Java 属性和 lambda 收集
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Java Properties and lambda collect
提问by Andrea Catania
I have a method that convert Properties into hashmap in this way (i know it's wrong)
我有一个以这种方式将属性转换为哈希图的方法（我知道这是错误的）
Map<String, String> mapProp = new HashMap<String, String>();
Properties prop = new Properties();
prop.load(new FileInputStream( path ));
prop.forEach( (key, value) -> {mapProp.put( (String)key, (String)value );} );
return mapProp;
My idea is that mapping in a way like this:
我的想法是以这样的方式映射：
Properties prop = new Properties();
prop.load(new FileInputStream( path ));
Map<String, String> mapProp = prop.entrySet().stream().collect( /*I don't know*/ );
return mapProp;
How write a lambda expression for do that?
如何为此编写 lambda 表达式？
Thanks all in advance
提前谢谢大家
Andrea.
安德烈亚。
采纳答案by Lukasz Wiktor
Use Collectors.toMap
Properties prop = new Properties();
prop.load(new FileInputStream( path ));
Map<String, String> mapProp = prop.entrySet().stream().collect(
Collectors.toMap(
e -> (String) e.getKey(),
e -> (String) e.getValue()
));
回答by OldCurmudgeon
Not actually an answer but may be useful to know for others passing by.
实际上不是答案，但可能对路过的其他人有用。
Since Propertiesextends Hashtable<Object,Object>which implements Map<K,V>you should not need to do anything other than:
由于Propertiesextends Hashtable<Object,Object>which 实现，Map<K,V>你不需要做任何事情，除了：
Properties p = new Properties();
Map<String,String> m = new HashMap(p);
Not quite sure why no warnings are offered for this code as it implies a cast from Map<Object,Object>to Map<String,String>is acceptable but I suspect that is a separate question.
不太确定为什么没有为此代码提供警告，因为它意味着从Map<Object,Object>to的强制转换Map<String,String>是可以接受的，但我怀疑这是一个单独的问题。
回答by niraj.nijju
for those who want to use forEach
对于那些想要使用 forEach 的人
HashMap<String, String> propMap = new HashMap<>();
prop.forEach((key, value)-> {
propMap.put( (String)key, (String)value);
});
