blocks|key|1977960|text|第一件事，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1977961|1977962|属性类基于哈希表，而不是哈希表。Properties类基本上扩展了Hashtable|blockquote|1977963|1977964|1977965|在HashMap类中没有这样的构造函数，它接受一个属性对象并返回一个hashmap对象。所以你所做的是不正确的。您应该能够将属性的对象转换为哈希表引用。|1977966|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|M|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|N|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|O|8|@]|9|@]|A|$]]|$1|G|3|-4|5|6|7|P|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|Q|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|R|8|@]|9|@]|A|$]]]|K|$]]

First thing, 

<blockquote>
 Properties class is based on Hashtable and not Hashmap. Properties class basically extends Hashtable
</blockquote>

There is no such constructor in HashMap class which takes a properties object and return you a hashmap object. So what you are doing is NOT correct. You should be able to cast the object of properties to hashtable reference.

blocks|key|4102893|text|这是因为Properties+extends+Hashtable+(反过来实现了Map<Object,+Object>)。您尝试将其输入到Map<String,+String>中。因此它是不兼容的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4102894|您需要将字符串属性一个接一个地输入到您的映射中...|4102895|例如：|4102896|for+(final+String+name:+properties.stringPropertyNames())
++++map.put(name,+properties.getProperty(name));|code-block|syntax|javascript|4102897|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/7/docs/api/java/util/Properties.html^0|4|A|N|9|14|J|1X|J|4|S|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]|$9|13|A|14|B|C]]|D|@$9|15|A|16|1|17]]|E|$]]|$1|F|3|G|5|6|7|18|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|19|8|@]|D|@]|E|$]]|$1|J|3|K|5|L|7|1A|8|@]|D|@]|E|$M|N]]|$1|O|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

This is because <a href="http://docs.oracle.com/javase/7/docs/api/java/util/Properties.html"><code>Properties</code> extends <code>Hashtable&lt;Object, Object&gt;</code></a> (which, in turn, implements <code>Map&lt;Object, Object&gt;</code>). You attempt to feed that into a <code>Map&lt;String, String&gt;</code>. It is therefore incompatible.

You need to feed string properties one by one into your map...

For instance:

<pre><code>for (final String name: properties.stringPropertyNames())
 map.put(name, properties.getProperty(name));
</code></pre>

blocks|key|672650|text|Properties实现的是Map<Object,+Object>，而不是Map<String,+String>。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|672651|您正在尝试调用此构造函数：|672652|public+HashMap(Map<?+extends+K,?+extends+V>+m)|code-block|syntax|javascript|672653|..。其中K和V都是String。|672654|但是Map<Object,+Object>不是Map<?+extends+String,+?+extends+String>。它可以包含非字符串键和值。|672655|这将会起作用：|672656|Map<Object,+Object>+map+=+new+HashMap<Object,+Object>();|672657|..。但这对你没什么用处。|672658|从根本上说，Properties永远不应该成为HashTable的子类……这就是问题所在。自从v1以来，它总是能够存储非字符串键和值，尽管这有悖于它的意图。如果使用组合，API只能使用字符串键/值，一切都会很好。|672659|你可能想要这样的东西：|672660|Map<String,+String>+map+=+new+HashMap<String,+String>();
for+(String+key+:+properties.stringPropertyNames())+{
++++map.put(key,+properties.getProperty(key));
}|672661|entityMap^0|0|A|E|J|11|J|0|0|0|5|1|7|1|A|6|0|2|J|N|13|0|0|0|0|6|A|N|9|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@$9|15|A|16|B|C]|$9|17|A|18|B|C]|$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1B|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|1C|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1D|8|@$9|1E|A|1F|B|C]|$9|1G|A|1H|B|C]|$9|1I|A|1J|B|C]]|D|@]|E|$]]|$1|O|3|P|5|6|7|1K|8|@$9|1L|A|1M|B|C]|$9|1N|A|1O|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1P|8|@]|D|@]|E|$]]|$1|S|3|T|5|J|7|1Q|8|@]|D|@]|E|$K|L]]|$1|U|3|V|5|6|7|1R|8|@]|D|@]|E|$]]|$1|W|3|X|5|6|7|1S|8|@$9|1T|A|1U|B|C]|$9|1V|A|1W|B|C]]|D|@]|E|$]]|$1|Y|3|Z|5|6|7|1X|8|@]|D|@]|E|$]]|$1|10|3|11|5|J|7|1Y|8|@]|D|@]|E|$K|L]]|$1|12|3|-4|5|6|7|1Z|8|@]|D|@]|E|$]]]|13|$]]

