1.按插入顺序排序 LinkedHashMap
Map<String, String> map = new LinkedHashMap<String, String>();
map.put("11", "value1");
map.put("zame", "value2");
map.put("name", "value3");
map.put("3", "value4");
//第一种:普遍使用,二次取值
System.out.println("通过Map.keySet遍历key和value:");
for (String key : map.keySet()) {
System.out.println("key= "+ key + " and value= " + map.get(key));
}
结果:
通过Map.keySet遍历key和value:
key= 11 and value= value1
key= zame and value= value2
key= name and value= value3
key= 3 and value= value4
2.按key hash值排序 HashMap
Map<String, String> map = new HashMap<String, String>();
map.put("11", "value1");
map.put("zame", "value2");
map.put("name", "value3");
map.put("3", "value4");
//第二种
System.out.println("通过Map.entrySet使用iterator遍历key和value:");
Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
while (it.hasNext()) {
Map.Entry<String, String> entry = it.next();
System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
}
结果:
通过Map.entrySet使用iterator遍历key和value:
key= 11 and value= value1
key= 3 and value= value4
key= zame and value= value2
key= name and value= value3
3.按key值排序 TreeMap
Map<String, String> map = new TreeMap<String, String>();
map.put("11", "value1");
map.put("zame", "value2");
map.put("name", "value3");
map.put("3", "value4");
//第三种:推荐,尤其是容量大时
System.out.println("通过Map.entrySet遍历key和value");
for (Map.Entry<String, String> entry : map.entrySet()) {
System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
}
结果
通过Map.entrySet遍历key和value
key= 11 and value= value1
key= 3 and value= value4
key= name and value= value3
key= zame and value= value2
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