System.out.println("播放器列表 (之后): " + playerArray);

}

/**

* 对 ArrayList 进行排序.

*/

void sort() {

System.out.println("排序前： " + playerArray);

Collections.sort(bookArray);

System.out.println("排序后： " + playerArray);

}

/**

* 反转 ArrayList.

*/

void reverse() {

System.out.println("反转前： " + playerArray));

Collections.reverse(bookArray);

System.out.println("反转后： " + playerArray));

}

void copy() {

System.out.println("playerArray 是否为空？ " + playerArray.isEmpty());

System.out.println("playerArray （之前）： " + playerArray);

bookCopyObj = new ArrayList(bookArray);

System.out.println("otherListObj （之后）： " + otherListObj);

}

}

class PlayerListTest {

public static void main(String[] args) {

PlayersList playerObj = new PlayersList();

playerObj.add();

playerObj.display();

playerObj.search();

playerObj.extract();

playerObj.shuffle();

playerObj.sort();

playerObj.reverse();

playerObj.copy();

}

}

4.2LinkedList类 方法addLast(); removeFirst(); getFirst();获得队列第一个元素.

输出: [dog, dog, cat, aat, Aat, b4] [dog, cat, b4, Aat, aat] 是随机的顺序

4.3 HashMap类 键值对照表

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import java.util.*;

public class PrintingContainers {

static Map fill(Map m) {

m.put("dog2", "Bosco"); //dog2是key,Bosco是value 用Map.Entry来取键值

m.put("dog", "Spot");

m.put("cat", "Rags");

return m;

}

public static void main(String[] args) {

System.out.println(fill(new HashMap()));

}

}

import java.util.*;

public class PrintingContainers {

static Map fill(Map m) {

m.put("dog2", "Bosco"); //dog2是key,Bosco是value 用Map.Entry来取键值

m.put("dog", "Spot");

m.put("cat", "Rags");

return m;

}

public static void main(String[] args) {

System.out.println(fill(new HashMap()));

}

}

输出: {dog2=Bosco, dog=Spot, cat=Rags}

5. Vector类

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import java.util.Vector;

class PreciousStones {

Vector preciousVector;

PreciousStones() {

preciousVector = new Vector();

}

void add() {

preciousVector.addElement("翡翠");

preciousVector.addElement("黄晶");

preciousVector.addElement("绿宝石");

preciousVector.addElement("祖母绿");

}

void insert() {

preciousVector.insertElementAt("钻石" , 0);

preciousVector.insertElementAt("猫眼石" , 4);

}

void display(String title) {

int count = 0;

while (count < preciousVector.size()) {

System.out.print(preciousVector.elementAt(count));

count++;

if (count < preciousVector.size()) {

System.out.print(", ");

}

}

}

void search() {

if (preciousVector.contains("钻石")) {

System.out.println("在索引 " + preciousVector.indexOf("钻石") + " 中找到钻石");

}

}

void remove() {

preciousVector.removeElement("黄晶");

System.out.println("删除黄晶后的内容: ");

int count = 0;

while (count < preciousVector.size()) {

System.out.print(preciousVector.elementAt(count));

count++;

if (count < preciousVector.size()) {

System.out.print(", ");

}

}

}

void otherDetails() {

System.out.println("\n第一个元素 = " + preciousVector.firstElement());

System.out.println("默认容量 = " + preciousVector.capacity());

}

}

class PreciousStoneTest {

public static void main(String [] args) {

PreciousStones objPrecious = new PreciousStones();

objPrecious.add();

objPrecious.display("显示内容");

objPrecious.insert();

objPrecious.display("显示插入后的内容");

objPrecious.search();