<code>Properties</code> implements <code>Map&lt;Object, Object&gt;</code> - not <code>Map&lt;String, String&gt;</code>.

You're trying to call this constructor:

<pre><code>public HashMap(Map&lt;? extends K,? extends V&gt; m)
</code></pre>

... with <code>K</code> and <code>V</code> both as <code>String</code>.

But <code>Map&lt;Object, Object&gt;</code> isn't a <code>Map&lt;? extends String, ? extends String&gt;</code>... it can contain non-string keys and values.

This would work:

<pre><code>Map&lt;Object, Object&gt; map = new HashMap&lt;Object, Object&gt;();
</code></pre>

... but it wouldn't be as useful to you.

Fundamentally, <code>Properties</code> should never have been made a subclass of <code>HashTable</code>... that's the problem. Since v1, it's always been able to store non-String keys and values, despite that being against the intention. If composition had been used instead, the API could have only worked with string keys/values, and all would have been well.

You may want something like this:

<pre><code>Map&lt;String, String&gt; map = new HashMap&lt;String, String&gt;();
for (String key : properties.stringPropertyNames()) {
 map.put(key, properties.getProperty(key));
}
</code></pre>

blocks|key|1812741|text|如果您知道您的Properties对象只包含<String,+String>条目，则可以使用原始类型：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1812742|Properties+properties+=+new+Properties();
Map<String,+String>+map+=+new+HashMap<String,+String>((Map)+properties);|code-block|syntax|javascript|1812743|entityMap^0|7|A|M|G|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

If you know that your <code>Properties</code> object only contains <code>&lt;String, String&gt;</code> entries, you can resort to a raw type:

<pre><code>Properties properties = new Properties();
Map&lt;String, String&gt; map = new HashMap&lt;String, String&gt;((Map) properties);
</code></pre>

