Java 8 new Features-4 method references

For reference , we are generally used in objects, and object reference is characterized by: different reference objects can manipulate the same piece of content !

The method reference for Java 8 defines four formats:

• • reference static method span>     classname   :: staticmethodname 
  • reference object Method :  object:: 
  • reference specific type method : classname :: methodname 
  • construction method : classname  :: New

• static method Reference Example

  • /*** Static method reference *@param<P> parameter types for reference methods *@param<R> return type of a reference method*/@FunctionalInterfaceInterfaceFunstaticref<p,r>{     PublicR trantest (P p);} Public Static voidMain (string[] args) {/** Static method reference: public static string ValueOf * The string's ValueOf () method is referred to as the Funstaticref#trantest method */Funstaticref<integer, string> funstaticref =string::valueof; String Str= Funstaticref.trantest (10000); System.out.println (Str.replaceall ("0", "9"));}

• Object MethodsReference Example

  • /*** Common Method Reference *@param<R> Reference method return type*/@FunctionalInterfaceInterfaceInstanref<r>{     PublicR uppercase ();} Public Static voidMain (string[] args) {/** Reference to normal method: public String touppercase () **/String str2= "I See You"; Instanref<String> Instanref =str2:: touppercase; System.out.println (Instanref.uppercase ());}

• Example of a specific type method reference
  • 　　A reference to a particular method is difficult to understand, and itself refers to a common method, but the way it is quoted is: ClassName:: MethodName
  • 　　

    /*** References to specific methods *@param<P>*/@FunctionalInterfaceInterfaceSpecificmethodref<p>{     Public intCompare (P P1, p p2);} Public Static voidMain (string[] args) {/** Reference to a specific method public int compareTo (String anotherstring) * Compared to previous methods, the method reference no longer needs to define the object, but can be understood to define the object on the parameter! */Specificmethodref<String> Specificmethodref =String:: compareTo; System.out.println (Specificmethodref.compare ("A", "B")); Constructorref<Book> constructorref = Book::New; Book Book= Constructorref.createobject ("Java", 100.25); SYSTEM.OUT.PRINTLN (book);}

• Constructor Method Reference Example
  • 　　

    classbook{PrivateString title; Private DoublePrice ;  PublicBook () {} PublicBook (String title,DoublePrice ) {         This. Price =Price ;  This. title =title; } @Override PublicString toString () {return"book{" + "title=" + title + ' \ ' + ", price=" + Price + '} '; }}
    
     Public Static voidMain (string[] args) {/** Construction Method Reference*/Constructorref<Book> constructorref = Book::New; Book Book= Constructorref.createobject ("Java", 100.25); SYSTEM.OUT.PRINTLN (book);}

In General, some of the new features of Java 8 have not been used extensively in the projects currently being done, but learning about it will not be enough to see the code for this new Java 8 feature without knowing what is wrong!

Java 8 new Features-4 method references