java 已知一个Date(),获取前一天和后一天

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

public class DateUtil {

public static void main(String[] args) {
Date date = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String specifiedDay = sdf.format(date);
System.out.println(getSpecifiedDayBefore(specifiedDay));
System.out.println(getSpecifiedDayAfter(specifiedDay));
}

/**
* 获得指定日期的前一天
*
* @param specifiedDay
* @return
* @throws Exception
*/
public static String getSpecifiedDayBefore(String specifiedDay) {//可以用new Date().toLocalString()传递参数
Calendar c = Calendar.getInstance();
Date date = null;
try {
date = new SimpleDateFormat("yy-MM-dd").parse(specifiedDay);
} catch (ParseException e) {
e.printStackTrace();
}
c.setTime(date);
int day = c.get(Calendar.DATE);
c.set(Calendar.DATE, day - 1);

String dayBefore = new SimpleDateFormat("yyyy-MM-dd").format(c
.getTime());
return dayBefore;
}

/**
* 获得指定日期的后一天
*
* @param specifiedDay
* @return
*/
public static String getSpecifiedDayAfter(String specifiedDay) {
Calendar c = Calendar.getInstance();
Date date = null;
try {
date = new SimpleDateFormat("yy-MM-dd").parse(specifiedDay);
} catch (ParseException e) {
e.printStackTrace();
}
c.setTime(date);
int day = c.get(Calendar.DATE);
c.set(Calendar.DATE, day + 1);

String dayAfter = new SimpleDateFormat("yyyy-MM-dd")
.format(c.getTime());
return dayAfter;
}
}