型  LocalDateTime to string
     *
     * @param time time
     * @return LocalDateTime
     */
    public static String format(LocalDateTime time, String fmt) {
        return time.format(DateTimeFormatter.ofPattern(fmt));
    }

    /**
     * 轉換類型  Date to string
     *
     * @param time time
     * @return LocalDateTime
     */
    public static String format(Date time, String fmt) {
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat(fmt);
        return simpleDateFormat.format(time);
    }

    /**
     * 轉換類型  string to LocalDateTime
     *
     * @param time time
     * @return LocalDateTime
     */
    public static LocalDateTime parse(String time, String fmt) {
        return LocalDateTime.parse(time, DateTimeFormatter.ofPattern(fmt));
    }

    /**
     * 時間類型轉換爲LocalDateTime, 針對*request中帶有canEmpty註解的時間屬性
     * 如果沒有canEmpty註解, 需要在外層判斷爲空則不調用該方法
     * 使用時需要位於copyProperties上方
     * 場景: 修改信息,
     *   有值:
     *     1.前端如果修改值, 傳遞到後端則爲yyyy-MM-dd類型, 長度爲10
     *     2.如果不做修改則爲yyyy-MM-dd HH:mm:ss.SSS類型
     *   無值:
     *     保存爲null
     * @param time 時間
     * @return
     */
    public static LocalDateTime parseDayCanEmpty(String time) {
        DateTimeFormatter formatter1 = DateTimeFormatter.ofPattern(FMT_DATE_1);
        DateTimeFormatter formatter2 = DateTimeFormatter.ofPattern(FMT_TIME_4);
        if(StringUtils.isNotBlank(time)) {
            if(time.length() == 10) {
                return LocalDateTime.of(LocalDate.parse(time, formatter1), LocalTime.MIN);
            } else {
                return LocalDateTime.parse(time, formatter2);
            }
        }
        return null;
    }
}