blocks|key|1812773|text|问题是Properties实现了Map<Object,+Object>，而HashMap构造函数需要一个Map<?+extends+String,+?+extends+String>。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1812774|This+answer解释了这个(相当违反直觉的)决定。简而言之:在Java5之前，Properties实现了Map+(因为当时还没有泛型)。这意味着您可以将任何Object放入Properties对象中。This+is+still+in+the+documenation:|1812775|1812776|因为Properties继承自Hashtable，所以put和putAll方法可以应用于Properties对象。强烈反对使用它们，因为它们允许调用者插入键或值不是Strings的条目。应该改用setProperty方法。|blockquote|1812777|1812778|1812779|为了保持兼容性，设计者别无选择，只能让它继承Java5中的Map<Object,+Object>。这是努力完全向后兼容的不幸结果，这使得新代码变得不必要地令人费解。|1812780|如果您只在Properties对象中使用字符串属性，那么您应该能够在构造函数中使用未经检查的强制转换：|1812781|Map<String,+String>+map+=+new+HashMap<String,+String>(+(Map<String,+String>)+properties);|code-block|syntax|javascript|1812782|或不带任何副本：|1812783|Map<String,+String>+map+=+(Map<String,+String>)+properties;|1812784|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/873691/1321716|1|http://docs.oracle.com/javase/7/docs/api/java/util/Properties.html^0|3|A|G|J|11|7|1G|13|0|16|A|1J|3|29|6|2H|A|0|B|0|2V|Y|1|0|0|2|A|F|9|R|3|V|6|18|A|2A|6|2P|B|0|0|0|T|J|0|5|A|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1A|8|@$9|1B|A|1C|B|C]|$9|1D|A|1E|B|C]|$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1J|8|@$9|1K|A|1L|B|C]|$9|1M|A|1N|B|C]|$9|1O|A|1P|B|C]|$9|1Q|A|1R|B|C]]|D|@$9|1S|A|1T|1|1U]|$9|1V|A|1W|1|1X]]|E|$]]|$1|H|3|-4|5|6|7|1Y|8|@]|D|@]|E|$]]|$1|I|3|J|5|K|7|1Z|8|@$9|20|A|21|B|C]|$9|22|A|23|B|C]|$9|24|A|25|B|C]|$9|26|A|27|B|C]|$9|28|A|29|B|C]|$9|2A|A|2B|B|C]|$9|2C|A|2D|B|C]]|D|@]|E|$]]|$1|L|3|-4|5|6|7|2E|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|2F|8|@]|D|@]|E|$]]|$1|N|3|O|5|6|7|2G|8|@$9|2H|A|2I|B|C]]|D|@]|E|$]]|$1|P|3|Q|5|6|7|2J|8|@$9|2K|A|2L|B|C]]|D|@]|E|$]]|$1|R|3|S|5|T|7|2M|8|@]|D|@]|E|$U|V]]|$1|W|3|X|5|6|7|2N|8|@]|D|@]|E|$]]|$1|Y|3|Z|5|T|7|2O|8|@]|D|@]|E|$U|V]]|$1|10|3|-4|5|6|7|2P|8|@]|D|@]|E|$]]]|11|$12|$5|13|14|15|E|$16|17]]|18|$5|13|14|15|E|$16|19]]]]

The problem is that <code>Properties</code> implements <code>Map&lt;Object, Object&gt;</code>, whereas the <code>HashMap</code> constructor expects a <code>Map&lt;? extends String, ? extends String&gt;</code>.

<a href="https://stackoverflow.com/a/873691/1321716">This answer</a> explains this (quite counter-intuitive) decision. In short: before Java 5, <code>Properties</code> implemented <code>Map</code> (as there were no generics back then). This meant that you could put any <code>Object</code> in a <code>Properties</code> object. <a href="http://docs.oracle.com/javase/7/docs/api/java/util/Properties.html" rel="nofollow noreferrer">This is still in the documenation:</a>

<blockquote>
 Because <code>Properties</code> inherits from <code>Hashtable</code>, the <code>put</code> and <code>putAll</code> methods
 can be applied to a <code>Properties</code> object. Their use is strongly
 discouraged as they allow the caller to insert entries whose keys or
 values are not <code>String</code>s. The <code>setProperty</code> method should be used instead.
</blockquote>

To maintain compatibility with this, the designers had no other choice but to make it inherit <code>Map&lt;Object, Object&gt;</code> in Java 5. It's an unfortunate result of the strive for full backwards compatibility which makes new code unnecessarily convoluted.

If you only ever use string properties in your <code>Properties</code> object, you should be able to get away with an unchecked cast in your constructor:

<pre><code>Map&lt;String, String&gt; map = new HashMap&lt;String, String&gt;( (Map&lt;String, String&gt;) properties);
</code></pre>

or without any copies:

<pre><code>Map&lt;String, String&gt; map = (Map&lt;String, String&gt;) properties;
</code></pre>

blocks|key|1978155|text|这个怎么样？|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1978156|+++Map+properties+=+new+Properties();
+++Map<String,+String>+map+=+new+HashMap<String,+String>(properties);|code-block|syntax|javascript|1978157|将导致警告，但在没有迭代的情况下可以工作。|1978158|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

How about this?

