java基礎(chǔ)增強(qiáng)講解：增強(qiáng)for循環(huán)取Map值

import?static?java.lang.System.out;//靜態(tài)導(dǎo)入

import?java.util.HashMap;
import?java.util.Iterator;
import?java.util.LinkedHashMap;
import?java.util.List;
import?java.util.ArrayList;
import?java.util.Map;
import?java.util.Map.Entry;
import?java.util.Set;

import?org.junit.Test;
public?class?Demo1?{

	/**
	?*?@param?args
	?*/
	public?static?void?main(String[]?args)?{
	
	}
	@Test
	public?void?test1(){
		int?arr[]={1,2,3,4};
		for(int?i:arr){
			System.out.print(i+"?");
		}
	}
	
	@Test
	public?void?test2(){
		
		//傳統(tǒng)方式1，通過key取出value
		
		Map?mp=new?HashMap();?//無序輸出
		mp=new?LinkedHashMap();?//正序存入正序輸出
		mp.put("1",?"a");
		mp.put("2",?"b");
		mp.put("3",?"c");
	
		Set?set=mp.keySet();
		Iterator?it=set.iterator();
		while(it.hasNext()){
			String?key=(String)it.next();
			String?value=(String)mp.get(key);
			System.out.println(key+"="+value);
		}
	}
	
	@Test
	public?void?test3(){
		
		//傳統(tǒng)方式2，通過?鍵值對?去取出
		
		Map?mp=new?HashMap();?//無序輸出
		mp=new?LinkedHashMap();?//正序存入正序輸出
		mp.put("1",?"a");
		mp.put("2",?"b");
		mp.put("3",?"c");
		
		Set?set=mp.entrySet();
		Iterator?it=set.iterator();
		while(it.hasNext()){
			Map.Entry?entry=(Entry)it.next();
			String?key=(String)?entry.getKey();
			String?value=(String)?entry.getValue();
			System.out.println(key+"="+value);
		}
	}
	
	@Test
	public?void?test4(){
		Map?mp=new?HashMap();?//無序輸出
		mp=new?LinkedHashMap();?//正序存入正序輸出
		mp.put("1",?"a");
		mp.put("2",?"b");
		mp.put("3",?"c");
		
		//增強(qiáng)for循環(huán)取map的第一種方式(Map不能迭代)
		for(Object?obj:mp.keySet()){
			String?key=(String)obj;
			String?value=(String)mp.get(key);
			System.out.println(key+"="+value);
		}
	}
	
	@Test
	public?void?test5(){
		Map?mp=new?HashMap();?//無序輸出
		mp=new?LinkedHashMap();?//正序存入正序輸出
		mp.put("1",?"a");
		mp.put("2",?"b");
		mp.put("3",?"c");
		
		//增強(qiáng)for循環(huán)取map的第二種方式(Map不能迭代)
		for(Object?obj:mp.entrySet()){
			Map.Entry?entry=(Entry)obj;
			String?key=(String)entry.getKey();
			String?value=(String)entry.getValue();
			System.out.println(key+"="+value);
		}
	}
}