JAVA学习笔记(六)几个学习容器的简单例子

1,学了许多理伦，发现最好的解决办法还是多敲代码！
例1，向ArrayList中插入一个数据：

import java.util.ArrayList;
 public class AddExample {

	public static void main(String[] args) {
      ArrayList<String> alist=new ArrayList<String>();
      alist.add("2");
      alist.add("7");
      alist.add("9");
      
      alist.add(1,"4");
      for(String s:alist)
    	  System.out.println(s);
	}

}

Output:
2
INSERTED
7
9

例2:ArrayList的简单操作：

 import java.util.ArrayList;
public class ArrayListDemo {
	public static void main(String[] args) {
      ArrayList al=new ArrayList();
      System.out.println("al的大小:"+al.size());
      //向arrayList中添加元素
      al.add("C");
      al.add("S");
      al.add("A");
      al.add("F");
      al.add("B");
      al.add("D");
      al.add(1,"A2");
      System.out.println("添加后的大小:"+al.size());
      //显示所有的arrayList
      System.out.println("显示al:"+al);
      //从中移除一个元素
      al.remove("F");
      al.remove(2);
      System.out.println("移除后的大小:"+al.size());
      System.out.println("显示移除部分元素后的al:"+al);
	}

}

output:
al的大小:0
添加后的大小:7
显示al:[C, A2, S, A, F, B, D]
移除后的大小:5
显示移除部分元素后的al:[C, A2, A, B, D]

例3:简单操作List, Set, SortedSet, LinkedHashSet, Map, LinkedHashMap

import java.util.*;
public class CollectionExample {
	public static void main(String[] args) {
		List l=new LinkedList();
		l.add("List:angel");
		l.add("schildt");
		l.add("mathew");
		l.add("schildt");
		print(l);
		
		Set s=new HashSet();
		s.add("Set:rose");
		s.add("schildt");
		s.add("mathew");
		s.add("schildt");
		print(s);
		
		SortedSet ss=new TreeSet();
		ss.add("Set:jasmine");
		ss.add("schildt");
		ss.add("mathew");
		ss.add("schildt");
		print(ss);
		
		LinkedHashSet sss=new LinkedHashSet();
		sss.add("set:winslet");
		sss.add("schildt");
		sss.add("mathew");
		sss.add("schildt");
		print(sss);
		
		Map<String,String> m1=new HashMap<String,String>();
		m1.put("map", "map:HashMap");
		m1.put("schildt", "java2");
		m1.put("mathew", "hyden");
		m1.put("schildt", "java2s");
		print(m1.keySet());
		print(m1.values());
		
		SortedMap<String,String> sm=new TreeMap<String,String>();
		sm.put("map", "treeMap:treeMap");
		sm.put("schildt", "java2");
		sm.put("mathew", "hyden");
		sm.put("schildt", "java2s");
		print(sm.keySet());
		print(sm.values());
		
		LinkedHashMap<String,String> lm=new LinkedHashMap<String,String>();
		lm.put("map", "LinkedHashMap:LinkedHashMap");
		lm.put("schildt", "java2");
		lm.put("mathew", "hyden");
		lm.put("schildt", "java2s");
		print(lm.keySet());
		print(lm.values());
	}

	/**
	 * @param l
	 */
	private static void print(Collection coll) {
		Iterator iter=coll.iterator();
		while(iter.hasNext())
		{
			String elem=(String)iter.next();
			System.out.print(elem+" ");
		}
		System.out.println(" ");
	}

}

Output:
schildt Set:rose mathew 
Set:jasmine mathew schildt 
set:winslet schildt mathew 
schildt mathew map 
java2s hyden map:HashMap 
map mathew schildt 
treeMap:treeMap hyden java2s 
map schildt mathew 
LinkedHashMap:LinkedHashMap java2s hyden