JAVA学习第三十九课（常用对象API）— Map集合及其子类对象（集合使用技巧）

import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
class Man
{
    private String name;
    private int age;
    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;
    }
    public Man(String name, int age) {
        super();
        this.name = name;
        this.age = age;
    }
    public Man() {
        super();
        // TODO Auto-generated constructor stub
    }
    @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 ||getClass() != obj.getClass() )
            return false;

        Man other = (Man) obj;
        if (age != other.age)
            return false; 
            /*   if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;*/
        if(name==null ? other.name !=null : !name.equals(other.name))
            return false;
        return true;
    }
}
public class JiaoYan
{
    public static void main(String[] args) {
        HashMapDemo();
    }
    public static void HashMapDemo(){
        //人和籍贯 通过键值对存储在HashMap中
        HashMap<Man, String> hm = new HashMap<Man,String>();
        hm.put(new Man("周",1),"上海");
        hm.put(new Man("周",1),"东北");//要保证哈希表，所以Man中的HashCode和equals方法要复写
        hm.put(new Man("王",4),"北京");
        hm.put(new Man("孙",2),"广州");
        hm.put(new Man("赵",6),"山东");

        Iterator<Man> it =  hm.keySet().iterator();
        while(it.hasNext()){
            Man man = it.next();
            String bir = hm.get(man);
            System.out.println("man - bir :"+man.getName()+","+man.getAge()+" - "+bir);
        }
    }
}

import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
class Man extends Object
{
private String name;
private int age;
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;
}
public Man(String name, int age) {
super();
this.name = name;
this.age = age;
}
public Man() {
super();
// TODO Auto-generated constructor stub
}
@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;
Man other = (Man) 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;
}
}
class Compararule implements Comparator<Object>
{
public int compare(Object arg0, Object arg1) {
if(!(arg0 instanceof Man))
throw new ClassCastException();

Man man = (Man)arg0;
Man man2 = (Man)arg1;
int te = man.getAge() - man2.getAge();
return te==0?man.getName().compareTo(man2.getName()):te;
}
}
public class Main
{
public static void main(String[] args) {
TreeMapDemo();
}
public static void TreeMapDemo(){
TreeMap<Man, String> tm = new TreeMap<Man,String>(new Compararule());
tm.put(new Man("zhou",1),"上海");
tm.put(new Man("zhou",1),"东北");//要保证哈希表，所以Man中的HashCode和equals方法要复写
tm.put(new Man("wang",4),"北京");
tm.put(new Man("sun",2),"广州");
tm.put(new Man("zhao",6),"山东");

Iterator<Map.Entry<Man,String>> it =  tm.entrySet().iterator();
while(it.hasNext()){
Map.Entry<Man, String> mEntry = it.next();
Man man = mEntry.getKey();
String bir = mEntry.getValue();
System.out.println("man - bir :"+man.getName()+","+man.getAge()+" - "+bir);
}
}
}