Error reason for converting string to long type: to convert to long type, it must be int, double, float type [easy to understand]

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The solution to this problem is one ：

String strTime = "12.5416132";
double dblTime = Double.parseDouble(strTime);
		
long lngTime = new Double(dblTime).longValue();
log.info("lngTime:"+lngTime);

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Please see the following examples and explanations for the specific reasons for the error report ：

The above example ：

string a =100.1;

long b=long.parse(a);

 Conversion times  “ The input string is not in the correct format ”

 When a =100.0  when 

long b=long.parse(a,NumberStyles.AllowDecimalPoint);

 It can be converted normally ,

 and  a=100.9  when 

long b=long.parse(a,NumberStyles.AllowDecimalPoint);

 switch views , Report exceeding Int64 Maximum or minimum of ,

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Explanation of the reason ：

 Question 1 ：long It's plastic surgery, that is Int64 type ,parse The object of must be an integer 

 Question two ：

 When a =100.0  when 

long b=long.parse(a,NumberStyles.AllowDecimalPoint);

 This is because of the use of NumberStyles.AllowDecimalPoint

 Indicates that the numeric string can have a decimal point .  If  NumberStyles  Values include  AllowCurrencySymbol  sign , The analyzed string includes currency symbols , Then the decimal separator character is composed of  NumberFormatInfo. CurrencyDecimalSeparator  Attribute determination . otherwise , The decimal separator is composed of  NumberFormatInfo. NumberDecimalSeparator  Attribute to determine .

 Actually, decimal points are allowed , But as a long, Still can't parse Non integer , At this time a yes 100.00, You can discard the decimal point as an integer . in other words long stay parse By default a Treat as 100 Come on parse Of .

 Question 3 ：

 At this time a become 100.1, The same is used NumberStyles.AllowDecimalPoint, But this time long the parse Is no longer an integer , So it will raise exceptions , exceed int64 That is to say long The scope of the , For this mistake , You can put it first. a=100.1 Make a transformation into shaping , Or more widely used double or decimal Come on parse, Such as decimal.Parse("100.1", NumberStyles.AllowDecimalPoint)

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