Java 基础一些代码练习笔记（HashMap）

package com.lee;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;

public class MapTest3
{
public static void main(String[] args)
{
HashMap map = new HashMap();

map.put("a", "aa");
map.put("b", "bb");
map.put("c", "cc");
map.put("d", "dd");
map.put("e", "ee");

Set set = map.keySet();

for(Iterator iter = set.iterator(); iter.hasNext();)
{
String key = (String)iter.next();
String value = (String)map.get(key);

System.out.println(key + "=" + value);
}

}
}

package com.lee;

import java.util.HashMap;

public class MapTest1
{
public static void main(String[] args)
{
HashMap map = new HashMap();

map.put("a", "zhangsan");
map.put("b", "lisi");
map.put("c", "wangwu");
map.put("a", "zhaoliu");

String value = (String)map.get("b");
System.out.println(value);
System.out.println("------------------");

String value2 = (String)map.get("d");
System.out.println(value2);
}

}

import java.util.Map;
import java.util.Set;

public class MapTest5
{
public static void main(String[] args)
{
HashMap map = new HashMap();

map.put("a", "aa");
map.put("b", "bb");
map.put("c", "cc");
map.put("d", "dd");

Set set = map.entrySet();

for (Iterator iter = set.iterator(); iter.hasNext();)
{
Map.Entry entry = (Map.Entry)iter.next();

String key = (String)entry.getKey();
String value = (String)entry.getValue();

System.out.println(key + ":" + value);
}

}
}