JDK类集框架实验（ArrayList，LinkedList，TreeSet，HashSet，TreeMap，HashMap）

Posted 2021-01-17 caiyishuai

 

 

 

 

ArrayList

import java.util.ArrayList;
public class C8_3 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        ArrayList<Integer> nl = new ArrayList<Integer>();
        nl.add((Integer) 1);
        nl.add((Integer) 2);
        nl.add((Integer) 3);
        System.out.println("输出集合的所有元素" + nl);
        System.out.println("输出下标为2的元素: " + nl.get(2));
        nl.add(1, (Integer) 4);// 下标1的位置插入一个元素
        System.out.println("元素下标1的位置插入4后，输出所有元素" + nl);
        Integer b = (Integer) 1;
        int n = nl.indexOf(b);// 查找指定元素的下标
        nl.remove(n);// 删除指定下标的元素
        System.out.println("n=" + n + "   删除n元素后输出集合中所有元素");
        for(Integer i : nl){
            System.out.print(i + " , ");
        }

        System.out.println();
    }

}

 

 

LinkedList

import java.util.LinkedList;

public class C8_5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        
        LinkedList queue = new LinkedList();
        
        queue.offer("a1");// 入队列操作 queue.add()
        queue.offer("a2");
        queue.offer("a3");
        
        System.out.println(queue);        
        System.out.println(queue.poll());// 出队列操作 queue.pop()
        System.out.println(queue);
        System.out.println(queue.peek()); // 取队列头元素操作,并没有把元素踢掉
        System.out.println(queue);
        System.out.println(queue.poll()); // 出队列操作
        System.out.println(queue.isEmpty()); // 判断队列空操作


    }

}

 

TreeSet

import java.util.Iterator;
import java.util.TreeSet;

public class TestTreeSet {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        
        TreeSet ts1 = new TreeSet();
        
        ts1.add(20);
        ts1.add(20);
        ts1.add(50);
        ts1.add(30);
        ts1.add(100);
        ts1.add(10);
        ts1.add(70);
        ts1.add(60);
        System.out.println("树里面的元素"+ts1);
        System.out.println(ts1.isEmpty());
        System.out.println(ts1.size()+" ");
        System.out.println(ts1.contains(30));
        ts1.remove(30);
        System.out.println(ts1.contains(30));
        System.out.println(ts1.size());
        
        // 迭代器的使用方法
        Iterator it = ts1.iterator();
        while(it.hasNext())
            System.out.println(it.next() + " ");
        System.out.println();
        
        Object[] data = ts1.toArray();
        for(int i=0; i<data.length; i++)
            System.out.print(data[i]+" ");
        System.out.println();
    }

}

 

HashSet

import java.util.*;

public class TestHashSet {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        HashSet ts1 = new HashSet();
        ts1.add(20);
        ts1.add(50);
        ts1.add(30);
        ts1.add(100);
        ts1.add(10);
        ts1.add(70);
        ts1.add(60);
        ts1.add(30);
        System.out.println(ts1);
        System.out.println(ts1.isEmpty());
        System.out.println(ts1.size());
        System.out.println(ts1.contains(30));
        ts1.remove(30);
        System.out.println(ts1.contains(30));
        System.out.println(ts1.size());

        // 迭代器的使用方法
        Iterator it = ts1.iterator();
        while (it.hasNext())
            System.out.print(it.next() + "  ");
        System.out.println();

        // toArray方法的使用
        Object[] data = ts1.toArray();
        for (int i = 0; i < data.length; i++)
            System.out.print(data[i] + "  ");
        System.out.println();

    }

}

 

 TreeMap

import java.util.*;

public class TestTreeMap {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        
        TreeMap register = new TreeMap();
        register.put("zhangshan","jingsp");
        register.put("lishi","1996-8");
        register.put("wangwu","960515");
        register.put("zhaoliu","overS");
        
          System.out.println("-------------------");
          System.out.println("entryset =");
          Set s = register.entrySet();
          Iterator it = s.iterator();
          
          while(it.hasNext())
          {          
               System.out.println(it.next());
          }
          
          System.out.println("-------------------");
          System.out.println("key=	   value=");
          Set s0 = register.entrySet();
          Iterator it0 = s0.iterator();
          while(it0.hasNext())
          {
              Map.Entry map = (Map.Entry)it0.next();
              System.out.println("key:"+map.getKey()+"	value:"+map.getValue());
          }
          
          System.out.println("-------------------");
          System.out.println("keyset ====");
          Set s1 = register.keySet();
          Iterator it1 = s1.iterator();
          while(it1.hasNext())
              System.out.println(it1.next());

          System.out.println("-------------------");
          System.out.println("valueset ====");
          Collection s2=register.values();
          Iterator it2=s2.iterator();
          while(it2.hasNext())
              System.out.println(it2.next());   
          
          System.out.println("-------------------");
          
          System.out.println(register.size());
          System.out.println(register.get("lishi"));
          System.out.println(register.isEmpty());
          register.put("chengjiu", "arg1");
          System.out.println(register.size());
          System.out.println(register.remove("chengjiu"));
          System.out.println(register.size());
          System.out.println(register.containsKey("chengjiu"));   System.out.println(register.containsValue("960515"));


          

    }

}

 

Map接口内部定义了一个接口Entry

interface Entry{
    Object getKey();
    Object getValue();
    Object setValue();
    boolean equals(Object value);
    int hashCode();
}

 

 

HashMap

import java.util.*;
public class TestHashMap {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        HashMap register = new HashMap();
        register.put("zhangshan", "jingsp");
        register.put("lishi", "1996-8");
        register.put("wangwu", "960515");
        register.put("zhaoliu", "overS");
        
        System.out.println(register);
        
        System.out.println("-------------------");
        System.out.println("entryset =");
        Set s = register.entrySet();
        
        System.out.println("hashCode " + s.hashCode());
        
        Iterator it = s.iterator();
        while(it.hasNext())
            System.out.println(it.next());
        
        System.out.println("-------------------");
        System.out.println("key=	   value=");
        Set s0 = register.entrySet();
        Iterator it0 = s.iterator();
        while (it0.hasNext()) {
            Map.Entry map = (Map.Entry) it0.next();
            System.out.println("key:" + map.getKey() + "	value:"
                    + map.getValue());
        }

        
        System.out.println("-------------------");
        System.out.println("keyset ====");
        Set s1 = register.keySet();
        Iterator it1 = s1.iterator();
        while (it1.hasNext())
            System.out.println(it1.next());

        System.out.println("-------------------");
        System.out.println("valueset ====");
        Collection s2 = register.values();
        Iterator it2 = s2.iterator();
        while (it2.hasNext())
            System.out.println(it2.next());

        
    }

}

{lishi=1996-8, zhangshan=jingsp, zhaoliu=overS, wangwu=960515}
-------------------
entryset =
hashCode 48127692
lishi=1996-8
zhangshan=jingsp
zhaoliu=overS
wangwu=960515
-------------------
key= value=
key:lishi value:1996-8
key:zhangshan value:jingsp
key:zhaoliu value:overS
key:wangwu value:960515
-------------------
keyset ====
lishi
zhangshan
zhaoliu
wangwu
-------------------
valueset ====
1996-8
jingsp
overS
960515