java-map复合类型(HashMap-TreeMap)常用操作例子(适合初学者)

时间:2021-09-20 21:31:57
package com.net.xinfang.reflect;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.TreeMap; /***
* map-HashMap/HashTable/TreeMap
*
* @author xinfang
*
*/
public class map006 {
public void map() {
Map<Integer, String> map = new HashMap<Integer, String>();
/***
* TreeMap的entrySet比keySet遍历效率高
*/
Map<String,String> treemap=new TreeMap<String,String>();
Map<String,String> ht=new Hashtable<String,String>();
ht.put(String.valueOf(1),String.valueOf(1));
for(int i=0;i<2;i++){
treemap.put(String.valueOf(i),String.valueOf(i));
}
Iterator<Entry<String,String>> tree=treemap.entrySet().iterator();
while(tree.hasNext()){
System.out.println(tree.next());
}
map.put(0, "0");// 添加key-value
map.put(1, "1");
//循环添加key-value
for(int i=2;i<10;i++){
Integer key=i;
String value=String.valueOf(i);
map.put(key, value);
}
// keyset遍历-泛型-Iterator接口
Iterator<Integer> it = map.keySet().iterator();
while (it.hasNext()) {
System.out.println(it.next());
}
// entrykey遍历-泛型-Iterator接口
Iterator<Entry<Integer, String>> its = map.entrySet().iterator();
while (its.hasNext()) {
System.out.println(its.next().getValue());
}
// 第二种for-entry
for (Map.Entry<Integer, String> entry : map.entrySet()) {
System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}
// 遍历map中的键
for (Integer key : map.keySet()) {
System.out.println("Key = " + key);
}
// 遍历map中的值
for (String value : map.values()) {
System.out.println("Value = " + value);
}
System.out.println(map.get(1));// 获取键值为1的值
System.out.println(map.size());// 获取map大小
System.out.println(map.equals(1));// 判断对象的内容是否相同
System.out.println(map.hashCode());// 获取hashcode
System.out.println(map.isEmpty());// 空-true,非空-false
System.out.println(map.remove(1));// 移除键值为1的值
System.out.println(map.values());// 获取值
System.out.println(map.getClass());// 获取类名
System.out.println(map.replace(0, "2"));// 替换键值为0的值为2
System.out.println(map.toString());// 转换为字符串
// map转换为List
List<Integer> keyList = new ArrayList(map.keySet());
List<String> valueList = new ArrayList(map.values());
List<Entry> entryList = new ArrayList(map.entrySet());
// for遍历输出
for (Integer key : keyList) {
System.out.println(key);
}
for (String value : valueList) {
System.out.println(value);
}
for (Entry entry : entryList) {
System.out.println(entry);
}
}
public void searchList(String name) {
LinkedList<String> list = new LinkedList<String>();// 链表对象
list.add("1");// 添加元素
list.add("2");
list.add("3");
list.push(name);// 入栈
list.pop();// 出栈
for (int i = 0; i < list.size(); i++) {
if (name.equals(list.get(i))) {
System.out.println("您要查询的信息存在!" + list.getFirst() + list.getLast());
}
}
if (list.contains(name)) {
System.out.println("您要查询的信息存在!");
}
}
public static void main(String args[]) {
map006 m6 = new map006();
m6.map();
m6.searchList("2");
}
}