{"id":1174,"date":"2016-08-18T17:39:06","date_gmt":"2016-08-18T09:39:06","guid":{"rendered":"http:\/\/www.yeetrack.com\/?p=1174"},"modified":"2016-08-18T23:05:10","modified_gmt":"2016-08-18T15:05:10","slug":"%e8%b5%b0%e8%bf%91guava%e4%b8%89-%e9%9b%86%e5%90%88","status":"publish","type":"post","link":"https:\/\/www.yeetrack.com\/?p=1174","title":{"rendered":"\u8d70\u8fd1Guava(\u4e09): \u96c6\u5408"},"content":{"rendered":"
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\u96c6\u5408\uff1a<\/h1>\n

FluentIterable\u7c7b\uff1a<\/h2>\n
    \n
  • \u4f7f\u7528<\/span>FluentIterable.filter<\/span>\u8fc7\u6ee4, \u5373\u5229\u7528<\/span>Predicate<\/span>\u5b9e\u73b0\uff1a<\/span><\/li>\n<\/ul>\n

    <\/p>\n

    Iterable<Person> adults = FluentIterable.from(ps).filter(\n\tnew Predicate<Person>() {\n\t\t@Override\n\t\tpublic boolean apply(Person p) {\n\t\t\treturn p.getAge() >= 18; \/\/ \u5e74\u9f84>18\n\t\t}\n\t});<\/code><\/pre>\n
      \n
    • \u4f7f\u7528<\/span>FluentIterable.transform()<\/span>\u8f6c\u6362\uff0c\u5373\u5229\u7528<\/span>Function<\/span>\u5b9e\u73b0\uff1a<\/span><\/li>\n<\/ul>\n
      FluentIterable.from(ps).transform(new Function<Person, String>() {\n\t@Override\n\tpublic String apply(Person p) {\n\t     return Joiner.on('#').join(p.getName(), p.getAge());\n\t}\n});<\/code><\/pre>\n
      Lists\u7c7b\uff1a<\/h2>\n
        \n
      • \u4f7f\u7528Lists.newArrayList<\/span>\u521b\u5efa\u5217\u8868\uff1a<\/span><\/li>\n<\/ul>\n
        ps = Lists.newArrayList(\n\tnew Person(\"person1\", 22),\n\tnew Person(\"person2\", 23),\n\tnew Person(\"person3\", 17)\n);<\/code><\/pre>\n
          \n
        • \u4f7f\u7528Lists.partition()<\/span>\u65b9\u6cd5\u5206\u5272\u5217\u8868\uff1a<\/span><\/li>\n<\/ul>\n
          \/\/[a, b, c, d, e] --> [[a, b], [c, d, e]] -\nList<List<Person>> subList = Lists.partition(ps, 2);<\/code><\/pre>\n
          Sets\u7c7b\uff1a<\/h2>\n
            \n
          • Sets.difference()\u6c42<\/span>S1-S2<\/li>\n<\/ul>\n
            Set<String> s1 = Sets.newHashSet(\"1\", \"2\", \"3\");\nSet<String> s2 = Sets.newHashSet(\"2\", \"3\", \"4\");\nSets.difference(s1, s2); \/\/[1]<\/code><\/pre>\n
              \n
            • Sets.intersection()<\/span>\u6c42S1,S2\u4ea4\u96c6<\/span><\/li>\n<\/ul>\n
              Set<String> s1 = Sets.newHashSet(\"1\", \"2\", \"3\");\nSet<String> s2 = Sets.newHashSet(\"3\", \"2\", \"4\");\nSets.SetView<String> sv = Sets.intersection(s1, s2); \/\/ [2, 3]<\/code><\/pre>\n
                \n
              • Sets.union()<\/span>\u6c42\u5408\u96c6
                \n<\/span><\/li>\n<\/ul>\n
                Set<String> s1 = Sets.newHashSet(\"1\", \"2\", \"3\");\nSet<String> s2 = Sets.newHashSet(\"3\", \"2\", \"4\");\nSets.SetView<String> sv = Sets.union(s1, s2); \/\/ [3, 2, 1 ,4]<\/code><\/pre>\n
                Maps\u7c7b\uff1a<\/h2>\n
                  \n
                • Maps.uniqueIndex()<\/span>\u5c06\u5217\u8868\u8f6c\u6362\u4e3amap<\/span><\/li>\n<\/ul>\n
                  \/\/iterator\u5404\u4e2a\u5143\u7d20\u4f5c\u4e3aMap.values, key\u4e3aFunction.apply\u8fd4\u56de\u503c\nMaps.uniqueIndex(ps.iterator(), new Function<Person, String>() {\n\t@Override\n\tpublic String apply(Person p) {\n\t\treturn p.getName();\n\t}\n});<\/code><\/pre>\n
                    \n
                  • Maps.asMap()<\/span>\uff0c<K, V>\u548cMaps.uniqueIndex()\u76f8\u53cd<\/span><\/li>\n<\/ul>\n
