本文介绍了最好的Java5种遍历HashMap数据的写法，分享给大家，也给自己留一个笔记，具体如下：
通过EntrySet的迭代器遍历
Iterator < Entry < Integer, String >> iterator = coursesMap.entrySet().iterator();
while (iterator.hasNext()) {
Entry < Integer, String > entry = iterator.next();
System.out.print(entry.getKey() + ". ");
System.out.println(entry.getValue());
}
输出结果如下：
zzw:how_iterate_hashmap_in_java zzw$ java IterateHashMapExample 1
TIOBE Index for March 2020:
1. Java
2. C
3. Python
4. C++
5. C#
6. Visual Basic .NET
7. JavaScript
8. PHP
9. SQL
10. GO
通过KeySet的迭代器遍历
Iterator < Integer > iterator = coursesMap.keySet().iterator();
while (iterator.hasNext()) {
Integer key = iterator.next();
System.out.print(key + ". ");
System.out.println(coursesMap.get(key));
}
输出结果如下：
zzw:how_iterate_hashmap_in_java zzw$ java IterateHashMapExample 2
TIOBE Index for March 2020:
1. Java
2. C
3. Python
4. C++
5. C#
6. Visual Basic .NET
7. JavaScript
8. PHP
9. SQL
10. GO
通过ForEach循环遍历
for (Map.Entry < Integer, String > entry: coursesMap.entrySet()) {
System.out.print(entry.getKey() + ". ");
System.out.println(entry.getValue());
}
输出结果如下：
zzw:how_iterate_hashmap_in_java zzw$ java IterateHashMapExample 3
TIOBE Index for March 2020:
1. Java
2. C
3. Python
4. C++
5. C#
6. Visual Basic .NET
7. JavaScript
8. PHP
9. SQL
10. GO
通过Lambda表达式遍历
coursesMap.forEach((key, value) -> {
System.out.print(key + ". ");
System.out.println(value);
});
输出结果如下：
zzw:how_iterate_hashmap_in_java zzw$ java IterateHashMapExample 4
TIOBE Index for March 2020:
1. Java
2. C
3. Python
4. C++
5. C#
6. Visual Basic .NET
7. JavaScript
8. PHP
9. SQL
10. GO
通过Stream API遍历
coursesMap.entrySet().stream().forEach((entry) -> {
System.out.print(entry.getKey() + ". ");
System.out.println(entry.getValue());
});
输出结果如下：
zzw:how_iterate_hashmap_in_java zzw$ java IterateHashMapExample 5
TIOBE Index for March 2020:
1. Java
2. C
3. Python
4. C++
5. C#
6. Visual Basic .NET
7. JavaScript
8. PHP
9. SQL
10. GO
完整示例代码在这里
