Question

JAVA 泛型类中再定义已存在的一个泛型类 代码如下，怎么把GenericInGeneric类的结果输出，像GenericDesign

类一样，执行方法setFoo()和getFoo()后输出结果
public class GenericDesign <T> {
private T foo;

public void setFoo(T foo ){
this.foo=foo;
}

public T getFoo(){
return foo;
}
}
---------------------------------------------------------
public class GenericInGeneric<T> {
private GenericDesign<T> foo;
public void setFoo(GenericDesign<T> foo){
this.foo=foo;
}

public GenericDesign<T> getFoo(){
return foo;
}

}
---------------------------------------------------------
public class GenericDemo2 {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub

GenericDesign<Integer> foo=new GenericDesign<Integer>();
foo.setFoo(new Integer(15));
Integer b3=foo.getFoo();
System.out.println(b3);

GenericInGeneric<Integer> inGeneric=new GenericInGeneric<Integer>();
inGeneric.setFoo(foo);
}
}
不是只要结果是要写出输出语句 输出GenericInGeneric类的结果

Answer 1

public class GenericDemo2 {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub

GenericDesign<Integer> foo=new GenericDesign<Integer>();
foo.setFoo(new Integer(15));
Integer b3=foo.getFoo();
System.out.println(b3);

GenericInGeneric<Integer> inGeneric=new GenericInGeneric<Integer>();
inGeneric.setFoo(foo);
System.out.println(inGeneric.getFoo().getFoo());//是要这一句么
}
}
如楼上所说,你的设计上面估计会有些问题

Answer 2

GenericInGeneric<Integer> inGeneric=new GenericInGeneric<Integer>();
你的GenericInGeneric类需要的一个GenericDesign的对象 你这么写感觉非常的怪
说去来GenericInGeneric<T> 这样根本就不需要 因为GenericDesign已经有了类似的功能

public class GenericInGeneric {
private GenericDesign<T> foo;
public void setFoo(GenericDesign<T> foo){
this.foo=foo;
}

public GenericDesign<T> getFoo(){
return foo;
}

}
这么写然后
GenericInGeneric inGeneric=new GenericInGeneric();
inGeneric.setFoo(foo);