先决条件:Java并发哈希图
clear()方法
java.util.concurrentHashMap.clear()方法用于清除映射。它用于从ConcurrentHashMap中删除映射。
用法:
public void clear()
// Java program to demonstrate
// clear() method
import java.util.concurrent.ConcurrentHashMap;
import java.util.*;
public class ConcurrentHashMapExample {
public static void main(String[] args)
{
// Creating a ConcurrentHashMap
Map<String, String> my_cmmap = new ConcurrentHashMap<String, String>();
// Inserting mappings in ConcurrentHashMap
// with the help of put() method
my_cmmap.put("1", "1");
my_cmmap.put("2", "1");
my_cmmap.put("3", "1");
my_cmmap.put("4", "1");
my_cmmap.put("5", "1");
my_cmmap.put("6", "1");
// Print the ConcurrentHashMap
System.out.println("Map before use of clear():\n"
+ my_cmmap);
// Now clear the map using clear()
my_cmmap.clear();
// Print the clea Map
System.out.println("Map after use of clear():"
+ my_cmmap);
}
}
输出:
Map before use of clear(): {1=1, 2=1, 3=1, 4=1, 5=1, 6=1} Map after use of clear():{}
范例2:
// Java program to demonstrate
// clear() method
import java.util.concurrent.ConcurrentHashMap;
import java.util.*;
public class ConcurrentHashMapExample {
public static void main(String[] args)
{
// Creating a ConcurrentHashMap
Map<String, String> my_map = new ConcurrentHashMap<String, String>();
// Inserting mappings in ConcurrentHashMap
// with the help of put() method
my_map.put("Geeks", "100");
my_map.put("Geek2", "150");
my_map.put("Geeks3", "120");
my_map.put("Geek4", "111");
my_map.put("Geek5", "110");
my_map.put("Geek6", "100");
// Print the ConcurrentHashMap
System.out.println("Map before use of clear():\n"
+ my_map);
// Now clear the map using clear()
my_map.clear();
// Print the cleared Map
System.out.println("Map after use of clear():"
+ my_map);
}
}
输出:
Map before use of clear(): {Geeks3=120, Geek6=100, Geek5=110, Geek4=111, Geeks=100, Geek2=150} Map after use of clear():{}
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注:本文由纯净天空筛选整理自barykrg大神的英文原创作品 Java ConcurrentHashMap | clear()。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。