java SONAR：用方法引用替换这个 lambda
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SONAR: Replace this lambda with a method reference
提问by Chris311
Sonar tells me "Replace this lambda with a method reference"
声纳告诉我“用方法引用替换这个 lambda”
public class MyClass {
private List<SomeValue> createSomeValues(List<Anything> anyList) {
return anyList //
.stream() //
.map(anything -> createSomeValue(anything)) //
.collect(Collectors.toList());
}
private SomeValue createSomeValue(Anything anything) {
StatusId statusId = statusId.fromId(anything.getStatus().getStatusId());
return new SomeValue(anything.getExternId(), statusId);
}
}
Is this possible here? I tried several things, like
这可能吗？我尝试了几件事，比如
.map(MyClass::createSomeValue) //
but I need to change the method to static then. And I am not a big fan of static methods.
但我需要将方法更改为静态。而且我不是静态方法的忠实粉丝。
Explanation of SonarQube is:
SonarQube 的解释是：
Method/constructor references are more compact and readable than using lambdas, and are therefore preferred.
方法/构造函数引用比使用 lambda 更紧凑和可读，因此是首选。
回答by Tunaki
Yes, you can use this::createSomeValue:
是的，您可以使用this::createSomeValue：
private List<SomeValue> createSomeValues(List<Anything> anyList) {
return anyList //
.stream() //
.map(this::createSomeValue) //
.collect(Collectors.toList());
}
This kind of method referenceis called "Reference to an instance method of a particular object". In this case, you are referring to the method createSomeValueof the instance this.
这种方法引用称为“对特定对象的实例方法的引用”。在这种情况下，您指createSomeValue的是实例的方法this。
Whether it is "better" or not that using a lambda expression is a matter of opinion. However, you can refer to this answerwritten by Brian Goetzthat explains why method-references were added in the language in the first place.
使用 lambda 表达式是否“更好”是一个见仁见智的问题。但是，您可以参考Brian Goetz写的这个答案，它解释了为什么首先在语言中添加了方法引用。
