-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathMapTest.java
More file actions
44 lines (34 loc) · 1.22 KB
/
MapTest.java
File metadata and controls
44 lines (34 loc) · 1.22 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
package Chapter13ConnectionInterface;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
public class MapTest {
public static void main(String[] args) {
//Map的实现类有HashMap，和TreeMap，HashMap效率较高，如果不需要按顺序访问，则用HashMap
//桶大小----填装因子
Map<Integer,String> maps=new HashMap<>(3, (float) 0.75);
maps.put(1, "tom");
maps.put(2, "jack");
maps.put(3, "alice");
System.out.println(maps);
//Iterator所有条目
for(Map.Entry<Integer,String> entry:maps.entrySet()){
Integer key=entry.getKey();
String value=entry.getValue();
System.out.println(key+":"+value);
}
//LinkedHashMap---链表映射表
//实现“最近最少使用”原则-----
Map<String,String> cache=new LinkedHashMap<String,String>(128, 0.75F, true){
//重写此方法---每当方法返回true时，就添加一个新条目，从而到时删除eldest条目
protected boolean removeEldestEntry(Map.Entry<String, String> eldest){
return size()>100;
}
};
//同步视图
Map<String,String> synMap=Collections.synchronizedMap(new HashMap<String,String>());
//插入时检查类型
Map<String,String> checkedMap= Collections.checkedMap(new HashMap<>(), String.class,String.class);
}
}