java中HashMap遍历方法

来源：互联网发布：fgo淘宝石头号封号编辑：程序博客网时间：2024/05/16 01:50

在开发过程中，往往都要用到HashMap来存储数据，如何对HashMap进行遍历，今天在做项目过程中正好用到，所以写下来供大家参考。对HashMap遍历建议使用Collection类的Iterator，此类提供的方法可以方便的遍历Vector, ArrayList, LinkedList等集合元素。

1.hasNext()函数的API解释

boolean java.util.Iterator.hasNext()
boolean hasNext()

Returns true if the iteration has more elements. (In other words, returns true if next() would return an element rather than throwing an exception.)

Returns:
true if the iteration has more elements

2、next()函数的API解释

Object java.util.Iterator.next()
Returns the next element in the iteration.

Returns：the next element in the iteration

3、代码

package list.test;import java.util.ArrayList;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Map;public class ListTest {    public static HashMap<String, List<Object>> mHashMap = new HashMap<String,List<Object>>();    public static String str = "123456:78915:17896";    public static void main(String[] args){        initHashMap();    }    /*****     * 对HashMap赋值     */    public static void initHashMap(){        List<Object> mList = new ArrayList<Object>();        mList.add("qcs"+1);        mList.add("qcs"+2);        mList.add("qcs"+3);        mHashMap.put("1", mList);        List<Object> mList2 = new ArrayList<Object>();        mList2.add("jsjqcs"+1);        mList2.add("jsjqcs"+2);        mList2.add("jsjqcs"+3);        mHashMap.put("2", mList2);        List<Object> mList3 = new ArrayList<Object>();        mList3.addAll(spliteFilename(str));        mHashMap.put("3", mList3);    }    /****     * 判断key对应的值是否存在HashMap中     * @param values     * @return     */    public boolean isExit(String key){        if(mHashMap.containsKey(key)){            return true;        }        return false;    }    /*****     * 获取HashMap中对应的key值     * @param key     */    @SuppressWarnings("unchecked")    public void getHashMapValues(String key){        Iterator<?> iter = mHashMap.entrySet().iterator();        while(iter.hasNext()){            Map.Entry entry = (Map.Entry)iter.next();            String mstr = (String)entry.getKey();   //获取HashMap的key            if(mstr.equals(key)){                List<Object> list = (List<Object>)entry.getValue();//获取HashMap的key对应的值                for(int i=0;i<list.size();i++)                    System.out.println(list.get(i).toString());   //输出该HashMap中key对应的值            }        }    }    /***     * 对字符串进行分割     * @param piclist     * @return     */    public static List<Object> spliteFilename(String piclist) {        // TODO Auto-generated method stub        List<Object> list = new ArrayList<Object>();        String childStr[] = piclist.toString().split(":");        for(int i=0;i<childStr.length;i++){            list.add(childStr[i]);            System.out.println(childStr[i]);        }        return list;    }}

0 0