怎么遍历Map集合中的对象？

Question

import java.util.*;

public class TestMap {
public static void main(String[] args) {
Map map=new TreeMap();
map.put(1,new Elent(1,2));
map.put(2,new Elent(2,0));
map.put(3,new Elent(5,1));
map.put(4,new Elent(7,1));
printKeyValuePairs(map);

}

public static void printValues(Map map){
    Collection vs=map.values();
    Iterator it=vs.iterator();
    while(it.hasNext()){
        System.out.println(it.next());
    }
}

public static void printKeyValuePairs(Map map){
    Set ks=map.keySet();
    Iterator it=ks.iterator();
    while(it.hasNext()){
        Object key=it.next();
        Object value=map.get(key);
        System.out.println(key+"  "+value);
    }
}

}
class Elent{
int id,index;
public Elent(int id,int index){
this.id=id;
this.index=index;
}
public int getId(){
return id;
}
public int getIndex(){
return index;
}
}

怎么取KEY值为I的对象ID的值是否为0？

Answer 1

[code="java"]

import java.util.*;

public class TestMap {
public static void main(String[] args) {
Map map = new TreeMap();
map.put(1, new Elent(1, 2));
map.put(2, new Elent(2, 0));
map.put(3, new Elent(5, 1));
map.put(4, new Elent(7, 1));
printKeyValuePairs(map);
}

public static void printValues(Map map) {
    Collection vs = map.values();
    Iterator it = vs.iterator();
    while (it.hasNext()) {
        System.out.println(it.next());
    }
}

public static void printKeyValuePairs(Map map) {
    Set ks = map.keySet();
    Iterator it = ks.iterator();
    while (it.hasNext()) {
        Object key = it.next();
        [color=red]//这里进行强制转换存在map里的value的类型啊
        Elent value = (Elent)map.get(key);

        System.out.println(key + "  " + value.getId());[/color]
    }
}

}

class Elent {
int id, index;

public Elent(int id, int index) {
    this.id = id;
    this.index = index;
}

public int getId() {
    return id;
}

public int getIndex() {
    return index;
}

}

[/code]