map遍历的几种方式

我就是我 2021-10-01 00:26 568阅读 0赞

1、通过map.entrySet( )遍历：

Map<String, String> map = new HashMap<String, String>();  
for (int i = 0; i < 4; i++) \{  
String s = "数字" + i;  
map.put("zhi-" + i, s);  
\}  
Set<Entry<String, String>> s = map.entrySet();  
int size = s.size();  
for(Map.Entry<String,String> entry:map.entrySet()) \{  
String value =entry.getValue();  
String key = entry.getKey();  
System.out.println("key:"+key+",value:"+value);  
\}

输出结果为：

key:zhi-0,value:数字0  
key:zhi-1,value:数字1  
key:zhi-2,value:数字2  
key:zhi-3,value:数字3

2、通过map.keySet()及map.value（）遍历：

Map<String, String> map = new HashMap<String, String>();  
for (int i = 0; i < 4; i++) \{  
String s = "数字" + i;  
map.put("zhi-" + i, s);  
\}

for (String key : map.keySet()) \{  
System.out.println(key);  
\}  
for(String value:map.values()) \{  
System.out.println(value);  
\}

输出结果为：

zhi-0  
zhi-1  
zhi-2  
zhi-3  
数字0  
数字1  
数字2  
数字3

3、使用 Iterator遍历：

Map<String, String> map = new HashMap<String, String>();  
for (int i = 0; i < 4; i++) \{  
String s = "数字" + i;  
map.put("zhi-" + i, s);  
\}

Iterator<Map.Entry<String, String>> entries = map.entrySet().iterator();  
while (entries.hasNext()) \{  
Map.Entry<String, String> data = entries.next();  
System.out.println("key:" + data.getKey() + ",value:" + data.getValue());  
\}

输出结果为：

key:zhi-0,value:数字0  
key:zhi-1,value:数字1  
key:zhi-2,value:数字2  
key:zhi-3,value:数字3

4、通过map.get（key）遍历：

Map<String, String> map = new HashMap<String, String>();  
for (int i = 0; i < 4; i++) \{  
String s = "数字" + i;  
map.put("zhi-" + i, s);  
\}

for(String key:map.keySet()) \{  
String value = map.get(key);  
System.out.println(key+" "+value);  
\}

输出结果为：

zhi-0 数字0  
zhi-1 数字1  
zhi-2 数字2  
zhi-3 数字3

转载于:https://www.cnblogs.com/qqzhulu/p/10367117.html