容器类

package com.wlh.collection;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

public class TestList {

	public static void main(String[] args) {

		Collection c = new ArrayList();
		//可以放入不同类型的对象
		c.add("hello");
		c.add(new Name("f1", "l1"));
		c.add(new Name("f1", "l1"));
		c.add(11);//整型11将自动打包为对象new Integer(11);
		c.add(22);//整型12将自动打包为对象new Integer(11);
		
		//返回包含此 collection 中所有元素的数组
		Object [] obj=c.toArray();
		for(int i=0;i<obj.length;i++){
			System.out.println("obj"+i+":"+obj[i]);
		}
		
		
		Collection cc = new ArrayList();
		cc.add("hello");
		cc.add(11);
		cc.add("hello world");
		
		//contains方法：如果此 collection 包含指定的元素，则返回 true
		System.out.println(c.contains("hello"));//true
		
		//containsAll: 如果此collection 包含指定 collection 中的所有元素，则返回 true。
		System.out.println(c.containsAll(cc));//false
		
		//addAll: 将指定 collection 中的所有元素都添加到此 collection 中
		System.out.println(c.addAll(cc));
		
		
		
		//retainAll:交集,仅保留此 collection 中那些也包含在指定 collection 的元素（可选操作）。 
		//System.out.println(c.retainAll(cc));
		
		//removeAll:  移除此 collection 中那些也包含在指定 collection 中的所有元素（可选操作）。
		System.out.println(c.removeAll(cc));
		
		
		
		//ArrayList为什么有两个remove方法？
		//remove(int index) 是子类新添加的！
		//如果是父类引用指向子类对象，则找不到子类中新添加的方法。
		//要想调用子类新添加的方法，需要先转型
		//是优先自动打包呢？还是先去匹配方法？
		 c.remove("hello1");
		 System.out.print(c);
		 
		//要想调用子接口中新添加的方法，需要先转型
		 List a = (List) c;
		 a.remove(1);
		
		System.out.println(c.size());
		System.out.println(c);
		
		//clear:移除此 collection 中的所有元素(父接口Collection中的方法clear)
		c.clear();
		System.out.println(c);
	}

}

class Name {
	private String firstName, lastName;

	public Name(String firstName, String lastName) {
		this.firstName = firstName;
		this.lastName = lastName;
	}

	public String getFirstName() {
		return firstName;
	}

	public String getLastName() {
		return lastName;
	}

	//重写了tostring方法
	public String toString() {
		return firstName + "" + lastName;
	}
}



package com.wlh.collection;

//为什么调用两次c.add("hello");只加入一个hello?
//可见HashSet中是采用了比较元素hashCode的方法来判断元素是否相同（duplicate），
//而不是采用其他类似equals之类的东东来判断。

//一个对象被当作Map里面的key的时候,hashCode用来比较两个东东是不是相等
//hashCode非常适合用来做索引
//重写equals方法,通常需要重写hashCode方法.因为你的本意是想让他相等的.但hashCode如果不重写,不同的对象就不会相等
import java.util.*;

public class BasicContainer {
	
 public static void main( String[] args) {
    Collection c = new HashSet();
    c.add("hello");
    c.add("hello");
    c.add(new Name3("f1","l1"));
    c.add(new Name3("f1","l1"));
    
    System.out.println(new String("f1").hashCode()==new String("f1").hashCode());
    
    c.add(new Integer(100));
    c.remove("hello"); 
    c.remove(new Integer(100));
    System.out.println(c.remove(new Name3("f1","l1")));
    //System.out.println(c);
    System.out.println(new Name3("f1","l1").hashCode());
    System.out.println(new Name3("f1","l1").hashCode());
    System.out.println(c);

			List list = new ArrayList();
			list.add(new Name3("f2", "l2"));
			list.add(new Name3("f1", "l1"));
			list.add(new Name3("f5", "l5"));
			list.add(new Name3("f3", "l3"));
			Collections.sort(list);
			System.out.println(list);
}


}

class Name3 implements Comparable 
{

public String firstName,lastName;

public Name3(String firstName, String lastName) {
	this.firstName = firstName; 
	this.lastName = lastName;
}

public String getFirstName() {
	return firstName;
}
public String getLastName() {
	return lastName;
}

@Override
public String toString() {
	return firstName + " " + lastName;
}


@Override
public boolean equals(Object obj) {
    if (obj instanceof Name) {
        Name3 name = (Name3) obj;
        return (firstName.equals(name.firstName))
            && (lastName.equals(name.lastName));
    }
    return super.equals(obj);
}


@Override
public int hashCode() {
	System.out.println(firstName.hashCode());
   return firstName.hashCode();//这个对象当作为索引的时候会使用
}


public int compareTo(Object o) {
    Name3 n = (Name3)o;
    int lastCmp = 
        lastName.compareTo(n.lastName);
    return 
         (lastCmp!=0 ? lastCmp :
          firstName.compareTo(n.firstName));
}

	
}




package com.wlh.collection;

import java.util.Collection;
import java.util.HashSet;

public class TestSet {

	/**
	 * Set通过验证hashcode来判断2元素是否相等，先调用hashcode方法然后调用equals方法
	 */
	public static void main(String[] args) {
			    Collection c = new HashSet();
			    c.add("hello");
			    c.add("hello");
			    c.add(new Name4("f1","l1"));
			    c.add(new Name4("f1","l1"));
			    System.out.println(c);
	}
	
