JAVA容器小结
时间:2010-01-06
JAVA中的容器提供了非常完善的方法来保存对象，你可以使用这些工具来解决大数据量的问题。下面是笔者在开发中用到过的一些容器总结如此。
1 ArrayList
使用ArrayList非常简单：创建一个实例，用add()插入对象，然后用get()访问这些对象，此时需要索引，就象数组一样，但是不需要方括号，ArrayList还有size()方法，从而可以知道ArrayList的大小，也可以避免因为越界而引发错误。另外，ArrayList长于随机访问元素，但是在List的中间插入和移处元素时较慢。下面是ArrayList的例子(来自thinking in java)：
/**//*
* @(#)AppleAndOrangesWithGenerics.java 1.0 May 17, 2008
* @author:Administrator
* Copyright 2008 CSS WEB Microsystems, Inc. All rights reserved.
* CSS WEB ROOM PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package holding;
import java.util.ArrayList;
public class AppleAndOrangesWithGenerics ...{
public static void main(String[] args) ...{
ArrayList<Apple> apples = new ArrayList<Apple>();
for(int i = 0; i < 3; i++) ...{
apples.add(new Apple());
}
for(int i = 0; i < apples.size(); i++)
System.out.println(((Apple)apples.get(i)).id());
for(Apple c:apples)
System.out.println(c.id()+"-");
}
}
/**//*
* @(#)ListFeatures.java 1.0 May 17, 2008
* @author:Administrator
* Copyright 2008 CSS WEB Microsystems, Inc. All rights reserved.
* CSS WEB ROOM PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package holding;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Random;
import typeinfo.pets.*;
public class ListFeatures ...{
public static void main(String[] args) ...{
Random rand = new Random(47);
List<Pet> pets = Pets.arrayList(7);
System.out.print("1: " + pets);
System.out.println();
Hamster h = new Hamster();
pets.add(h);
System.out.print("2: " + pets);
System.out.println();
System.out.print("3: " + pets.contains(h));
System.out.println();
pets.remove(h);
Pet p = pets.get(2);
System.out.print("4: " + pets.indexOf(p));
System.out.println();
Pet cymric = new Cymric();
System.out.print("5: " + pets.indexOf(cymric));
System.out.println();
System.out.print("6: " + pets.remove(cymric));
System.out.println();
System.out.print("7: " + pets.remove(p));
System.out.println();
System.out.print("8: " + pets);
System.out.println();
pets.add(3,new Mouse());
System.out.print("9: " + pets);
System.out.println();
List<Pet> sub = pets.subList(1,4);
System.out.print("sublist: " + sub);
System.out.println();
System.out.print("10: " + pets.containsAll(sub));
System.out.println();
Collections.sort(sub);
System.out.print("sorted sublist: " + sub);
System.out.println();
System.out.print("11: " + pets.containsAll(sub));
System.out.println();
Collections.shuffle(sub, rand);
System.out.print("shuffle sublist: " + sub);
System.out.println();
System.out.print("12: " + pets.containsAll(s
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