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目录HashMap方法 Map.getOrDefault()解读解释实例总结HashMap方法 Map.getOrDefault()解读 HashMap getOrDefault(k
HashMap getOrDefault(key, defaultValue) method in Java with Examples
The getOrDefault(Object key, V defaultValue) method of Map interface, implemented by HashMap class is used to get the value mapped with specified key. If no value is mapped with the provided key then the default value is returned.
Syntax:
default V getOrDefault(Object key, V defaultValue)Parameters: This method accepts two parameters:
Return Value: This method returns value mapped with the specified key, otherwise default value is returned.
意思就是当Map集合中有这个key时，就使用这个key值，如果没有就使用默认值defaultValue
Program 1：
// Java program to demonstrate
// getOrDefault(Object key, V defaultValue) method
import java.util.*;
public class GFG {
// Main method
public static void main(String[] args)
{
// Create a HashMap and add some values
HashMap<String, Integer> map
= new HashMap<>();
map.put("a", 100);
map.put("b", 200);
map.put("c", 300);
map.put("d", 400);
// print map details
System.out.println("HashMap: "
+ map.toString());
// provide key whose value has to be obtained
// and default value for the key. Store the
// return value in k
int k = map.getOrDefault("b", 500);
// print the value of k returned by
// getOrDefault(Object key, V defaultValue) method
System.out.println("Returned Value: " + k);
}
} Output：
HashMap: {a=100, b=200, c=300, d=400}
Returned Value: 200
Program 2：
// Java program to demonstrate
// getOrDefault(Object key, V defaultValue) method
import java.util.*;
public class GFG {
// Main method
public static void main(String[] args)
{
// Create a HashMap and add some values
HashMap<String, Integer> map
= new HashMap<>();
map.put("a", 100);
map.put("b", 200);
map.put("c", 300);
map.put("d", 400);
// print map details
System.out.println("HashMap: "
+ map.toString());
// provide key whose value has to be obtained
// and default value for the key. Store the
// return value in k
int k = map.getOrDefault("y", 500);
// print the value of k returned by
// getOrDefault(Object key, V defaultValue) method
System.out.println("Returned Value: " + k);
}
} Output:
HashMap: {a=100, b=200, c=300, d=400}
Returned Value: 500
以上为个人经验，希望能给大家一个参考，也希望大家多多支持编程网。
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本文标题: HashMap方法之Map.getOrDefault()解读及案例
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