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

 

 

 

 

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=\t 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()+"\tvalue:"+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=\t 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() + "\tvalue:" + 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