使用继承：

Parent.java

public abstract class Parent<T> {    public abstract void display(T t);}

ChildString.java

public class ChildString extends Parent<String> {    @Override    public void display(String t) {        // Do something here...    }}

ChildInteger.java

public class ChildInteger extends Parent<Integer> {    @Override    public void display(Integer t) {        // Do something here...    }}

ChildDouble.java

public class ChildDouble extends Parent<Double> {    @Override    public void display(Double t) {        // Do something here...    }}

并访问子类，而不是直接访问父类。

更新资料

这里再举一个例子：

GenericType.java

public class GenericType {    public void display(Object t) {        String msg;        if(t instanceof String) { msg = "String";        } else if (t instanceof Integer) { msg = "Integer";        } else if (t instanceof Double) { msg = "Double";        } else { msg = "Another Object";        }        System.out.println(msg);    }}

SpecificGeneric.java

public class SpecificGeneric {    public static void main(String[] args) {        GenericType basicType = new GenericType();        basicType.display(new String());        basicType.display(new Integer(1));        basicType.display(new Double(0.1));    }}