java计算几个日期中距离现在最近的日期
public static void main(String[] args) throws Exception {
String a="2019-07-26";
String b="2019-07-27";
String c="2019-07-31";
String d="2019-07-24";
String e="2019-07-01";
String f="2019-08-01";
String[] arr = new String[]{b,a,c,d,e, f};
System.out.println(getNearestDate(arr));
}
private static String getNearestDate(String[] arr){
SimpleDateFormat smf = new SimpleDateFormat("yyyy-MM-dd");
long[] brr =new long[arr.length];
Map<Long,String> map = new HashMap<Long,String>();
int idx=0;
for(String str : arr){
Date da = null;
try {
da = smf.parse(str);
} catch (ParseException e) {
e.printStackTrace();
}
Calendar ca = Calendar.getInstance();
ca.setTime(da);
long dtLong = ca.getTimeInMillis();
brr[idx]=dtLong;
idx++;
System.out.println(str+"--"+dtLong);
map.put(dtLong, str);
}
Calendar ca = Calendar.getInstance();
try {
ca.setTime(smf.parse( smf.format(ca.getTime() )));
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
long dtLong = ca.getTimeInMillis();
System.out.println("now-"+dtLong);
long des=0;
idx=0;
// 最近日期
String minDate = null;
for(Long lon : brr){
long ndes = Math.abs(dtLong - lon);
if(idx==0){
des = ndes;
minDate=map.get(lon);
}
if(ndes<des){
des = ndes;
minDate=map.get(lon);
}
idx++;
}
return minDate;
}取最近的日期且大于等于今天
private static String getNearestGtDate(String[] arr){
SimpleDateFormat smf = new SimpleDateFormat("yyyy-MM-dd");
long[] brr =new long[arr.length];
Map<Long,String> map = new HashMap<Long,String>();
int idx=0;
for(String str : arr){
Date da = null;
try {
da = smf.parse(str);
} catch (ParseException e) {
e.printStackTrace();
}
Calendar ca = Calendar.getInstance();
ca.setTime(da);
long dtLong = ca.getTimeInMillis();
brr[idx]=dtLong;
idx++;
map.put(dtLong, str);
}
Calendar ca = Calendar.getInstance();
try {
ca.setTime(smf.parse( smf.format(ca.getTime() )));
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
long dtLong = ca.getTimeInMillis();
long des=0;
idx=0;
// 最近日期
String minDate = null;
for(Long lon : brr){
if(lon>=dtLong){
long ndes = lon-dtLong ;
if(idx==0){
des = ndes;
minDate=map.get(lon);
}
if(ndes<des){
System.out.println(des);
des = ndes;
minDate=map.get(lon);
}
idx++;
}
}
return minDate;
}