java Collection接口和Collections类的层次关系图，类图

￡神魔★判官ぃ 2022-08-05 02:18 237阅读 0赞

首先来看看Collection和Collections的区别，Collection和Collections是完全不同的两个概念。Collections是个java.util下的类，它包含有各种有关集合操作的静态方法。 Collection是个java.util下的接口，它是各种集合结构的父接口。

Collections在java中的关系图：

![Center][]

Collection是各种集合的接口，来看看下边这个层次结构：![Center 1][]

还有map的层次结构：

![Center 2][]

示例代码：

package com.zz.chain;
    
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.HashSet;
    import java.util.LinkedList;
    import java.util.List;
    import java.util.Map;
    import java.util.Set;
    /**
     * 代码示例
     * Copyright 2015年5月31日
     * created by txxs
     * all right reserved
     */
    public class Test {
    	public static void main(String[] args) {
    		List<String> a1 = new ArrayList<String>();
    		a1.add("Program");
    		a1.add("Creek");
    		a1.add("Java");
    		a1.add("Java");
    		System.out.print("ArrayList Elements：");
    		System.out.print(a1 + "\n");
    		 
    		List<String> l1 = new LinkedList<String>();
    		l1.add("Program");
    		l1.add("Creek");
    		l1.add("Java");
    		l1.add("Java");
    		System.out.print("LinkedList Elements：");
    		System.out.print(l1 + "\n");
    		 
    		Set<String> s1 = new HashSet<String>(); // or new TreeSet() will order the elements;
    		s1.add("Program");
    		s1.add("Creek");
    		s1.add("Java");
    		s1.add("Java");
    		s1.add("tutorial");
    		System.out.print("Set Elements：");
    		System.out.print(s1 + "\n");
    		 
    		Map<String, String> m1 = new HashMap<String, String>(); // or new TreeMap() will order based on keys
    		m1.put("Windows", "2000");
    		m1.put("Windows", "XP");
    		m1.put("Language", "Java");
    		m1.put("Website", "programcreek.com");
    		System.out.print("Map Elements：");
    		System.out.print(m1);
    	}
    }

运行结果：

![Center 3][]

参考：http://stackoverflow.com/questions/3317381/what-is-the-difference-between-collection-and-list-in-java

[Center]: /images/20220805/80fb8d7c2f3e49d68eb5348bdb2a976f.png
[Center 1]: /images/20220805/5986e43e296d449fbce58e9484eab404.png
[Center 2]: /images/20220805/a0db5c092cf44e1d9e1ff45cdf565d4d.png
[Center 3]: /images/20220805/b55102bec5a9406996736f559fc76016.png