                    Maps.asMap(ps, new Function<Person, String>() {\n\t@Override\n\tpublic String apply(Person p) {\n\t\treturn p.getName();\n\t}\n});<\/code><\/pre>\n
                      \n
                    • Maps Transform API<\/span>:<\/span><\/li>\n<\/ul>\n
                      Maps.transformEntries(map, new Maps.EntryTransformer<String, Boolean, String>() {\n\u00a0\u00a0\u00a0\u00a0@Override\n\u00a0\u00a0\u00a0\u00a0public String transformEntry(String key, Boolean value) {\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0return value ? \"yes\" : \"no\";\n\u00a0\u00a0\u00a0\u00a0}\n}); \u5c06Map<String, Boolean> --> Map<String, String>, \u5176\u4ed6\u7684\u8fd8\u6709Maps.transformValues\u8f6c\u6362\u503c<\/code><\/pre>\n
                      Multimaps:<\/h2>\n
                        \n
                      • \u4e00\u4e2akey<\/span>\u5bf9\u5e94\u591a\u4e2avalue<\/span>\u3002<\/span><\/li>\n<\/ul>\n
                        ArrayListMultiMap:<\/h3>\n
                        ArrayListMultimap<String, String> multiMap = ArrayListMultimap.create();\nmultiMap.put(\"Foo\", \"1\");\nmultiMap.put(\"Foo\", \"2\");\nmultiMap.put(\"Foo\", \"3\");\nSystem.out.println(multiMap); \/\/ {Foo=[1,2,3]}<\/code><\/pre>\n
                        \u5f53\u51fa\u73b0\u91cd\u590d\u503c\u65f6\uff0c\u4f9d\u7136\u4f1a\u88ab\u6dfb\u52a0\uff0c\u56e0\u4e3aArrayListMultiMap\u7684value\u65f6\u4e00\u4e2aArrayList:<\/p>\n
                        ArrayListMultimap<String, String> multiMap = ArrayListMultimap.create();\nmultiMap.put(\"Bar\", \"1\");\nmultiMap.put(\"Bar\", \"2\");\nmultiMap.put(\"Bar\", \"3\");\nmultiMap.put(\"Bar\", \"3\");\nmultiMap.put(\"Bar\", \"3\");\nSystem.out.println(multiMap); \/\/{Bar=[1, 2, 3, 3, 3]}\uff0c\u76f8\u540c\u7684value\u4f1a\u91cd\u590d\uff0cvalue\u5185\u90e8\u662f\u4e00\u4e2aList<\/code><\/pre>\n
                        HashMultiMap:<\/h2>\n
                        HashMultimap<String, String> multiMap = HashMultimap.create();\nmultiMap.put(\"Bar\", \"1\");\nmultiMap.put(\"Bar\", \"2\");\nmultiMap.put(\"Bar\", \"3\");\nmultiMap.put(\"Bar\", \"3\");\nmultiMap.put(\"Bar\", \"3\");\nSystem.out.println(multiMap); \/\/{Bar=[3, 2, 1]}, \u76f8\u540c\u7684value\u4e0d\u4f1a\u91cd\u590d\uff0cvalue\u5185\u90e8\u662f\u4e00\u4e2aSet<\/code><\/pre>\n
                        \u5176\u4ed6\u4e00\u4e9bMultiMap:<\/p>\n
                        LinkedHashMultimap \/\/\u987a\u5e8f\u7684HashMultimap, \u5f62\u5982LinkedHashMap\nTreeMultimap \/\/\u53ef\u6392\u5e8f\u7684MultiMap, \u5f62\u5982TreeMap\n\/\/\u4e00\u4e9b\u4e0d\u53ef\u53d8\u7684map\nImmutableListMultimap\nImmutableMultimap\nImmutableSetMultimap<\/code><\/pre>\n
                        BiMap:<\/h2>\n
                          \n
                        • \u5176\u9650\u5236value\u662f\u552f\u4e00\u7684<\/span>\uff0c\u4e14\u901a\u8fc7value\u53ef\u4ee5\u627e\u5230key<\/span><\/span><\/li>\n<\/ul>\n
                          BiMap<String,String> biMap = HashBiMap.create();\nbiMap.put(\"1\",\"Tom\");         \nbiMap.put(\"2\",\"Tom\"); \/\/\u629b\u51fa\u5f02\u5e38<\/code><\/pre>\n
                            \n
                          • BiMap.forcePut()<\/span>\u5f3a\u5236\u653e\u5165value\u76f8\u7b49\u7684entry:<\/span><\/li>\n<\/ul>\n
                            BiMap<String, String> biMap = HashBiMap.create();\nbiMap.put(\"1\", \"Tom\");\nbiMap.forcePut(\"2\", \"Tom\");\nSystem.out.println(biMap); \/\/{2=Tom}<\/code><\/pre>\n