<pre><code> Map properties = new Properties();
 Map&lt;String, String&gt; map = new HashMap&lt;String, String&gt;(properties);
</code></pre>

Will cause a warning, but works without iterations.

blocks|key|671020|text|这只是因为HashMap的构造函数需要映射泛型类型的参数，而属性实现映射。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|671021|这将会起作用，不过会有一个警告|671022|++++Properties+properties+=+new+Properties();
++++Map<String,+String>+map+=+new+HashMap(properties);|code-block|syntax|javascript|671023|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

this is only because the constructor of HashMap requires an arg of Map generic type and Properties implements Map. 

This will work, though with a warning

<pre><code> Properties properties = new Properties();
 Map&lt;String, String&gt; map = new HashMap(properties);
</code></pre>

blocks|key|4103135|text|要做到这一点，有效的方法是按如下方式转换为通用Map：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4103136|Properties+props+=+new+Properties();

Map<String,+String>+map+=+(Map)props;|code-block|syntax|javascript|4103137|这将把一个Map<Object,+Object>转换成一个原始的映射，这对于编译器来说是"ok“的(只是警告)。一旦我们有了一个原始的Map，它将转换为Map<String,+String>，它也将是"ok“(另一个警告)。您可以使用注记@SuppressWarnings({+"unchecked",+"rawtypes"+})忽略它们|offset|length|style|CODE|4103138|这是可行的，因为在JVM中，对象实际上没有泛型类型。泛型类型只是一个在编译时验证事物的技巧。|4103139|如果某个键或值不是字符串，则会产生ClassCastException错误。在当前的Properties实现中，只要不使用Properties的超级Hashtable<Object,Object>中的可变调用方法，这种情况就不太可能发生。|4103140|所以，如果你不想用你的Properties实例做一些讨厌的事情，这就是你要做的。|4103141|entityMap^0|0|0|5|J|1V|3|24|J|3B|1A|0|0|H|I|16|A|1P|A|22|O|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@$I|X|J|Y|K|L]|$I|Z|J|10|K|L]|$I|11|J|12|K|L]|$I|13|J|14|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|15|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|16|8|@$I|17|J|18|K|L]|$I|19|J|1A|K|L]|$I|1B|J|1C|K|L]|$I|1D|J|1E|K|L]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1F|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]]|T|$]]

The efficient way to do that is just to cast to a generic Map as follows:

<pre><code>Properties props = new Properties();

Map&lt;String, String&gt; map = (Map)props;
</code></pre>

This will convert a <code>Map&lt;Object, Object&gt;</code> to a raw Map, which is "ok" for the compiler (only warning). Once we have a raw <code>Map</code> it will cast to <code>Map&lt;String, String&gt;</code> which it also will be "ok" (another warning). You can ignore them with annotation <code>@SuppressWarnings({ "unchecked", "rawtypes" })</code>

This will work because in the JVM the object doesn't really have a generic type. Generic types are just a trick that verifies things at compile time.

If some key or value is not a String it will produce a <code>ClassCastException</code> error. With current <code>Properties</code> implementation this is very unlikely to happen, as long as you don't use the mutable call methods from the super <code>Hashtable&lt;Object,Object&gt;</code> of <code>Properties</code>.

So, if don't do nasty things with your Properties instance this is the way to go.

blocks|key|1814802|text|你可以使用Google+Guava的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1814803|com.google.common.collect.Maps.fromProperties(Properties)|offset|length|1814804|entityMap|0|LINK|mutability|MUTABLE|url|https://google.github.io/guava/releases/19.0/api/docs/com/google/common/collect/Maps.html#fromProperties(java.util.Properties)^0|0|0|1L|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

You could use Google Guava's:

