Map的輸出方式總結

package package1;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

public class Demo5 {
	public static void main(String[] args) {
		Map<String, String> map=new HashMap<>();
		map.put("a", "b");
		map.put("c", "d");
		map.put("e", "f");
		map.put("g", "h");
		System.out.println(map);
		//獲取map中的鍵
		Set<String> key=map.keySet();
		for(String aa:key) {
			System.out.println(aa);
		}
		//獲取map中的值
		Collection<String> values=map.values();
		for(String value:values) {
			System.out.println(value);
		}
		//經過調用key.set()得到鍵值對 
		Set<String> keys=map.keySet();
		//利用for循環輸出
		for(String bb:keys) {
			System.out.println(bb+"--"+map.get(bb));
		}
		System.out.println("-----------------------");
		//迭代map集合的值
		Set<String> set=map.keySet();
		Iterator< String> it=set.iterator();
		while(it.hasNext()) {
			String name=it.next();
			System.out.println(name+"----"+map.get(name));
		}
		System.out.println(map.size());
		//調用Entry對象中的getKey和getValue方法就能得到鍵值對 
		Set<Entry<String,String>> entrys=map.entrySet();
		for(Entry<String,String> entry:entrys) {
			System.out.println(entry.getKey()+"---"+entry.getValue());
		}
	}
}

實例：
package package1;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class Demo4 {
public static void main(String[] args) {
	Map<Student, String> map=new HashMap<>();
	map.put(new Student("zhangsan", 20), "aa");
	map.put(new Student("lisi", 30), "bb");
	map.put(new Student("wangwu", 40), "cc");
	map.put(new Student("zhaoliu", 50), "dd");
	
	//利用for循環輸出
	for(Student aa:map.keySet()) {
	System.out.println(aa+"--"+map.get(aa));
}
	//迭代map集合的值
	Set<Student> set=map.keySet();
	Iterator<Student> it=set.iterator();
	while (it.hasNext()) {
		Student name=it.next();
		System.out.println(name+"-----"+map.get(name));
		
	}
}
}
class Student{
	String name;
	int age;
	public Student(String name,int age) {
		this.name=name;
		this.age=age;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
}

轉載：
//循環遍歷map的方法
public class MapF {
 public static void main(String[] args) {
  Map<String, Integer> tempMap = new HashMap<String, Integer>();
  tempMap.put("a","12");
  tempMap.put("b","34");
  tempMap.put("c","56");
  // JDK1.4中
  // 遍歷方法一 hashmap entrySet() 遍歷
  Iterator it = tempMap.entrySet().iterator();
  while (it.hasNext()) {
   Map.Entry entry = (Map.Entry) it.next();
   Object key = entry.getKey();
   Object value = entry.getValue();
   System.out.println("key=" + key + " value=" + value);
  }
  System.out.println("");
  // JDK1.5中,應用新特性For-Each循環
  // 遍歷方法二
  for (Map.Entry<String, Integer> entry : tempMap.entrySet()) {
   String key = entry.getKey().toString();
   String value = entry.getValue().toString();
   System.out.println("key=" + key + " value=" + value);
  }
  System.out.println("");
  // 遍歷方法三 hashmap keySet() 遍歷
  for (Iterator i = tempMap.keySet().iterator(); i.hasNext();) {
   Object obj = i.next();
   System.out.println(obj);// 循環輸出key
   System.out.println("key=" + obj + " value=" + tempMap.get(obj));
  }
  for (Iterator i = tempMap.values().iterator(); i.hasNext();) {
   Object obj = i.next();
   System.out.println(obj);// 循環輸出value
  }
  // 遍歷方法四 treemap keySet()遍歷
  for (Object o : tempMap.keySet()) {
   System.out.println("key=" + o + " value=" + tempMap.get(o));
  }
  System.out.println("11111");
  // java如何遍歷Map <String, ArrayList> map = new HashMap <String,
  // ArrayList>();
  System.out.println("java  遍歷Map <String, ArrayList> map = new HashMap<String, ArrayList>();");
  Map<String, ArrayList> map = new HashMap<String, ArrayList>();
  Set<String> keys = map.keySet();
  Iterator<String> iterator = keys.iterator();
  while (iterator.hasNext()) {
   String key = iterator.next();
   ArrayList arrayList = map.get(key);
   for (Object o : arrayList) {
    System.out.println(o);
   }
  }
  Map<String, List> map = new HashMap<String, List>();
  for (Map.Entry entry : map.entrySet()) {
   String key = entry.getKey().toString();
   List<String> list= (List) entry.getValue();
   for (String value : list) {
    System.out.println(key + "====" + value);
   }
  }
 }
}