blocks|key|946148|text|List<String>+list+=+new+ArrayList<String>(Arrays.asList("",+"Hi",+null,+"How"));
System.out.println(list);
list.removeAll(Arrays.asList("",+null));
System.out.println(list);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|946149|输出：|unstyled|946150|[,+Hi,+null,+How]
[Hi,+How]|946151|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>List&lt;String&gt; list = new ArrayList&lt;String&gt;(Arrays.asList("", "Hi", null, "How"));
System.out.println(list);
list.removeAll(Arrays.asList("", null));
System.out.println(list);
</code></pre>

Output:

<pre><code>[, Hi, null, How]
[Hi, How]
</code></pre>

blocks|key|730132|text|这是一个很晚的答案，但您也可以使用Collections.singleton|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|730133|List<String>+list+=+new+ArrayList<String>(Arrays.asList("",+"Hi",+null,+"How"));
list.removeAll(Collections.singleton(null));
list.removeAll(Collections.singleton(""));|code-block|syntax|javascript|730134|entityMap^0|H|L|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Its a very late answer, but you can also use the <code>Collections.singleton</code>:

<pre><code>List&lt;String&gt; list = new ArrayList&lt;String&gt;(Arrays.asList("", "Hi", null, "How"));
list.removeAll(Collections.singleton(null));
list.removeAll(Collections.singleton(""));
</code></pre>

blocks|key|946223|text|现在我们有了Java8的lambda表达式，这是另一种方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|946224|arrayList.removeIf(item+->+item+==+null+%7C%7C+"".equals(item));|code-block|syntax|javascript|946225|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|$]]

Another way to do this now that we have Java 8 lambda expressions.

<pre><code>arrayList.removeIf(item -&gt; item == null || "".equals(item));
</code></pre>

blocks|key|730366|text|如果您使用的是Java8，那么可以尝试使用lambda+expression和org.apache.commons.lang.StringUtils，这也会清除array输入中的null和blank值|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|730367|public+static+String[]+cleanArray(String[]+array)+{
++++return+Arrays.stream(array).filter(x+->+!StringUtils.isBlank(x)).toArray(String[]::new);
}|code-block|syntax|javascript|730368|ref+-+https://stackoverflow.com/a/41935895/9696526|730369|entityMap|0|LINK|mutability|MUTABLE|url|https://commons.apache.org/proper/commons-lang/javadocs/api-2.6/org/apache/commons/lang/StringUtils.html#isBlank(java.lang.String))|1|https://stackoverflow.com/a/41935895/9696526^0|28|5|2H|4|2M|5|13|Z|0|0|0|6|18|1|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@$9|13|A|14|1|15]]|E|$]]|$1|F|3|G|5|H|7|16|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|17|8|@]|D|@$9|18|A|19|1|1A]]|E|$]]|$1|M|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]|U|$5|P|Q|R|E|$S|V]]]]

If you are using Java 8 then try this using lambda expression and <a href="https://commons.apache.org/proper/commons-lang/javadocs/api-2.6/org/apache/commons/lang/StringUtils.html#isBlank(java.lang.String)" rel="noreferrer">org.apache.commons.lang.StringUtils</a>, that will also clear <code>null</code> and <code>blank</code> values from <code>array</code> input

<pre><code>public static String[] cleanArray(String[] array) {
 return Arrays.stream(array).filter(x -&gt; !StringUtils.isBlank(x)).toArray(String[]::new);
}
</code></pre>

ref - <a href="https://stackoverflow.com/a/41935895/9696526">https://stackoverflow.com/a/41935895/9696526</a>

blocks|key|946291|text|把这个小金块放在这里：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|946292|Stream.of("",+"Hi",+null,+"How",+"are",+"you")
++.filter(t+->+!Strings.isNullOrEmpty(t))
++.collect(ImmutableList.toImmutableList());|code-block|syntax|javascript|946293|我真心希望Java有一个filterNot。|offset|length|style|CODE|946294|entityMap^0|0|0|C|9|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Going to drop this lil nugget in here:

<pre><code>Stream.of("", "Hi", null, "How", "are", "you")
 .filter(t -&gt; !Strings.isNullOrEmpty(t))
 .collect(ImmutableList.toImmutableList());
</code></pre>

I wish with all of my heart that Java had a <code>filterNot</code>.

blocks|key|946351|text|如果你使用上面的一个答案得到UnsupportedOperationException，而你的List是从Arrays.asList()创建的，那是因为你不能编辑这样的List。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|946352|要修复此问题，请将Arrays.asList()包装在new+LinkedList<String>()中|946353|++++List<String>+list+=+new+LinkedList<String>(Arrays.asList(split));|code-block|syntax|javascript|946354|来源来自此answer。|946355|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/2965808^0|E|T|1B|4|1H|F|2C|4|0|9|F|R|O|0|0|5|6|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]|$9|13|A|14|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|15|8|@$9|16|A|17|B|C]|$9|18|A|19|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|1A|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1B|8|@]|D|@$9|1C|A|1D|1|1E]]|E|$]]|$1|O|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

If you get <code>UnsupportedOperationException</code> from using one of ther answer above and your <code>List</code> is created from <code>Arrays.asList()</code>, it is because you can't edit such <code>List</code>.

