一、HashMap的初始化1、HashMap 初始化的文艺写法 HashMap 是一种常用的数据结构,一般用来做数据字典或者 Hash 查找的容器。普通青年一般会这么初始化: HashMap<String, String> map = new HashMap<Str…
HashMap< String, String> map = new HashMap< String, String>() { { put("Name", "June"); put("QQ", "2572073701"); } }; } System.out.println(System.currentTimeMillis() - st); // 1217 */for(int i =0; i <10000000; i++) {HashMap<String,String> map =newHashMap<String,Str...
Hashtable<String, String> htable=new Hashtable<>(); 第二部分: CopyOnWriteArrayList<String> coarray=new CopyOnWriteArrayList<>(); ArrayList<String> array=new ArrayList<>(); Vector<String> vec=new Vector<>(); 第三部分: StringBuffer sb=new StringBuffer(); StringBuilder sbu=new StringBuilder();...
Map<String, String> map = new HashMap<String, String>(); map.put("hollis","hollischuang"); Class<?> mapType = map.getClass(); Method capacity = mapType.getDeclaredMethod("capacity"); capacity.setAccessible(true); System.out.println("capacity : "+ capacity.invoke(map)); Fieldsize= m...
HashMap<String, String> map = new HashMap<>(); String k = "王羲之"; String v = "大书法家"; map.put(k, v); Field field = map.getClass().getDeclaredField("table"); field.setAccessible(Boolean.TRUE); Object[] nodes = (Object[]) field.get(map); ...
HashMap<String,String>map=newHashMap<String,String>();map.put("Name","June");map.put("QQ","2572073701"); 看完这段代码,很多人都会觉得这么写太啰嗦了,对此,文艺青年一般这么来了: 代码语言:javascript 复制 HashMap<String,String>map=newHashMap<String,String>(){{put("Name","June");put("...
Map<String, String> h = new HashMap<String, String>() {{ put("a","b"); }}; 但是,您应该小心并确保您理解上面的代码(它创建了一个继承自 HashMap 的新类)。因此,您应该在这里阅读更多内容: http ://www.c2.com/cgi/wiki?DoubleBraceInitialization ,或者简单地使用 Guava: Map<String, Integer...
HashMap<String, String>Sites=newHashMap<String, String>(); // 添加键值对 Sites.put("one","Google"); Sites.put("two","Runoob"); Sites.put("three","Taobao"); Sites.put("four","Zhihu"); System.out.println(Sites); } } 执行以上代码,输出结果如下: ...
public static void main(String[] args) { int aHundredMillion = 10000000;Map map = new HashMap<>(); long s1 = System.currentTimeMillis(); for (int i = 0; i < ahundredmillion;="" i++)=""> map.put(i, i); } long s2 = System.currentTimeMillis(); ...