泛型 构造方法中使用
class Gener<T>{
private T value;
public T getValue() {
return value;
}
public void setValue(T value) {
this.value = value;
}
public String toString(){
return this.getValue().toString();
}
}
public class Demo01 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Gener<String> g = new Gener<String>();
g.setValue("Hello World");
say(g);
}
public static void say(Gener<?> g){
System.out.println(g.toString());
}
}
泛型 通配符的使用：
使用泛型时，如果事先不知道是什么类型，可以使用？通配符
class Gener<T>{
private T value;
public T getValue() {
return value;
}
public void setValue(T value) {
this.value = value;
}
public String toString(){
return this.getValue().toString();
}
}
public class Demo01 {
public static void main(String[] args) {
Gener<String> g = new Gener<String>();
g.setValue("Hello World");
say(g);
}
public static void say(Gener<?> g){
System.out.println(g.toString());
}
}
泛型接口：
interface Gener1<T> {
public void say();
}
class Gar<T> implements Gener1<T> {
private String value;
public Gar(String value) {
this.value = value;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
@Override
public void say() {
}
}
public class Demo02 {
public static void main(String[] args) {
// TODO Auto-generated method stub
Gar<String> g = new Gar<String>("Hello World");
System.out.println(g.getValue());
}
}
泛型方法：
泛型方法中可以定义泛型参数，此时，参数的类型就是传入数据类型
class Genera {
public <T> T say(T t) {
return t;
}
}
public class Demo03 {
public static void main(String[] args) {
Genera g = new Genera();
String result = g.say("Hello World");
int result1 = g.say(10);
System.out.println(result);
System.out.println(result1);
}
}
泛型数组：
public class Demo04 {
public static void main(String[] args) {
Integer arr[] = { 1, 2, 3, 4 };
d(arr);
String a[] = { "Hello", "World", "Gracy" };
d(a);
}
public static <T> void d(T arr[]) {
for (int i = 0; i < arr.length; i++) {
System.out.println(arr[i]);
}
}
}