Java Object-oriented generics

This first knowledge combing blog, I hope I can continue to summarize the knowledge.

This is the video you see in the Geek College, the catalogue is as follows, pretty clear. Then I'll remember what I said in the video.

Java object-oriented generics: Understanding Generics

A new feature of Java SE 1.5, the essence of generics is a parameterized type that can represent any data type.

Java object-oriented generics: using in constructors

Class gen<t>{

private T value;

No angle brackets are required for generics in Gen (T value) {//constructor

This.value=value;

}

public void SetValue (T t) {

this.value=t;

}

Public T GetValue () {

　　return this.value;

　　　　　　}

}

Public Class Demo () {

public static void Main (string[] args) {

gen<string> g = new gen<string> ("test");

Output G.getvalue ();

}

}

Java object-oriented generics: Specify multiple generics (typically two)

　　

Class gen<t,k>{

Private T take;

Private K key;

Gen (T take,k key) {///constructor does not need angle brackets for generics

This.take=take;

This.key=key;

}

... set get method

}

Public Class Demo () {

public static void Main (string[] args) {

gen<string,integer> g = new gen<string,integer> ();

G.settake ("test");

G.setkey (10);

}

}

Java object-oriented generics: wildcard characters

When you want to specify a generic type for a parameter in a method, use the "? "For example, because the parameter is info<t>

Java object-oriented generics: generic interface

Add <T> after interface name

Interface gen<t>{

public void say ();

}

1. Class Genimpl implements gen<string>{

　　Public Void Say () {

}

}

2.Class genimpl<t> implements gen<t>{

　　Public Void Say () {

}

}

Specifying the data type when using Genimpl specifically

Java object-oriented generics: generic methods

Public <T> T method name (T t)

Returns the type of the T type assigned to the call, int i = tell (10);

Java object-oriented generics: generic arrays

public static <t>void Tell (T arr[]) {

for (int i=0;i<arr.length;i++) {

System.out.print (Arr[i])

}

}

Integer arr[]={1,2,3,4};

Tell (ARR);

http://blog.csdn.net/flfna/article/details/6576394

Java Object-oriented generics