java泛型编程

package com.genericity;import org.junit.Test;/*** @Title: LinkedListStack.java * @Package com.genericity * @Description: 编写一个泛型栈（链表式）* @author lky * @date 2015年10月17日 下午8:34:07 * @version V1.0 */public class LinkedListStack<T> {        /**    * @Title: LinkedListStack.java     * @Package com.genericity     * @Description:定义栈中的节点类型    * @author lky     * @date 2015年10月17日 下午8:38:51     * @version V1.0     */    PRivate static class Node<U>{        U item;        Node<U> next;                Node(){            this.item=null;            this.next=null;        }        Node(U item,Node<U>next){            this.item=item;            this.next=next;        }                boolean isEmpty(){            return item==null && next==null;        }            }        private Node<T> top=new Node<T>();//栈顶指针        public void push(T item){  //入栈        top=new Node<T>(item,top);    }        public T pop(){    //出栈        T result=top.item;        if(!top.isEmpty()){            top=top.next;        }        return result;    }        }

package com.genericity;import org.junit.Test;public class testLinkedListStack {    @Test    public void testPush(){        LinkedListStack<String> aLinkedListStack=new LinkedListStack<String>();        aLinkedListStack.push("lky");        aLinkedListStack.push("aaaa");        String res=aLinkedListStack.pop();        while(res!=null){            System.out.println(res);            res=aLinkedListStack.pop();        }    }}

package com.genericity;import java.util.ArrayList;import java.util.Date;import org.junit.Test;public class GenericMethods  {        /**    * @Title: getType     * @Description: 返回任意数组的数据类型    * @param item     */    public <T> String getType(T item){        return item.getClass().getName();    }        @Test    public void test(){        System.out.println(new GenericMethods().getType(new Date()));        System.out.println(new GenericMethods().getType(1));        System.out.println(new GenericMethods().getType("lky"));        System.out.println(new GenericMethods().getType(new ArrayList<String>()));    }}

package com.genericity;import java.util.ArrayList;import java.util.HashMap;import java.util.HashSet;import java.util.LinkedList;import java.util.List;import java.util.Map;import java.util.Queue;import java.util.Set;import org.junit.Test;public class New {    public <k, v> Map<k, v> map() {        return new HashMap<k, v>();    }    public <T> List<T> list() {        return new ArrayList<T>();    }    public <T> LinkedList<T> linkList() {        return new LinkedList<T>();    }    public <T> Set<T> set() {        return new HashSet<T>();    }    public <T> Queue<T> queue() {        return new LinkedList<T>();    }        @Test    public void test(){        New new1=new New();        Map<String, LinkedList<String>> lisMap=new1.map();    }}

package com.genericity;import java.util.HashSet;import java.util.Set;import org.junit.Test;public class Sets {        /**    * @Title: union     * @Description: 集合的并集    * @throws     */    public static <T> Set<T> union(Set<T> a,Set<T> b){        Set<T> set=new HashSet<T>(a);        set.addAll(b);        return set;    }        /**    * @Title: intersetion     * @Description: 集合交集     */    public static <T> Set<T> intersetion(Set<T>a,Set<T> b){        Set<T> set=new HashSet<T>(a);        set.retainAll(b);        return set;            }    /**    * @Title: difference     * @Description: 集合差集     */    public static <T> Set<T> difference(Set<T>a, Set<T> b){        Set<T> set=new HashSet<T>(a);        set.removeAll(b);        return set;    }        public static <T> Set<T> complement(Set<T>a,Set<T> b){       return  difference(union(a, b), intersetion(a, b));    }            @Test    public void test(){        HashSet<Integer> a=new HashSet<Integer>();        HashSet<Integer> b=new HashSet<Integer>();        for(int i=0;i<8;++i){            if(i<5)a.add(i);            if(i>2) b.add(i);         }                System.out.println(union(a, b).toString());        System.out.println(difference(a, b).toString());        System.out.println(intersetion(a, b).toString());        System.out.println(complement(a, b).toString());    }    }