/**
 * 字符串转换成日期
 *
 * @作者：张帅
 * @日期：2019-04-22
 * @param str
 * @return date
 */
public static Date strToDate(String str) {

    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
    //ZCLG20170630 添加日期格式 mod LiGe 20170630
    if(str.indexOf(‘年‘) > -1 && str.indexOf(‘月‘) > -1 && str.indexOf(‘日‘) > -1){
        format = new SimpleDateFormat("yyyy年MM月dd日");
    }else if(str.indexOf(‘年‘) > -1 && str.indexOf(‘月‘) > -1 && str.indexOf(‘号‘) > -1){
        format = new SimpleDateFormat("yyyy年MM月dd号");
    }
    Date date = null;
    try {
        date = format.parse(str);
    } catch (ParseException e) {
        e.printStackTrace();
    }
    return date;
}

//给存储过程的参数设置值
java.util.Date d = new java.util.Date();
Calendar calendar = new GregorianCalendar();
calendar.setTime(d);
calendar.add(calendar.DATE,-1);//把日期往后增加一天.整数往后推,负数往前移动
d = calendar.getTime();//这个时间就是日期往后推一天的结果
java.sql.Date date = new java.sql.Date(d.getTime());//会丢失时分秒
Calendar calendar = new GregorianCalendar();
int currentMonth = calendar.get(Calendar.MONTH )+1;
calendar.set(calendar.get(Calendar.YEAR), currentMonth, 1);
calendar.add(calendar.DATE,-1);//把日期往后增加一天.整数往后推,负数往前移动
int day=calendar.get(Calendar.DAY_OF_MONTH);
int year = calendar.get(Calendar.YEAR);
java.sql.Date date = null;
try {
    date = (Date)new SimpleDateFormat("yyyy-MM-dd").parse(String.valueOf(year)+"-"+String.valueOf(currentMonth)+"-"+String.valueOf(day));
    //date=(Date)TimeUtils.getDate("yyyy-MM-dd",String.valueOf(year+"-"+currentMonth+"-"+day));
} catch (ParseException e) {
    e.printStackTrace();
    ConnectionUtil.rollBackTransaction(conn);
}

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date date=new Date();
String dateFormat1=sdf.format(date);
System.out.println(dateFormat1);
System.out.println(date);
Calendar calendar=Calendar.getInstance();
calendar.setTime(date);
calendar.add(Calendar.DATE, 4);
Date date2=calendar.getTime();
System.out.println(date2); 
String dateFormat=sdf.format(date2);
System.out.println(dateFormat);

String year1=String.format("%tY", startDate);
String year2=String.format("%tY", endDate);
String mon1=String .format("%tm", startDate);
String mon2=String .format("%tm", endDate);
String day1=String .format("%td", startDate);
String day2=String .format("%td", endDate);

ChronoUnit
Duration

//得到执行时间
/*String times="2018-03-31";
Date date=null;
try {
    date= TimeUtils.getDate(times,"yyyy-MM-dd");
} catch (ParseException e) {
    e.printStackTrace();
}
long t0 = System.currentTimeMillis(); // 代码执行前时间
BigDecimal exch=null;
for(int i=0;i<=400;i++){
    exch=dataDictionaryService.getExch("CNY","CNY",date);
}

long t1 = System.currentTimeMillis(); // 代码执行后时间
Calendar c = Calendar.getInstance();
c.setTimeInMillis(t1 - t0);
System.out.println("耗时: " + c.get(Calendar.MINUTE) + "分 "
        + c.get(Calendar.SECOND) + "秒 " + c.get(Calendar.MILLISECOND)
        + " 微秒");

package com.asd.common.utils.datetag;
import java.util.Date;
public class DateTag {
   private Date startDate;
   private Date lastDate;
   private StringBuilder info =  new StringBuilder();
   private int messageIndex = 0;

   public DateTag(String message) {
      this.lastDate = new Date();
      this.startDate = new Date();
      info.append(message);
      info.append("：");
      this.messageIndex = message.length()+1;
   }
   public void appendDate(String message){
      info.append(message);
      info.append("：");
      info.append(new Date().getTime()-lastDate.getTime());
      info.append("；");
      this.lastDate = new Date();
   }
   public void addFist(String message){
      info.insert(messageIndex, "；");
      info.insert(messageIndex, new Date().getTime()-startDate.getTime());
      info.insert(messageIndex, "：");
      info.insert(messageIndex, message);
      this.lastDate = new Date();
   }
   public String getInfo(){
      return info.toString();
   }
}
DateTag tag = new DateTag("sss");
BigDecimal ss = exch == null ? BigDecimal.ZERO : exch.getExchRate().divide(new BigDecimal(exch.getBase()));
tag.appendDate("从数据字段获取用时");
tag.addFist("总用时");
System.out.println(tag.getInfo());