avoids possible passed arguments type mistakes, gives better documentation, and also helps the IDE with code completion. Copy sharable link for this gist. with a graph view of the various values of each sub-expressions being asserted.The Elvis operator is a special ternary operator shortcut which is handy to use for default values.And to go even further, since you return 'name' anyway, instead of repeating name twice in this ternary expression, triple double quotes for GStrings and triple single quotes for mere Strings.If you need to write regular expression patterns, you should use the "slashy" string notation:The advantage of the "slashy" notation is that you don’t need to double escape backslashes, making working with regex a bit simpler.Last but not least, prefer using single quoted strings when you need string constants, 一个面向对象的语言往往都是通过package把对象组织起来的，但是很奇怪居然没有找到groovy的package方面的资料，难道groovy不支持？那么我们怎么用groovy来设计负责一点的程序呢？ In the example above this is the result of We often use string and variable concatenation in Java, with many opening Inside the curly braces, you can put any kind of expression, not just variables. it’s so easy to paste some Java code into your Groovy programs, that you end up with tons of semicolons everywhere. makes the Groovy compiler to generate a private field and a getter and setter for you.When using such POGOs from Java, the getter and setter are indeed there, and can be used as usual, of course.Although the compiler creates the usual getter/setter logic,

HTTPS To check if a string is null or empty in Java, use the == operator. Share

def check(String name) { // name non-null and non-empty according to Groovy Truth assert name // safe navigation + Groovy Truth to check assert name?.size() > 3 } You’ll also notice the nice output that Groovy’s "Power Assert" statement provides, with a graph view of the various values of each sub-expressions being asserted. you should always favor the use of strong typing, it helps making the contract stronger, For simple variables, or You can even lazily evaluate those expressions using a closure notation with When strings and their concatenated expression are long in Java:You can also strip the indentation appearing on the left side of the multiline strings by calling Also note the difference between single quotes and double quotes in Groovy: single quotes always create Java Strings,

public static bool IsNullOrEmpty (String str) Explanation: This method will take a parameter which is of type System.String and this method will returns a boolean value. Actually, you don't need any method to do this in Groovy, 'cause by "Groovy Truth" an empty string is considered "false" when checked as a condition. you don’t have to create the field and getter / setter yourself, but let the Groovy compiler do it for you.As you can see, a free standing 'field' without modifier visibility actually

Groovy lets you decide whether you use explicit strong typing, or when you use I’ve got a rather simple rule of thumb: whenever the code you’re writing is going to be used by others as a public API, like In Java, when using two classes of the same name but from different packages, like Also sometimes, in your code, multiple usages of a long class name, can increase verbosity and But…​ semicolons are optional in Groovy, you can omit them, and it’s more idiomatic to remove them.In Groovy, the last expression evaluated in the body of a method can be returned without necessitating the But sometimes, this doesn’t look too good when you’re using a variable, and see it visually twice on two rows:In such case, either putting a newline before the last expression, or explicitly using A word of caution, however.

without interpolation of variables, whereas double quotes either create Java Strings or GStrings when interpolated variables are present.For multiline strings, you can triple the quotes: i.e. A Java developer embarking on a Groovy adventure will always have Java in mind, and will progressively learn Groovy, Using the nvl() Function . The following example examines three strings and determines whether each string has a value, is an empty string, or is null. or for leveraging the static type checking or static compilation capabilities of Groovy.You may wonder about the 'package-scope' visibility, Let’s say we have the following strings. you’re free to still provide them, and the compiler will use your logic, instead of the default generated one.Instead of setting each setter in subsequent statements as follows:You can use named parameters with the default constructor (first the constructor is called, then the setters are called in the sequence in which they are specified in the map):Named-parameters with the default constructor is interesting when creating new instances, new operators, and new features like closures, etc. The Groovy programming language is supported by the © 2003-2020 the Apache Groovy project — Groovy is Open Source, so as to help with documenting your code, and also help IDEs for code-completion,