Java List&Map简单初始化方法

Java中List与Map初始化的一些写法 

 

// InitCollections.java - sample of init collect

package com.util;

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

/**
 *
 */
public class InitCollections
{

    /**
     * @param args
     */
    public static void main(final String[] args)
    {
        // add items into list with add method
        final List<Object> list = new ArrayList<Object>()
        {
            {
                add("obj1");
                add("obj2");
                add("objN");
            }
        };

        for (final Object item : list)
        {
            System.out.println(item);
        }
        System.out.println();

        // add items into list with arrays
        final ArrayList<String> listFromArray = new ArrayList(Arrays.asList("Ryan", "Julie", "Bob"));

        for (final Object item : listFromArray)
        {
            System.out.println(item);
        }
        System.out.println();

        // add values into HashMap when create
        final Map<String, Object> map = new HashMap<String, Object>()
        {
            {
                put("key1", "value1");
                put("key2", "value2");
                put("keyN", "valueN");
            }
        };

        for (final String key : map.keySet())
        {
            System.out.println("key=" + key + "\tvalue=" + map.get(key));
        }
        System.out.println();

        final Set<String> set = new HashSet<String>()
        {
            {
                add("setString1");
                add("setString2");
                add("setString3");
                add("setString1");
            }
        };

        for (final String item : set)
        {
            System.out.println("item=" + item);
        }
    }
}

 

参考文章：http://www.cnblogs.com/alibai/p/3523517.html