<a href="https://google.github.io/guava/releases/19.0/api/docs/com/google/common/collect/Maps.html#fromProperties(java.util.Properties)" rel="noreferrer">com.google.common.collect.Maps.fromProperties(Properties)</a>

blocks|key|1978313|text|Java+8的方式：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1978314|properties.entrySet().stream().collect(
++++Collectors.toMap(
+++++++++e+->+e.getKey().toString(),
+++++++++e+->+e.getValue().toString()
++++)
);|code-block|syntax|javascript|1978315|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The Java 8 way:

<pre><code>properties.entrySet().stream().collect(
 Collectors.toMap(
 e -&gt; e.getKey().toString(),
 e -&gt; e.getValue().toString()
 )
);
</code></pre>

blocks|key|1814832|text|我将使用以下Guava+API：com.google.common.collect.Maps#fromProperties|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1814833|Properties+properties+=+new+Properties();
Map<String,+String>+map+=+Maps.fromProperties(properties);|code-block|syntax|javascript|1814834|entityMap|0|LINK|mutability|MUTABLE|url|https://google.github.io/guava/releases/snapshot/api/docs/com/google/common/collect/Maps.html#fromProperties(java.util.Properties)^0|G|19|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

I would use following Guava API:
<a href="https://google.github.io/guava/releases/snapshot/api/docs/com/google/common/collect/Maps.html#fromProperties(java.util.Properties)" rel="noreferrer">com.google.common.collect.Maps#fromProperties</a>

<pre><code>Properties properties = new Properties();
Map&lt;String, String&gt; map = Maps.fromProperties(properties);
</code></pre>

blocks|key|1812887|text|我使用的是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1812888|for+(Map.Entry<Object,+Object>+entry:properties.entrySet())+{
++++map.put((String)+entry.getKey(),+(String)+entry.getValue());
}|code-block|syntax|javascript|1812889|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

i use this: 

<pre><code>for (Map.Entry&lt;Object, Object&gt; entry:properties.entrySet()) {
 map.put((String) entry.getKey(), (String) entry.getValue());
}
</code></pre>

blocks|key|1814836|text|您可以使用以下命令：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1814837|Map<String,+String>+map+=+new+HashMap<>();

props.forEach((key,+value)+->+map.put(key.toString(),+value.toString()));|code-block|syntax|javascript|1814838|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can use this:

<pre><code>Map&lt;String, String&gt; map = new HashMap&lt;&gt;();

props.forEach((key, value) -&gt; map.put(key.toString(), value.toString()));
</code></pre>

blocks|key|671097|text|当我看到Spring框架源代码时，我发现是这样的|type|unstyled|depth|inlineStyleRanges|entityRanges|data|671098|Properties+props+=+getPropertiesFromSomeWhere();
+//+change+properties+to+map
Map<String,String>+map+=+new+HashMap(props)|code-block|syntax|javascript|671099|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

When I see Spring framework source code,I find this way
<pre class="lang-java prettyprint-override"><code>Properties props = getPropertiesFromSomeWhere();
 // change properties to map
Map&lt;String,String&gt; map = new HashMap(props)
</code></pre>

<pre><code>Properties properties = new Properties();
Map&lt;String, String&gt; map = new HashMap&lt;String, String&gt;(properties);// why wrong?
</code></pre>

<a href="https://docs.oracle.com/javase/9/docs/api/java/util/Properties.html" rel="noreferrer"><code>java.util.Properties</code></a> is a implementation of <a href="https://docs.oracle.com/javase/9/docs/api/java/util/Map.html" rel="noreferrer"><code>java.util.Map</code></a>, And <a href="https://docs.oracle.com/javase/9/docs/api/java/util/HashMap.html#HashMap-java.util.Map-" rel="noreferrer"><code>java.util.HashMap</code>'s constructor</a> receives a <code>Map</code> type param. So, why must it be converted explicitly?

Converting java.util.Properties to HashMap<String,String>

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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Properties properties = new Properties();Map<String, String> map = new HashMap<String, String>(properties);// why wrong?是的实现，接收Map类型参数。那么，为什么一定要显式转换呢？

问将java.util.Properties转换为HashMap<String，String>
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