bigdecimal

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Spring Data MongoDB mapping by default converts BigDecimal to String. However, I want them to be converted as Double in mongodb. This is required for latter to make queries on this field in mongodb (comparison queries/aggregation queries). How can I reigster my own converter (BigDecimalToDouble / DoubleToBigDecimal) to do this? 回答1: Here's how you can add your own converters: <bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate"> <constructor-arg ref="mongoDbFactory"/> <constructor-arg ref="mappingConverter"/>

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: This question already has an answer here: BigDecimal from Double incorrect value? 3 answers Convert double to BigDecimal and set BigDecimal Precision 8 answers When BigDecimal is used with an input of double and BigDecimal with an input of String different results seem to appear. BigDecimal a = new BigDecimal(0.333333333); BigDecimal b = new BigDecimal(0.666666666); BigDecimal c = new BigDecimal("0.333333333"); BigDecimal d = new BigDecimal("0.666666666"); BigDecimal x = a.multiply(b); BigDecimal y = c.multiply(d); System.out.println(x);

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have a method that takes n and returns nth Fibonacci number. Inside the method implementation I use BigDecimal to get the nth Fibonacci number then I use method toBigInteger() to get the number as a BigInteger object and that's surely because I am working with huge numbers in my application. I keep getting correct results until I pass 1475 as an argument for my method. I get NumberFormatException: Infinite or NaN in this case without any clear reason for me. Could you please explain me why am I getting this exception? Here's my method:

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I am currently using the BigDecimal and it is giving me more decimals but not nearly enough for what I am trying to do. I need to be able to get all the way to the 10^6 digit. This is my current code BigDecimal num = new BigDecimal(103993/33102.0); pw.println(num.toString()); and it outputs 3.14159265301190249175533608649857342243194580078125 where the number actually has a lot more decimals: http://www.wolframalpha.com/input/?i=103993%2F33102 回答1: You are loosing the precision when evaluating this: 103993/33102.0 as a double division.

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have a BigDecimal variable BigDecimal x = new BigDecimal("5521.0000000001"); Formula: x = x.add(new BigDecimal("-1") .multiply(x.divideToIntegralValue(new BigDecimal("1.0")))); I want to remove the integer part, to get the value x = ("0.0000000001") , but my new value is 1E-10 and not the 0.0000000001. 回答1: To get a String representation of the BigDecimal without the exponent part, you can use BigDecimal.toPlainString() . In your example: BigDecimal x = new BigDecimal("5521.0000000001"); x = x.add(new BigDecimal("-1"). multiply(x

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have Hibernate method which returns me a BigDecimal. I have another API method to which I need to pass that number but it accepts Integer as parameter. I cannot change return types or variable types of both methods. Now how to convert the BigDecimal into Integer and pass it to second method? Is there a way out of this? 回答1: You would call myBigDecimal.intValueExact() (or just intValue() ) and it will even throw an exception if you would lose information. That returns an int but autoboxing takes care of that. 回答2: Can you guarantee that the

策略模式和工厂模式的搭配使用可以很好地消除代码 if-else 的多层嵌套 需求 针对店下商铺，有这样一个需求，对用户客户分为了普通客户、 vip 客户、超级 vip 用户、专属 vip 用户 4 个等级，每当用户购买商品时，针对不同的用户等级和消费金额采取不同的打折优惠策略。在平常的开发当中，必然会出现多层的 if-else 嵌套判断，先判断用户的等级再判断用户购买商品的消费金额。 弊端 以上的情况出现了多层的 if-else 嵌套，除此之外，以后如果需求再有变动，需要再增加一个用户等级，那么又会再次添加 if-else 的嵌套判断，那么如何解决上述的弊端呢，采用策略模式和工厂模式的搭配使用，可以很好地优化多层 if-else 的多层嵌套 实现 编写用户等级枚举类 java">package com.zbiti.ifelse.UserType; /** * 用户类型枚举类 */ public enum UserPayServiceEnum { VIP(1,"Vip"), SUPERVIP(2,"SuperVip"), PARTICULALYVIP(3,"ParticularlyVip"), NORMAL(4,"NormalPayService"); /** * 状态值 */ private int code; /** * 类型描述 */ private String value;

策略模式和工厂模式的搭配使用可以很好地消除代码 if-else 的多层嵌套 需求 针对店下商铺，有这样一个需求，对用户客户分为了普通客户、 vip 客户、超级 vip 用户、专属 vip 用户 4 个等级，每当用户购买商品时，针对不同的用户等级和消费金额采取不同的打折优惠策略。在平常的开发当中，必然会出现多层的 if-else 嵌套判断，先判断用户的等级再判断用户购买商品的消费金额。 弊端 以上的情况出现了多层的 if-else 嵌套，除此之外，以后如果需求再有变动，需要再增加一个用户等级，那么又会再次添加 if-else 的嵌套判断，那么如何解决上述的弊端呢，采用策略模式和工厂模式的搭配使用，可以很好地优化多层 if-else 的多层嵌套 实现 编写用户等级枚举类 package com.zbiti.ifelse.UserType; /** * 用户类型枚举类 */ public enum UserPayServiceEnum { VIP(1,"Vip"), SUPERVIP(2,"SuperVip"), PARTICULALYVIP(3,"ParticularlyVip"), NORMAL(4,"NormalPayService"); /** * 状态值 */ private int code; /** * 类型描述 */ private String value;