To fix, wrap the <code>Arrays.asList()</code> inside <code>new LinkedList&lt;String&gt;()</code>:

<pre><code> List&lt;String&gt; list = new LinkedList&lt;String&gt;(Arrays.asList(split));
</code></pre>

Source is from this <a href="https://stackoverflow.com/a/2965808">answer</a>.

blocks|key|946233|text|+++private+List+cleanInputs(String[]+inputArray)+{
++++++++List<String>+result+=+new+ArrayList<String>(inputArray.length);
++++++++for+(String+input+:+inputArray)+{
++++++++++++if+(input+!=+null)+{
++++++++++++++++String+str+=+input.trim();
++++++++++++++++if+(!str.isEmpty())+{
++++++++++++++++++++result.add(str);
++++++++++++++++}
++++++++++++}
++++++++}
++++++++return+result;
++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|946234|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> private List cleanInputs(String[] inputArray) {
 List&lt;String&gt; result = new ArrayList&lt;String&gt;(inputArray.length);
 for (String input : inputArray) {
 if (input != null) {
 String str = input.trim();
 if (!str.isEmpty()) {
 result.add(str);
 }
 }
 }
 return result;
 }
</code></pre>

blocks|key|730371|text|List<String>+list+=+new+ArrayList<String>(Arrays.asList("",+"Hi",+"",+"How"));
+++++++++++Stream<String>+stream+=+list+.stream();
+++++++++++Predicate<String>+empty+=+empt->(empt.equals(""));
++++++++++++Predicate<String>+emptyRev+=+empty.negate();
+++++++++++list=++stream.filter(emptyRev).collect(Collectors.toList());|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|730372|或|unstyled|730373|list+=++list+.stream().filter(empty->(!empty.equals(""))).collect(Collectors.toList());|730374|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>List&lt;String&gt; list = new ArrayList&lt;String&gt;(Arrays.asList(&quot;&quot;, &quot;Hi&quot;, &quot;&quot;, &quot;How&quot;));
 Stream&lt;String&gt; stream = list .stream();
 Predicate&lt;String&gt; empty = empt-&gt;(empt.equals(&quot;&quot;));
 Predicate&lt;String&gt; emptyRev = empty.negate();
 list= stream.filter(emptyRev).collect(Collectors.toList());
</code></pre>
OR
<pre><code>list = list .stream().filter(empty-&gt;(!empty.equals(&quot;&quot;))).collect(Collectors.toList());
</code></pre>

blocks|key|730413|text|lukastymo的答案似乎是最好的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|730414|但由于这种方法的可扩展性，它可能也值得一提：|730415|List<String>+list+=+new+ArrayList<String>(Arrays.asList("",+"Hi",+null,+"How",+"are"));

list+=+list.stream()
+++++++++++.filter(item+->+item+!=+null+&&+!item.isEmpty())
+++++++++++.collect(Collectors.toList());

System.out.println(list);|code-block|syntax|javascript|730416|我的意思是，您可以添加其他过滤器，例如：|730417|++++++++++.filter(item+->+!item.startsWith("a"))|730418|..。当然，这和这个问题没有什么特别的关系。|730419|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

lukastymo's answer seems the best one.
But it may be worth mentioning this approach as well for it's extensibility:
<pre><code>List&lt;String&gt; list = new ArrayList&lt;String&gt;(Arrays.asList(&quot;&quot;, &quot;Hi&quot;, null, &quot;How&quot;, &quot;are&quot;));

list = list.stream()
 .filter(item -&gt; item != null &amp;&amp; !item.isEmpty())
 .collect(Collectors.toList());

System.out.println(list);
</code></pre>
What I mean by that is you could then add additional filters, such as:
<pre><code> .filter(item -&gt; !item.startsWith(&quot;a&quot;))
</code></pre>
... although of course that's not specifically relevant to the question.

In Java, I have an ArrayList of Strings like:

<pre><code>[,Hi, ,How,are,you]
</code></pre>

I want to remove the null and empty elements, how to change it so it is like this:

<pre><code>[Hi,How,are,you]
</code></pre>

In Java, remove empty elements from a list of Strings

Java

在Java语言中，我有一个字符串的ArrayList，如下所示：[,Hi, ,How,are,you]我想要删除null和空元素，如何将其更改为如下所示：[Hi,How,are,you]

问在Java中，从字符串列表中删除空元素
EN

回答 9

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