Java Commons Collections removeAll

本文介绍了Java Commons Collections removeAll的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 CollectionUtils :: removeAll（）Commons Collections 3.2.1 我必须疯了，因为看起来这个方法是做什么的文档状态：这个小JUnit测试 @Test public void testCommonsRemoveAll（）throws Exception { String str1 =foo; String str2 =bar; String str3 =qux; List< String> collection = Arrays.asList（str1，str2，str3）; System.out.println（collection：+ collection）; List< String> remove = Arrays.asList（str1）; System.out.println（remove：+ remove）; 集合result = CollectionUtils.removeAll（collection，remove）; System.out.println（result：+ result）; assertEquals（2，result.size（））; } 失败 java.lang.AssertionError：expected：< 2>但是：< 1> 并打印 集合：[foo，bar，qux] remove：[foo] result ：[foo] 从我阅读的文档，我应该期望 [bar ，qux] 。 解决方案 编辑2014年1月1日 Apache Commons Collections 4.0终于发布2013年11月21日，并包含此问题的修正。 链接到 CollectionUtils.java 有问题的行（1688 - 1691），并确认该方法之前已损坏： / * 。 .. * @since 4.0（方法存在于3.2，但是完全折断） * / public static< E>集合< E> removeAll（final Collection< E> collection，final Collection<？> remove）{ return ListUtils.removeAll（collection，remove）; } 不，你不疯了。 removeAll（）实际上（不正确）调用 retainAll（）。 这是 CollectionUtils 中的一个错误，影响版本3.2。已修复，但只在4.0分支中。 https://issues.apache.org/jira/browse/COLLECTIONS-349 作为进一步的证明，这里有一个指向源代码的链接： / p> http://svn.apache.org/repos/asf/commons/proper/collections/tags/COLLECTIONS_3_2/src/java/org/apache/commons/collections/CollectionUtils.java 查看此行： removeAll（Collection collection，Collection remove）{ return ListUtils.retainAll（collection，remove）; } 是的...破碎！ CollectionUtils::removeAll() Commons Collections 3.2.1I must be going crazy, becuase it seems like this method is doing the inverse of what the docs state:This little JUnit test@Testpublic void testCommonsRemoveAll() throws Exception { String str1 = "foo"; String str2 = "bar"; String str3 = "qux"; List<String> collection = Arrays.asList(str1, str2, str3); System.out.println("collection: " + collection); List<String> remove = Arrays.asList(str1); System.out.println("remove: " + remove); Collection result = CollectionUtils.removeAll(collection, remove); System.out.println("result: " + result); assertEquals(2, result.size());}Is failing with and printscollection: [foo, bar, qux] remove: [foo] result: [foo]From my reading of the docs I should expect [bar, qux]. What have I missed? 解决方案 Edit January 1, 2014 Apache Commons Collections 4.0 was finally released on November 21, 2013, and contains a fix for this issue. Link to CollectionUtils.javaLines in question (1688 - 1691), with acknowledgement the method was previously broken:/* ... * @since 4.0 (method existed in 3.2 but was completely broken) */public static <E> Collection<E> removeAll(final Collection<E> collection, final Collection<?> remove) { return ListUtils.removeAll(collection, remove);}Original AnswerNope, you're not crazy. removeAll() is actually (incorrectly) calling retainAll().This is a bug in CollectionUtils, affecting version 3.2. It's been fixed, but only in the 4.0 branch.https://issues.apache.org/jira/browse/COLLECTIONS-349And as further proof, here's a link to the source code:http://svn.apache.org/repos/asf/commons/proper/collections/tags/COLLECTIONS_3_2/src/java/org/apache/commons/collections/CollectionUtils.javaCheck out this line: public static Collection removeAll(Collection collection, Collection remove) { return ListUtils.retainAll(collection, remove);}Yep...broken! 这篇关于Java Commons Collections removeAll的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！