分享一个两种优雅的方式迭代Map代码 - 黑马程序员技术交流社区

package io.shaoshuai.colletion;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/**
* MapOperation.java
* @author shaoshuai
* created 2015年2月3日下午2:22:26
* @version 1.0
*/
public class MapOperation {
/**
* main
* @param args
* void
* @exception
* @since 1.0.0
*/
public static void main(String[] args) {
Map<String, User> map = new HashMap<String ,User>();
User user = new User.UserBuilder(1l, "lanmotbzy", "123456")
.email("1025276114@qq.com").address("北京黑马").build();
User user2 = new User.UserBuilder(2l, "shaoshuai", "123456")
.email("shaoshuai@qq.com").address("中关村").build();
map.put("1", user);
map.put("2", user2);
// 迭代map第一种方式：轮询所有的key
System.out.println("迭代map第一种方式：轮询所有的key");
for(Iterator<String> keys = map.keySet().iterator();keys.hasNext();) {
user = map.get(keys.next());
System.out.println("user.getId():" + user.getId());
System.out.println("user.getUsername():" + user.getUsername());
System.out.println("user.getPassword():" + user.getPassword());
System.out.println("user.getEmail():" + user.getEmail());
System.out.println("user.getAddress():" + user.getAddress());
}
// 迭代map第二种方式轮询所有的Map.Entry<K,V>
Map.Entry<String, User> entry;
System.out.println("迭代map第二种方式轮询所有的Map.Entry<K,V>");
for(Iterator<Map.Entry<String, User>> entrys = map.entrySet().iterator();entrys.hasNext();) {
entry = entrys.next();
user = entry.getValue();
System.out.println("user.getId():" + user.getId());
System.out.println("user.getUsername():" + user.getUsername());
System.out.println("user.getPassword():" + user.getPassword());
System.out.println("user.getEmail():" + user.getEmail());
System.out.println("user.getAddress():" + user.getAddress());
}
System.out.println("System.nanoTime():" + System.nanoTime());
}
}

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