Java Map遍历的六种方式

	public static void f1() {
		for(String key : map.keySet()) {
			System.out.println(key+"\t"+map.get(key));
		}
	}

	public static void f2() {
		Iterator iterator = map.keySet().iterator();
		while(iterator.hasNext()) {
			String key = iterator.next();
			System.out.println(key+"\t"+map.get(key));
		}
	}

	public static void f3() {
		Set> entrySet = map.entrySet();
		for(Map.Entry set : entrySet) {
			System.out.println(set.getKey()+"\t"+set.getValue());
		}
	}

	public static void f4() {
		Iterator> iterator = map.entrySet().iterator();
		while(iterator.hasNext()) {
			Entry entry = iterator.next();
			System.out.println(entry.getKey()+"\t"+entry.getValue());
		}
	}

	public static void f5() {
		map.forEach(new BiConsumer() {
			@Override
			public void accept(String t, Integer u) {
				System.out.println(t+"\t"+u);
			}
		});
	}

	public static void f6() {
		map.forEach((key,value)->System.out.println(key+"\t"+value));
	}

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.TreeMap;
import java.util.function.BiConsumer;

public class MainTest {

//	private static Map map = new HashMap();// 无序的
	private static Map map = new TreeMap();// 有序的
	
	static {
		for(int i = 0 ; i < 10 ; i++) {
			map.put("key"+i, i);
		}
	}
	
	public static void main(String[] args) {
		f1();
//		f2();
//		f3();
//		f4();
//		f5();
//		f6();
	}
	// 1、map.keySet()取得key的set集合，foreach遍历
	public static void f1() {
		for(String key : map.keySet()) {
			System.out.println(key+"\t"+map.get(key));
		}
	}
	// 2、map.keySet()取得key的set集合，Iterator游标迭代
	public static void f2() {
		Iterator iterator = map.keySet().iterator();
		while(iterator.hasNext()) {
			String key = iterator.next();
			System.out.println(key+"\t"+map.get(key));
		}
	}
	// 3、map.entrySet()方法把map转成Set，foreach遍历
	public static void f3() {
		Set> entrySet = map.entrySet();
		for(Map.Entry set : entrySet) {
			System.out.println(set.getKey()+"\t"+set.getValue());
		}
	}
	// 4、map.entrySet()方法把map转成Set，Iterator遍历
	public static void f4() {
		Iterator> iterator = map.entrySet().iterator();
		while(iterator.hasNext()) {
			Entry entry = iterator.next();
			System.out.println(entry.getKey()+"\t"+entry.getValue());
		}
	}
	// 5、map.forEach + 函数式编程
	public static void f5() {
		map.forEach(new BiConsumer() {
			@Override
			public void accept(String t, Integer u) {
				System.out.println(t+"\t"+u);
			}
		});
	}
	// 6、map.forEach + lambda 表达式
	public static void f6() {
		map.forEach((key,value)->System.out.println(key+"\t"+value));
	}
	
}