blocks|key|572484|text|parseDouble()的文档说“返回一个初始化为指定字符串所表示的值的新双精度值，正如double类的valueOf方法所执行的那样。”，因此它们应该是相同的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|572485|entityMap^0|0|D|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

Documentation for <code>parseDouble()</code> says "Returns a new double initialized to the value represented by the specified String, as performed by the valueOf method of class Double.", so they should be identical.

blocks|key|356746|text|如果您想将字符串转换为双精度数据类型，那么大多数人选择parseDouble()方法。请参见示例代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|356747|String+str+=+"123.67";
double+d+=+parseDouble(str);|code-block|syntax|javascript|356748|您将获得双精度的值。请参阅tutorialData上的StringToDouble教程。|offset|length|356749|entityMap|0|LINK|mutability|MUTABLE|url|http://tutorialdata.com/example/Java-Data-Types/StringToDouble.html^0|0|0|D|C|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

If you want to convert string to double data type then most choose parseDouble() method.
See the example code:

<pre><code>String str = "123.67";
double d = parseDouble(str);
</code></pre>

You will get the value in double. See the StringToDouble tutorial at <a href="http://tutorialdata.com/example/Java-Data-Types/StringToDouble.html" rel="nofollow">tutorialData</a>.

blocks|key|572579|text|它们都将字符串转换为double值，但是parseDouble()方法返回原始double值时，valueOf()方法进一步将原始double转换为包含原始Double值的double包装器类对象。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|572580|如果字符串中的值不能转换为双精度原语，则从字符串到双精度原语的转换可能会抛出NFE(NumberFormatException)。|572581|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

They both convert a String to a double value but wherease the parseDouble() method returns the primitive double value, the valueOf() method further converts the primitive double to a Double wrapper class object which contains the primitive double value. 

The conversion from String to primitive double may throw NFE(NumberFormatException) if the value in String is not convertible into a primitive double.

blocks|key|572651|text|parseDouble()方法用于初始化字符串(应该包含一些数值)，它返回的浮点值是原始数据类型，如....the、....the等。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|572652|但是valueOf()创建了一个包装器类的对象。你必须解开它才能得到双精度的值。它可以比作巧克力。制造商用锡纸或纸把巧克力包起来以防污染。用户拿起巧克力，取出并扔掉包装纸，然后吃掉它。|572653|观察以下转换。|572654|int+k+=+100;+Integer+it1+=+new+Integer(k);|offset|length|style|CODE|572655|使用Integer类将int数据类型k转换为对象it1。在需要k作为对象的任何地方，都可以在Java编程中使用it1对象。|572656|下面的代码可以用来解开(从Integer对象取回int+)对象it1。|572657|int+m+=+it1.intValue();|code-block|syntax|javascript|572658|System.out.println(m*m)；//打印10000|572659|//intValue()是Integer类的方法，返回int数据类型。|572660|entityMap^0|0|0|0|0|16|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|12|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|13|8|@$H|14|I|15|J|K]]|9|@]|A|$]]|$1|L|3|M|5|6|7|16|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|17|8|@]|9|@]|A|$]]|$1|P|3|Q|5|R|7|18|8|@]|9|@]|A|$S|T]]|$1|U|3|V|5|6|7|19|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|Z|$]]

parseDouble() method is used to initialise a STRING (which should contains some numerical value)....the value it returns is of primitive data type, like int, float, etc.

But valueOf() creates an object of Wrapper class. You have to unwrap it in order to get the double value. It can be compared with a chocolate. The manufacturer wraps the chocolate with some foil or paper to prevent from pollution. The user takes the chocolate, removes and throws the wrapper and eats it.

Observe the following conversion.

<code>int k = 100;
Integer it1 = new Integer(k);</code>

The int data type k is converted into an object, it1 using Integer class. The it1 object can be used in Java programming wherever k is required an object.

The following code can be used to unwrap (getting back int from Integer object) the object it1.

<pre><code>int m = it1.intValue();
</code></pre>

System.out.println(m*m); // prints 10000

//intValue() is a method of Integer class that returns an int data type.

I want to convert <code>String</code> to a <code>Double</code> data type. I do not know if I should use <code>parseDouble</code> or <code>valueOf</code>.

What is the difference between these two methods?

What is the difference between Double.parseDouble(String) and Double.valueOf(String)?

Java

我想将String转换为Double数据类型。我不知道应该使用parseDouble还是valueOf。这两种方法有什么不同？

问Double.parseDouble(字符串)和Double.valueOf(字符串)有什么区别？
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