首先寫一個實體類User.java

package domain;
/**
 * @author twc
 *
 */
public class User {
private int id;
private String name;


public int getId() {
return id;
}


public void setId(int id) {
this.id = id;
}


public String getName() {
return name;
}


public void setName(String name) {
this.name = name;
}


}

  然後寫一個ListMapTest.java

  ipackage execise;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;


import domain.User;


/**
 * @author twc
 * 
 */
public class ListMapTest {


/**
* @param args
*/
public static void main(String[] args) {

List<Map<String, Object>> list = test();
for (int i = 0; i < list.size(); i++) {
Map map = list.get(i);
Set set = map.keySet();
Object[] str = set.toArray();
for (int j = 0; j < str.length; j++) {
Object obj = map.get(str[j]);
if (obj instanceof User) {
User user = (User) obj;
System.out.println(user.getName() + "," + user.getId());
map.remove(str[j]);
}
}
}


}


public static List<Map<String, Object>> test() {
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
User user = new User();
user.setId(1);
user.setName("zhangsan");
list.add(add(user, "aa"));
user.setId(2);
user.setName("lisi");
list.add(add(user, "bb"));
return list;
}


public static Map<String, Object> add(User user, String str) {
Map<String, Object> map = new HashMap<String, Object>();
map.put(str, user);
return map;


}
}

看上面是往Map裡壓入兩次，兒值打印出

lisi 2

lisi 2

目前還不清楚 為何 只有打印出lisi來，zhangsna為何打印不出來，