                              \n
                            • BiMap.inverse()<\/span>\u53cd\u8f6ckey-value<\/span><\/li>\n<\/ul>\n
                              BiMap<String, String> biMap = HashBiMap.create();\nbiMap.put(\"1\", \"Tom\");\nbiMap.put(\"2\", \"Harry\");\nBiMap<String, String> inverseMap = biMap.inverse();\nSystem.out.println(biMap); \/\/{2=Harry, 1=Tom}\nSystem.out.println(inverseMap); \/\/{Harry=2, Tom=1<\/code><\/pre>\n
                              Table:<\/h2>\n
                                \n
                              • \u5b83\u5177\u67092\u4e2akey[\u884c, \u5217]<\/span>\uff0c\u5bf9\u5e94\u4e00\u4e2a\u503c<\/span>\u3002<\/span><\/li>\n<\/ul>\n
                                HashBasedTable:<\/h3>\n
                                  \n
                                • \u901a\u7528\u64cd\u4f5c<\/span><\/li>\n<\/ul>\n
                                  HashBasedTable<Integer, Integer, String> table = HashBasedTable.create();\ntable.put(1, 1, \"Rook\");\ntable.put(1, 2, \"Knight\");\ntable.put(1, 3, \"Bishop\");\nSystem.out.println(table.contains(1, 1)); \/\/true\nSystem.out.println(table.containsColumn(2)); \/\/true\nSystem.out.println(table.containsRow(1)); \/\/true\nSystem.out.println(table.containsValue(\"Rook\")); \/\/true\nSystem.out.println(table.remove(1, 3)); \/\/Bishop\nSystem.out.println(table.get(3, 4)); \/\/null<\/code><\/pre>\n
                                    \n
                                  • Table views<\/span>\uff0c\u8868\u884c\u5217\u89c6\u56fe<\/span><\/li>\n<\/ul>\n
                                    Map<Integer,String> columnMap = table.column(1);\nMap<Integer,String> rowMap = table.row(2);<\/code><\/pre>\n
                                      \n
                                    • \u5176\u4ed6table<\/span><\/li>\n<\/ul>\n
                                      ArrayTable \/\/\u4e8c\u7ef4\u6570\u7ec4\u5b9e\u73b0\nImmutableTable \/\/\u4e0d\u53ef\u53d8table\uff0c\u521b\u5efa\u540e\u4e0d\u80fd\u6539\u53d8\nTreeBasedTable \/\/\u5bf9\u884c\u5217\u6392\u5e8f\u7684table<\/code><\/pre>\n
                                      Range:<\/h2>\n
                                        \n
                                      • \u4ee3\u8868\u4e00\u79cd\u8303\u56f4\u7684\u7c7b\u3002<\/span><\/li>\n<\/ul>\n
                                        Range<Integer> numberRange = Range.closed(1, 10); \/\/\u5305\u62ec\u9996\u5c3e\nSystem.out.println(numberRange.contains(10)); \/\/true\nSystem.out.println(numberRange.contains(1)); \/\/true\n\t\t\nRange<Integer> numberRange1 = Range.open(1,10); \/\/\u9664\u53bb\u9996\u5c3e\nSystem.out.println(numberRange1.contains(10)); \/\/false\nSystem.out.println(numberRange1.contains(1)); \/\/false<\/code><\/pre>\n
                                          \n
                                        • Ran<\/span>ge<\/span>\u548cFunction<\/span>\u7ec4\u5408\u6210Predicate<\/span>\u7684\u8fc7\u6ee4\u6761\u4ef6<\/span><\/li>\n<\/ul>\n
                                          Range<Integer> ageRange = Range.closed(35, 50);\n\/\/Person\u5230age\u8f6c\u6362\u7684function\nFunction<Person, Integer> ageFunction = new Function<Person, Integer>() {\n\t@Override\n\tpublic Integer apply(Person person) {\n\t\treturn person.getAge();\n\t}\n};\n\/\/\u8fd9\u6837\u5f97\u5230\u5e74\u9f84\u518d[35, 50]\u4e4b\u95f4\u7684\u4eba\nPredicate<Person> predicate = Predicates.compose(ageRange,ageFunction);<\/code><\/pre>\n
