blocks|key|395165|text|默认情况下，ArrayList不支持排序。您可以使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|395166|来自java.util.Collections类的public+static+<T>+void+sort(List<T>+list,+Comparator<?+super+T>+c)。传递比较器的实现来对日期进行排序，如下所示|offset|length|style|CODE|395167|http://www.coderanch.com/t/392338/java/java/compare-Dates-String-Format|395168|entityMap|0|LINK|mutability|MUTABLE|url^0|0|2|L|P|1U|0|0|1Z|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@$D|S|E|T|F|G]|$D|U|E|V|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|W|8|@]|9|@$D|X|E|Y|1|Z]]|A|$]]|$1|J|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|I]]]]

ArrayList doesnt support sorting by default. You can use 

<code>public static &lt;T&gt; void sort(List&lt;T&gt; list, Comparator&lt;? super T&gt; c)</code> from <code>java.util.Collections</code> class. pass your implementation of comparator to sort dates, something like 

<a href="http://www.coderanch.com/t/392338/java/java/compare-Dates-String-Format" rel="nofollow">http://www.coderanch.com/t/392338/java/java/compare-Dates-String-Format</a>

blocks|key|177335|text|尝尝这个|type|unstyled|depth|inlineStyleRanges|entityRanges|data|177336|++++Collections.sort(datestring,+new+Comparator<String>()+{
++++++++DateFormat+f+=+new+SimpleDateFormat("MM/dd/yyyy+'@'hh:mm+a");
++++++++@Override
++++++++public+int+compare(String+o1,+String+o2)+{
++++++++++++try+{
++++++++++++++++return+f.parse(o1).compareTo(f.parse(o2));
++++++++++++}+catch+(ParseException+e)+{
++++++++++++++++throw+new+IllegalArgumentException(e);
++++++++++++}
++++++++}
++++});|code-block|syntax|javascript|177337|或者使用Java+8|177338|++++DateTimeFormatter+formatter+=+DateTimeFormatter.ofPattern("MM/dd/yyyy+'@'hh:mm+a");
++++Collections.sort(datestring,+(s1,+s2)+->+LocalDateTime.parse(s1,+formatter).
++++++++++++compareTo(LocalDateTime.parse(s2,+formatter)));|177339|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

try this

<pre><code> Collections.sort(datestring, new Comparator&lt;String&gt;() {
 DateFormat f = new SimpleDateFormat("MM/dd/yyyy '@'hh:mm a");
 @Override
 public int compare(String o1, String o2) {
 try {
 return f.parse(o1).compareTo(f.parse(o2));
 } catch (ParseException e) {
 throw new IllegalArgumentException(e);
 }
 }
 });
</code></pre>

or with Java 8 

<pre><code> DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MM/dd/yyyy '@'hh:mm a");
 Collections.sort(datestring, (s1, s2) -&gt; LocalDateTime.parse(s1, formatter).
 compareTo(LocalDateTime.parse(s2, formatter)));
</code></pre>

blocks|key|395205|text|也许你可以编写一个自定义的比较器来比较日期字符串和基于需求的顺序。然后，您将能够使用已实现的比较器对集合进行排序。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|395206|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Probably you can write a custom comparator to compare the Date Strings and order based on the requirement. Then you would be able to sort the collection with the implemented comparator.

blocks|key|177391|text|一种选择是将日期添加到TreeMap中，使用未格式化的日期作为关键字，格式化的日期作为值。使用TreeMap将自动对值进行排序。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|177392|private+ArrayList<String>+sortDates(ArrayList<String>+dates)+throws+ParseException+{
++++SimpleDateFormat+f+=+new+SimpleDateFormat("dd+MMM+yyyy");
++++Map+<Date,+String>+dateFormatMap+=+new+TreeMap<>();
++++for+(String+date:+dates)
++++++++dateFormatMap.put(f.parse(date),+date);
++++return+new+ArrayList<>(dateFormatMap.values());
}|code-block|syntax|javascript|177393|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

One option is to add the dates to a TreeMap, with the unformatted date as the key, and the formatted date as the value. Using a TreeMap will sort the values automatically.

