Java HashMap获取同步Map

HashMap是一个非同步的集合类。如果我们想对它进行线程安全的操作，那么我们必须对它进行显式同步。为了明确地同步它，java.util.Collections类的synchronizedMap()方法被用来返回一个由指定地图支持的同步（线程安全）地图。

// Get synchronized map using Collections.synchronizedMap()

Map<Integer, String> synchrMap = Collections.synchronizedMap(hmap);

**为了迭代同步地图，我们使用 **:

// Synchronized block
synchronized (synchrMap) {

      // Iterate synchronized map
      for (Map.Entry<Integer, String> entry : synchrMap.entrySet()) {

        // Print key : value
        System.out.println(entry.getKey() + " : " + entry.getValue());

      }
}

实现。

// Java Program to demonstrate how 
// to get synchronized map from HashMap
  
import java.util.*;
  
class GFG {
    public static void main(String[] args)
    {
  
        // New HashMap
        HashMap<Integer, String> hmap = new HashMap<>();
  
        // Add element to map
        hmap.put(1, "Akshay");
        hmap.put(2, "Bina");
        hmap.put(3, "Chintu");
  
        // Get synchronized map using
        // Collections.synchronizedMap()
        Map<Integer, String> synchrMap = Collections.synchronizedMap(hmap);
  
        System.out.println("Synchronized Map : ");
  
        // Synchronized block
        synchronized (synchrMap)
        {
  
            // Iterate synchronized map
            for (Map.Entry<Integer, String> entry :
                 synchrMap.entrySet()) {
  
                // Print key : value
                System.out.println(entry.getKey() + " : "
                                   + entry.getValue());
            }
        }
    }
}

输出

Synchronized Map : 
1 : Akshay
2 : Bina
3 : Chintu