                                            \n
                                          • \u521b\u5efa\u4e0d\u53ef\u53d8<\/span>\u7684\u96c6\u5408<\/span><\/li>\n<\/ul>\n
                                            MultiMap<Integer,String> map = new ImmutableListMultimap.Builder<Integer,String>()\n   \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0.put(1,\"Foo\").putAll(2,\"Foo\",\"Bar\",\"Baz\")\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0.putAll(4,\"Huey\",\"Duey\",\"Luey\")\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0.put(3,\"Single\").build();<\/code><\/pre>\n
                                            Ordering:<\/h2>\n
                                              \n
                                            • Ordering\u63d0\u4f9b\u4e86\u4e00\u4e9b\u7b80\u5355\u5f3a\u5927\u7684\u6392\u5e8f\u529f\u80fd\u3002<\/span><\/li>\n<\/ul>\n
                                              \/**\n * \u57ce\u5e02\u4eba\u53e3\u6bd4\u8f83\u5668\n *\/\npublic class CityByPopluation implements Comparator<City> {\n\t@Override\n\tpublic int compare(City city1, City city2) {\n\t\treturn Ints.compare(city1.getPopulation(), city2.getPopulation());\n\t}\n}<\/code><\/pre>\n
                                                \n
                                              • \u53cd\u5e8f<\/span><\/li>\n<\/ul>\n
                                                Ordering.from(cityByPopluation).reverse();<\/code><\/pre>\n
                                                  \n
                                                • \u5904\u7406Null<\/span><\/li>\n<\/ul>\n
                                                  Ordering.from(comparator).nullsFirst();\/\/null\u503c\u6700\u5c0f\u653e\u5728\u524d\u9762<\/code><\/pre>\n
                                                    \n
                                                  • \u4e8c\u6b21\u6392\u5e8f<\/span><\/li>\n<\/ul>\n
                                                    \/**\n * \u96e8\u91cf\u6bd4\u8f83\u5668\n *\/\npublic class CityByRainfall implements Comparator<City> {\n\t@Override\n\tpublic int compare(City city1, City city2) {\n\t\treturn Doubles.compare(city1.getAverageRainfall(),\n\t\t\t\tcity2.getAverageRainfall());\n\t}\n}<\/code><\/pre>\n
                                                    Ordering<City> secondaryOrdering = Ordering.from(cityByPopulation).compound(cityByRainfall);\/\/\u7ec4\u5408\u6bd4\u8f83\u5668\nCollections.sort(cities,secondaryOrdering); \/\/\u6392\u5e8f<\/code><\/pre>\n
                                                      \n
                                                    • \u83b7\u53d6\u6700\u5927\u6700\u5c0f<\/span><\/li>\n<\/ul>\n
                                                      Ordering<City> ordering = Ordering.from(cityByPopluation);\nList<City> topFive = ordering.greatestOf(cityList,5); \/\/\u524d5\u4e2a\nList<City> bottomThree = ordering.leastOf(cityList,3); \/\/\u6700\u540e3\u4e2a<\/code><\/pre>\n
                                                      \u770b\u6765Guava\u5728\u96c6\u5408\u65b9\u9762\u8fd8\u662f\u5f88\u7ed9\u529b\u7684\u3002<\/p>\n
                                                      \n
                                                      \u8d70\u8fd1Guava(\u4e00): \u57fa\u672c\u5de5\u5177<\/a><\/p><\/blockquote>\n