import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Map.Entry; import java.util.Set; /** * JavaLoopTest * * @author www.trinea.cn 2013-10-28 */ public class JavaLoopTest {
Loop through the items of a HashMap with a for-each loop.Note: Use the keySet() method if you only want the keys, and use the values() method if you only want the values:ExampleGet your own Java Server // Print keys for (String i : capitalCities.keySet()) { System.out.println(...
package cn.trinea.java.test; import java.text.DecimalFormat; import java.util.Calendar; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Map.Entry; import java.util.Set; /** * JavaLoopTest * * @author www.trinea.cn 2013-10-28 */ public class...
package cn.trinea.java.test; import java.text.DecimalFormat; import java.util.Calendar; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Map.Entry; import java.util.Set; /** * JavaLoopTest * * @author www.trinea.cn 2013-10-28 */ public class...
In this post we will see different ways we can iterate through a map ,HashMapandTreeMApin Java. There are following ways for iterating map in java. Using EntrySet() and for each loop – In this way we Iterate Map Entries (Keys and Values) with the help for each loop ...
With forEach we iterate over all pairs of the map. Iteration with enhanced for loopThe enhanced for loop can be used to iterate over a HashMap. Main.java import java.util.HashMap; import java.util.Map; void main() { Map<String, String> capitals = new HashMap<>(); capitals.put("...
Loop Through a HashMap Loop through the items of aHashMapwith afor-eachloop. Note:Use thekeySet()method if you only want the keys, and use thevalues()method if you only want the values: Example // Print keysfor(Stringi:capitalCities.keySet()){System.out.println(i);} ...
}/*It just traversed the values, not the keys*/privatestaticvoidpartForEachTraversal(Map<String, Object>map){ System.out.println("\nUse values to loop, can only traverse values, not keys");longstart = System.currentTimeMillis();for(Object value :map.values()) { ...
//iteration over map using for each loop for(Map.Entryentry: hm.entrySet()) { //getting keys and values using method System.out.println(entry.getKey() + " = " +entry.getValue()); } /*---TreeMap implementation---*/ Map tm=new TreeMap(); //adding...
ConcurrentHashMap是J.U.C(java.util.concurrent包)的重要成员,它是HashMap的一个线程安全的、支持高效并发的版本。在默认理想状态下,ConcurrentHashMap可以支持16个线程执行并发写操作及任意数量线程的读操作。本文将结合Java内存模型,分析JDK源代码,探索ConcurrentHashMap高并发的具体实现机制,包括其在JDK中的定义和结构...