Groovy Tip 1 = =, equals, and others

We say Java project development based on groovy language is an agile development, and the groovy language itself offers a lot of agility in addition to using grails as a Web development platform.

We know that in the Java language, we use the Equals method to determine whether the values of two strings are equal, and "= =" as symbols that determine whether two object references are the same. It turns out that we use the Equals method more than the "= =" notation, especially in the use of strings.

In the actual coding process, the shape is as follows:

if(abc1.equals(abc2))
　　{
　　　 ……
　　}

Such an If language is particularly numerous, but each time we have to spell the Equals method, instead of simply using the "= =" symbol. While Ides such as Eclipse can help us spell the Equals method, the use of the Equals method delays our time, far from using the "= =" Symbol for agility.

The groovy language takes into account our actual requirements and decisively uses the "= =" notation instead of the Equals method to provide the agility of groovy language programming.

def abc1 = 'abc'
　　def abc2 = "abc"
println abc1 == abc2

The result printed is true.

In this way, we do not have to abc1.equals the IF (ABC2), but can use directly:

if(abc1==abc2)
　　{
　　　 ……
　　}

Is it convenient for many?

You can even use the "= =" symbol to determine whether the contents of a collection two objects are the same, such as:

def list1 = [1]
　　def list2 = [1]
println list1 == list2

You can run the above statement to see that the result is true.

The contents of the two Map objects are the same or can be judged by the "= =" notation, such as:

def map1 = ['name':'tom']
　　def map2 = ['name':'tom']
println map1 == map2

The result is true. But you have to run the following statement:

def map1 = ['name':'tom']
　　def map3 = ['name':'alice']
println map1 == map3