java常见的时间处理工具类

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class GetSystemTime {

/**
* 格式化时间
* @param now
* @return
*/
public static  String  getFormatTime(Date now){
SimpleDateFormat dateFormat =  new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");//可以方便地修改日期格式
return  dateFormat.format(now).toString();
}

/**
* 获取当前时间的年
*/
public static Integer getYearByCurrentTime(){
return Integer.valueOf( Calendar.getInstance().get(Calendar.YEAR));
}

/**
* 获取当前时间的月
*/
public static Integer getMonthByCurrentTime(){
return Integer.valueOf( Calendar.getInstance().get(Calendar.MONTH)) + 1;
}

/**
* 获取当前时间的日
*/
public static Integer getDayByCurrentTime(){
return Integer.valueOf( Calendar.getInstance().get(Calendar.DAY_OF_MONTH));
}

/**
* 获取当前时间的小时
*/
public static Integer getHourByCurrentTime(){
return Integer.valueOf( Calendar.getInstance().get(Calendar.HOUR_OF_DAY));
}

/**
*获取当前时间之前或之后几年 year
*/
public static String getTimeByYear(int year) {
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.YEAR, year);
return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(calendar.getTime());
}
/**
*获取当前时间之前或之后几月 month
*/
public static String getTimeByMonth(int month) {
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.MONTH, month);
return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(calendar.getTime());
}

/**
*获取当前时间之前或之后几天 day
*/
public static String getTimeByDay(int day) {
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.DATE, day);
return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(calendar.getTime());
}

/**
*获取当前时间之前或之后几小时 hour
*/
public static String getTimeByHour(int hour) {
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, calendar.get(Calendar.HOUR_OF_DAY) + hour);
return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(calendar.getTime());

}

/**
*获取当前时间之前或之后几分钟 minute
*/
public static String getTimeByMinute(int minute) {
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.MINUTE, minute);
return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(calendar.getTime());
}

}