Collection、List、Set、Map关系图学习笔记1

/**
*
*/
package com.undergrowth.util;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Stack;

import org.junit.Test;

/**
* 测试集合操作
*
* @author Administrator
*
*/
public class CollectionTest {

/**
* 泛型方法 对实现Iterable<E>接口的对象进行迭代
*
* @param iterable
*/
public <E> void iterator(Iterable<E> iterable) {
for (E e : iterable) {
System.out.println(e);
}
}

// 测试数组
private final String[] ITEMS = { "中国", "美国", "德国", "法国" };

/**
* 创建ArrayList集合
*
* @return
*/
private Collection<String> createArrayList() {
Collection<String> collection = new ArrayList<String>();
addData(collection);
return collection;
}

/**
* 向数组中添加元素
*
* @param collection
*/
private void addData(Collection<String> collection) {
// TODO Auto-generated method stub
collection.addAll(Arrays.asList(ITEMS));
}

/**
* 测试ArrayList可变数组
*/
@Test
public void testArrayList() {
Collection<String> collection = createArrayList();
iterator(collection);
System.out.println("删除后，在进行迭代");
collection.remove("中国");
iterator(collection);
System.out.println("测试是否包含中国:" + collection.contains("中国"));
System.out.println("测试清除集合:");
collection.clear();
iterator(collection);
System.out.println("测试清除集合后，是否为空:" + collection.isEmpty());
addData(collection);
iterator(collection);
System.out.println("填充数据后，转换为数组");
System.out.println("数组元素个数:" + collection.toArray().length);
System.out.println("截取子列表,[0,2)");
iterator(((List<String>) collection).subList(0, 2));
}

/**
* 创建堆栈元素
*
* @return
*/
private Stack<String> createStack() {
// TODO Auto-generated method stub
Stack<String> stack = new Stack<>();
stack.push(ITEMS[0]);
stack.push(ITEMS[1]);
stack.push(ITEMS[2]);
return stack;
}

/**
* 测试堆栈 先进后出
*/
@Test
public void testStack() {
Stack<String> stack = createStack();
iterator(stack);
System.out.println("判断堆栈是否为空:" + stack.empty());
System.out.println("查找堆栈元素的位置:" + stack.search("中国"));
System.out.println("查看栈顶元素:" + stack.peek());
System.out.println("删除栈顶元素:" + stack.pop());
}

/**
* 创建Set集合
*
* @return
*/
private Set<String> createSet() {
// TODO Auto-generated method stub
Set<String> set = new HashSet<>();
set.add(ITEMS[0]);
set.add(ITEMS[0]);
set.add(ITEMS[0]);
set.add(ITEMS[1]);
set.add(ITEMS[2]);
set.add(ITEMS[3]);
return set;
}

/**
* 测试HashSet
*/
@Test
public void testHashSet() {
Set<String> set = createSet();
iterator(set);
}

/**
* 创建Map 键值对
*
* @return
*/
private Map<String, String> createMap() {
// TODO Auto-generated method stub
Map<String, String> map = new HashMap<String, String>();
map.put(ITEMS[0], ITEMS[0]);
map.put(ITEMS[0], ITEMS[0]);
map.put(ITEMS[1], ITEMS[1]);
map.put(ITEMS[2], ITEMS[2]);
map.put(ITEMS[3], ITEMS[3]);
return map;
}

/**
* 测试HashMap
*/
@Test
public void testHashMap() {
Map<String, String> map = createMap();
iterator(map.keySet());
iterator(map.values());
}

}