黑马18-1：泛型ArrayList<String>，TreeSet<Person> ts = new TreeSet<Person>(new Comparat

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package cn.itcast.p1.generic.demo;

import java.util.ArrayList;
import java.util.Iterator;

public class GenericDemo {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		
		int[] arr = new int[4];
//		arr[0] = 3.0;
		//如何将一个Integer类型转成String类型呢
		//首先设计编程就不合理，不能将Integer和String放到同一个容器中
		//也就是，在申明容器的时候，只能装同一种类型的元素，不同的类型就用不同的容器装
		
		ArrayList<String> al = new ArrayList<String>();
		
		al.add("abc");//public boolean add(Object obj)
		al.add("hahah");
//		al.add(4);//al.add(new Integer(4));
		
		Iterator<String> it = al.iterator();
		while(it.hasNext()){
			
			String str = it.next();
			System.out.println(str);
		}
	}

}

package cn.itcast.p1.generic.demo;

import java.util.Iterator;
import java.util.TreeSet;

import cn.itcast.p2.bean.Person;
import cn.itcast.p3.comparator.ComparatorByName;

public class GenericDemo2 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {

		TreeSet<Person> ts = new TreeSet<Person>(new ComparatorByName());
		ts.add(new Person("lisi8",21));
		ts.add(new Person("lisi3",23));
		ts.add(new Person("lisi",21));
		ts.add(new Person("lis0",20));
		
		Iterator<Person> it = ts.iterator();
		
		while(it.hasNext()){
			Person p = it.next();
			System.out.println(p.getName()+":"+p.getAge());
		}
	}

}

package cn.itcast.p2.bean;

public class Person implements Comparable<Person> {

	private String name;
	private int age;

	public Person() {
		super();
		
	}

	public Person(String name, int age) {
		super();
		this.name = name;
		this.age = age;
	}


	public int compareTo(Person p){
		
//		Person p = (Person)obj;
		int temp = this.age - p.age;
		return temp==0?this.name.compareTo(p.name):temp;
	}
	
	//！！！！用IDE快捷生成，重写hashCode对应本类属性的判断唯一性，将重复的对象去掉
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + age;
		result = prime * result + ((name == null) ? 0 : name.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Person other = (Person) obj;
		if (age != other.age)
			return false;
		if (name == null) {
			if (other.name != null)
				return false;
		} else if (!name.equals(other.name))
			return false;
		return true;
	}

	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}

	@Override
	public String toString() {
		
		return "Person1111:"+getName()+":"+getAge();
	}

package cn.itcast.p3.comparator;

import java.util.Comparator;

import cn.itcast.p2.bean.Person;

public class ComparatorByName implements Comparator<Person> {

	@Override
	public int compare(Person o1, Person o2) {
		
		int temp = o1.getName().compareTo(o2.getName());
		return temp==0? o1.getAge()-o2.getAge(): temp;
	}

}

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