	
	
	
}
class Name4 //implements Comparable 
{

public String firstName,lastName;

public Name4(String firstName, String lastName) {
	this.firstName = firstName; 
	this.lastName = lastName;
}

public String getFirstName() {
	return firstName;
}
public String getLastName() {
	return lastName;
}

@Override
public String toString() {
	return firstName + " " + lastName;
}


@Override
public boolean equals(Object obj) {
    if (obj instanceof Name4) {
    	Name4 name = (Name4) obj;
    	System.out.println(firstName.equals(name.firstName));
        return (firstName.equals(name.firstName));
    }
    return super.equals(obj);
}


@Override
public int hashCode() {
	System.out.println(firstName.hashCode());
   return firstName.hashCode();//这个对象当作为索引的时候会使用
}


/*public int compareTo(Object o) {
	Name4 n = (Name4)o;
    int lastCmp = 
        lastName.compareTo(n.lastName);
    return 
         (lastCmp!=0 ? lastCmp :
          firstName.compareTo(n.firstName));
}*/

	
}



package com.wlh.collection;

import java.util.HashSet;
import java.util.Set;

public class SetTest5 { 
	  public static void main(String[] args){ 
	   Set set = new HashSet(); 
	   set.add(new SetElement5("aa")); 
	   set.add(new SetElement5("aa")); 
	   set.add(new SetElement5("bb")); 
	   System.out.println(set); 
	  } 
	  static class SetElement5{ 
	   String s; 
	   public SetElement5(String s){ 
	    this.s =  s; 
	   } 
	   public String toString(){ 
	    return s; 
	   } 
	   public boolean equals(Object obj) { 
		   System.out.println(s.equals(((SetElement5)obj).s));
	    return s.equals(((SetElement5)obj).s); 
	   } 
	   public int hashCode() { 
		   System.out.println(s.hashCode());
	    return s.hashCode(); 
	   } 
	  } 
	} 





package com.wlh.collection;

import java.util.Set; 
import java.util.*; 

/**
 * TreeSet中是采用Comparable接口中的compareTo方法来判断元素是否相同（duplicate），
 * 而不是采用其他类似equals之类的东东来判断。 
 * @author Administrator
 *
 */
public class TreeSetTest { 
	  public static void main(String[] args){ 
	   Set set = new TreeSet(); 
	   set.add(new SetElement2("aa")); 
	   set.add(new SetElement2("aa")); 
	   set.add(new SetElement2("bb")); 
	   System.out.println(set); 
	  } 
	  static class SetElement2 implements Comparable{ 
	   String s; 
	   public SetElement2(String s){ 
	    this.s =  s; 
	   } 
	   public String toString(){ 
	    return s; 
	   } 
	   public int compareTo(Object o){ 
	    return s.compareTo(((SetElement2)o).s); 
	   } 
	   public boolean equals(Object obj) { 
	    return s.equals(((SetElement2)obj).s); 
	   } 
	  } 
	} 


package com.wlh.collection;
import java.util.*;
class TestMap2 {
  public static void main(String args[]) {
    Map m1 = new HashMap(); 
    m1.put("one",new Integer(1));
    m1.put("one",new Integer(7));
    m1.put("two",new Integer(2));
    m1.put("three",new Integer(3));
    
    m1.put(new Name2("f1","l1"),"aaa");
    m1.put(new Name2("f1","l1"),"bbb");
    m1.put(new Name2("f1","l1"),"bbb");
    
    
    //m1.remove(new Name("f1","l1"));
    //System.out.println(m1);
    //System.out.println(m1.size());
    //System.out.println(m1.containsKey("one"));
    

    if(m1.containsKey("two")) {
      int i = ((Integer)m1.get("two")).intValue();
      //System.out.println(i);
    }

    Map m2 = new TreeMap();
	//m2.put("B","aaa");
	m2.put(new Name2("f1","l1"),"aaa");
	m2.put(new Name2("f1","l1"),"aaa");
    System.out.println(m2);
    //System.out.println(m2.containsValue("aaa"));
        
    
    
    Map m3 = new HashMap(m1);
    m3.putAll(m2);
    System.out.println(m3);
  }
}


class Name2 
implements Comparable 
{
	
	public String firstName,lastName;
    
	public Name2(String firstName, String lastName) {
		this.firstName = firstName; 
		this.lastName = lastName;
	}
    
	public String getFirstName() {
		return firstName;
	}
	public String getLastName() {
		return lastName;
	}

	@Override
    public String toString() {
		return firstName + " " + lastName;
	}
	
	
    @Override
    public boolean equals(Object obj) {
		System.out.println("equals.....");
	    if (obj instanceof Name) {
	        Name2 name = (Name2) obj;
	        return (firstName.equals(name.firstName))
	            && (lastName.equals(name.lastName));
	    }
	    return super.equals(obj);
	}
	
	
	@Override
	public int hashCode() {
		//System.out.println("==="+firstName.hashCode());
		System.out.println("hashCode.....");
	   return firstName.hashCode();//这个对象当作为索引的时候会使用
	}
	

	public int compareTo(Object o) {
		System.out.println("compareTo.....");
        Name2 n = (Name2)o;
        int lastCmp = lastName.compareTo(n.lastName);
        return 
             (lastCmp!=0 ? lastCmp : firstName.compareTo(n.firstName));
		
    }
	
		
}