<pre><code>private ArrayList&lt;String&gt; sortDates(ArrayList&lt;String&gt; dates) throws ParseException {
 SimpleDateFormat f = new SimpleDateFormat("dd MMM yyyy");
 Map &lt;Date, String&gt; dateFormatMap = new TreeMap&lt;&gt;();
 for (String date: dates)
 dateFormatMap.put(f.parse(date), date);
 return new ArrayList&lt;&gt;(dateFormatMap.values());
}
</code></pre>

blocks|key|177418|text|可以使用下面给出的compareTo比较字符串格式的日期列表。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|177419|ArrayList<String>+datestring=new+ArrayList<String>();
datestring.add("01/21/2013+@03:13+PM");
datestring.add("01/21/2013+@04:37+PM");
datestring.add("01/21/2013+@10:41+AM");
datestring.add("01/21/2013+@10:48+AM");
datestring.add("01/22/2013+@06:16+AM");
datestring.add("01/22/2013+@06:19+AM");
datestring.add("01/21/2013+@05:19+PM");
datestring.add("01/21/2013+@05:19+PM");

Collections.sort(datestring,+new+Comparator<String>()+{
++++++++++++++++@Override
++++++++++++++++public+int+compare(String+object1,+String+object2)+{
++++++++++++++++++++return+object1.compareTo(object2);
++++++++++++++++}
++++++++++++});|code-block|syntax|javascript|177420|通过使用它，您甚至不必将字符串解析为日期|177421|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

One can compare the List of date in string format by using the compareTo as given below.

<pre><code>ArrayList&lt;String&gt; datestring=new ArrayList&lt;String&gt;();
datestring.add("01/21/2013 @03:13 PM");
datestring.add("01/21/2013 @04:37 PM");
datestring.add("01/21/2013 @10:41 AM");
datestring.add("01/21/2013 @10:48 AM");
datestring.add("01/22/2013 @06:16 AM");
datestring.add("01/22/2013 @06:19 AM");
datestring.add("01/21/2013 @05:19 PM");
datestring.add("01/21/2013 @05:19 PM");

Collections.sort(datestring, new Comparator&lt;String&gt;() {
 @Override
 public int compare(String object1, String object2) {
 return object1.compareTo(object2);
 }
 });
</code></pre>

By using this you even dont have to parse the String into date

I have an <code>arraylist</code> with string values like

<pre><code>ArrayList&lt;String&gt; datestring=new ArrayList&lt;String&gt;();
datestring.add("01/21/2013 @03:13 PM");
datestring.add("01/21/2013 @04:37 PM");
datestring.add("01/21/2013 @10:41 AM");
datestring.add("01/21/2013 @10:48 AM");
datestring.add("01/22/2013 @06:16 AM");
datestring.add("01/22/2013 @06:19 AM");
datestring.add("01/21/2013 @05:19 PM");
datestring.add("01/21/2013 @05:19 PM");
</code></pre>

Can any body help me on sorting the above list? So that the values are sorted according to AM and PM format. 
The expected output after sorting should be

<pre><code>for (String s : datestring)
{
 System.out.println(s);
}
</code></pre>

.

<pre><code>01/21/2013 @10:41 AM;
01/21/2013 @10:48 AM;
01/21/2013 @03:13 PM;
01/21/2013 @04:37 PM;
01/21/2013 @05:16 PM;
01/21/2013 @05:19 PM;
01/22/2013 @06:16 AM;
01/22/2013 @06:19 AM;
</code></pre>

How to sort Date which is in string format in java?

Java

我有一个包含字符串值的arraylist，比如ArrayList<String> datestring=new ArrayList<String>();datestring.add("01/21/2013 @03:13 PM");datestring.add("01/21/2013 @04:37 PM");datest...

问如何在java中对字符串格式的日期进行排序？
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