tostring

Explicit vs implicit call of toString

由 纵饮孤独 提交于 2019-11-26 13:05:42
问题 I used to use the implicit call of toString when wanting some debug info about an object, because in case of the object is null it does not throw an Exception. For instance: System.out.println(\"obj: \"+obj); instead of: System.out.println(\"obj: \"+obj.toString()); Is there any difference apart from the null case? Can the latter case work, when the former does not? Edit: What exactly is done, in case of the implicit call? 回答1: There's little difference. Use the one that's shorter and works

1和new Number(1)有什么区别

由 萝らか妹 提交于 2019-11-26 12:46:02
1和new Number(1)有什么区别 author: @Tiffanysbear 总结，两者的区别就是原始类型和包装对象的区别。 什么是包装对象 对象Number、String、Boolean分别对应数字、字符串、布尔值，可以通过这三个对象把原始类型的值变成（包装成）对象: var v1 = new Number(123); var v2 = new String('abc'); var v3 = new Boolean(true); 我们来看下实际的v1、v2、v3是什么呢？ typeof v1;// "object" typeof v2;// "object" typeof v3;// "object" v1 === 123; // false v1 == 123; // true 可以理解的是，v1此时是对象，===比较的是内存地址，因此跟数字Number 123不相等；可是为什么v1 == 123得到的值会是true呢？ 那这就是包装对象在使用时的问题了。再来理解一下什么是原始类型。 什么是原始类型 比如123这类就是原始类型，原始类型并不是一个对象，因此并没有对象具有的一些属性和方法；但是为什么能调用(123).toFixed()这些方法呢？ 原因就是这些方法都是像包装对象"借用"来的，toFixed方法是在Number对象原型上的方法。 (123).toFixed

MyEclipse快速生成setter、getter、toString()、有参构造函数、无参构造函数

由 ♀尐吖头ヾ 提交于 2019-11-26 12:32:46
简单来说举一反三！！！ 首先将鼠标移动到属性，点击右键如下图所示： 找到Source然后点击generate getters and setters。(同理toString()、有参构造函数、无参构造函数点击Source中对应的选项即可) 选择select all。然后eclipse就自动生成效果图如下：(同理toString()、有参构造函数、无参构造函数) 认真看过此篇的小伙伴，如果对你有收获，请点击旁边的小手推荐一下，如果有误，欢迎指正，谢谢！ 版权声明：此篇为本人原创，转载请标明出处：https://www.cnblogs.com/YQian/p/11320289.html 我的博客园地址：https://www.cnblogs.com/YQian/ 来源： https://www.cnblogs.com/YQian/p/11320289.html

Double ToString - No Scientific Notation [duplicate]

由 こ雲淡風輕ζ 提交于 2019-11-26 11:29:03
问题 This question already has an answer here: Double to string conversion without scientific notation 17 answers I just came across the wonderful \"feature\" that .NET will by default do Double.ToString() using scientific notation if there are enough decimal places. .005.ToString() // \".005\" .00005.ToString() // \"5E-05\" Does anyone know an efficient way to get this to appear as a string in standard (non-scientific) notation? I\'ve seen this question, but the top two answers seem kind of hacky

Convert double to string C++? [duplicate]

由 那年仲夏 提交于 2019-11-26 09:26:08
问题 Possible Duplicate: How do I convert a double into a string in C++? I want to combine a string and a double and g++ is throwing this error: main.cpp: In function ‘int main()’: main.cpp:40: error: invalid operands of types ‘const char [2]’ and ‘double’ to binary ‘operator+’ Here is the line of code which it is throwing the error on: storedCorrect[count] = \"(\"+c1+\",\"+c2+\")\"; storedCorrect[] is a string array, and c1 and c2 are both doubles. Is there a way to convert c1 and c2 to strings

Reverse (parse the output) of Arrays.toString(int[]) [duplicate]

由 ℡╲_俬逩灬. 提交于 2019-11-26 08:33:32
问题 This question already has an answer here: Convert String to int array in java 9 answers Is there in the JDK or Jakarta Commons (or anywhere else) a method that can parse the output of Arrays.toString, at least for integer arrays? int[] i = fromString(Arrays.toString(new int[] { 1, 2, 3} ); 回答1: Pretty easy to just do it yourself: public class Test { public static void main(String args[]){ int[] i = fromString(Arrays.toString(new int[] { 1, 2, 3} )); } private static int[] fromString(String

Is it possible in Java to override 'toString' for an Objects array?

由 大兔子大兔子 提交于 2019-11-26 08:24:49
问题 Is it possible in Java to override a toString for an Objects array? For example, let\'s say I created a simple class, User (it doesn\'t really matter which class is it since this is a general question). Is it possible that, once the client creates a User[] array and the client uses System.out.print(array) , it won\'t print the array\'s address but instead a customized toString() ? PS: of course I can\'t just override toString() in my class since it\'s related to single instances. 回答1: No. Of

How do I automatically display all properties of a class and their values in a string? [duplicate]

由 六月ゝ 毕业季﹏ 提交于 2019-11-26 08:23:50
问题 This question already has an answer here: C#: Printing all properties of an object [duplicate] 9 answers Imagine a class with many public properties. For some reason, it is impossible to refactor this class into smaller subclasses. I\'d like to add a ToString override that returns something along the lines of: Property 1: Value of property 1\\n Property 2: Value of property 2\\n ... Is there a way to do this? 回答1: I think you can use a little reflection here. Take a look at Type.GetProperties

How to make JSON.Net serializer to call ToString() when serializing a particular type?

由 北战南征 提交于 2019-11-26 08:23:07
问题 I am using Newtonsoft.Json serializer to convert C# classes to JSON. For some classes I don\'t need the serializer to an instance to individual properties, but instead just call ToString on the object, i.e. public class Person { public string FirstName { get; set; } public string LastName { get; set; } public override string ToString() { return string.Format(\"{0} {1}\", FirstName, LastName ); } } What should I do to get the Person object serialized as the result of its ToString() method? I

Dumping a java object's properties

由 别来无恙 提交于 2019-11-26 07:55:56
问题 Is there a library that will recursively dump/print an objects properties? I\'m looking for something similar to the console.dir() function in Firebug. I\'m aware of the commons-lang ReflectionToStringBuilder but it does not recurse into an object. I.e., if I run the following: public class ToString { public static void main(String [] args) { System.out.println(ReflectionToStringBuilder.toString(new Outer(), ToStringStyle.MULTI_LINE_STYLE)); } private static class Outer { private int intValue
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