ArrayList

package cn.zhuj.ArrayList1;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.ListIterator;

import cn.zhuj.util.ArrayListCapacity;
import cn.zhuj.util.outPut;

public class ArraylistTest {
	public static void main(String args[]) {
		// create a Dog Arraylist use the initialCapacity of 20
		ArrayList<Dog> arraylist = new ArrayList<Dog>();
		ArrayList<Dog> arraylist1 = new ArrayList<Dog>(5);
		
		arraylist.add(new Dog("pony", 45));
		arraylist.add(new Dog("lucy", 15));
		arraylist.add(new Dog("john", 25));
		arraylist.add(new Dog("mino", 35));
		arraylist.add(new Dog("tony", 45));
		arraylist.add(new Dog("JJ", 16));
		arraylist.add(new Dog("jackie", 55));
		arraylist.add(new Dog("nono", 18));
		arraylist.add(new Dog("JJ", 16));
		
		arraylist1.add(new Dog("jackie", 55));
		arraylist1.add(new Dog("bruce", 65));
		arraylist1.add(new Dog("tony", 25));
		arraylist1.add(new Dog("pony", 45));
		
		
		//add the element to the specified index of the ArrayList
		arraylist.add(1, new Dog("bruce", 65)); 
		

		
		//append all the elements of the specified ArrayList to the end of this ArrayList
//		arraylist.addAll(arraylist1);
		
		//append all the elements of the specified ArrayList to the specified index of this ArrayList
//		arraylist.addAll(2, arraylist1);
		
		//remove all the elements of the specified ArrayList
		//arraylist.clear();
		
		// if this ArrayList contains the specified element
		outPut.outPut("=======contains(Object o)=======",0);
		outPut.outPut("arraylist.contains = "+arraylist.contains(new Dog("JJ",16)),0);
		
		//if this ArrayList contains the specified ArrayList
		outPut.outPut("=======containsAll(Collection<? extends E> c)=======",0);
		outPut.outPut("arraylist.contrainsAll = "+arraylist.containsAll(arraylist1),0);
		
		//expand this ArrayList's capacity must over 1.5 times of the oldCapacity otherwise capacity will be 1.5*oldCapacity instead of the argument 
		arraylist.ensureCapacity(16);
		
		//java 1.8 new Lambda expression  like javaScript ES6
		outPut.outPut("=======forEach(Consumer<? super E>action)========",0);
		arraylist.forEach(e->outPut.outPut(e));
		
		//cout/syso the specified index element of this ArrayList
		outPut.outPut("\n=======get(int index)=======",0);
		outPut.outPut("index(1) = ",arraylist.get(1));;
		
		
		Dog d = new Dog("JJ",16);
		
		// the index of the first occurrence of the specified element of the ArrayList
		outPut.outPut("\n=======indexOf(Object o)=======",0);
		outPut.outPut("index = "+arraylist.indexOf(d),0);
		// the index of the last occurrence of the specified element of the ArrayList
		outPut.outPut("=======lastIndexOf(Object o)=======",0);
		outPut.outPut("lastIndex = "+arraylist.lastIndexOf(d),0);
		
		// return proper sequence called iterator
		outPut.outPut("=======iterator()=======",0);
		Iterator<Dog> it = arraylist.iterator();
		while(it.hasNext()) {
			Dog d2 = it.next();
			if(d2.getName() == "mino") {
				outPut.outPut("mino's age = "+d2.getAge(),0);
			}
		}
		//this ArrayList contains no element
		outPut.outPut("=======isEmpty()========",0);
		outPut.outPut("isEmpty = "+arraylist.isEmpty(),0);
		
		//use reflection to show the capacity of this ArrayList
		outPut.outPut("=======java.lang.reflect========",0);
		ArrayListCapacity.ArrayListCapacity(arraylist);
		// return proper sequence called listIterator
		outPut.outPut("=======ListIterator()========",0);
		ListIterator<Dog> lit = (ListIterator<Dog>) arraylist.listIterator();		
		while(lit.hasNext()) {
			Dog dog = lit.next();
			if(dog.getName() == "nono") {
				outPut.outPut("nono's age = "+dog.getAge(),0);
			}
		}
		
		// return proper sequence called listIterator,strat at the specified index 
		outPut.outPut("=======ListIterator(int index)========",0);
		ListIterator<Dog> lit2 = (ListIterator<Dog>) arraylist.listIterator(3);		
		while(lit2.hasNext()) {
			Dog dog = lit2.next();
			outPut.outPut(dog.getName(),1);
		}
		
		
		// use Arrays.copyOf() to copy this ArrayList belongs to shallow copying
		outPut.outPut("\n=======clone()=======",1);
		@SuppressWarnings("unchecked")
		ArrayList<Dog> array = (ArrayList<Dog>)arraylist.clone();
		// remove a element of this ArrayList 
		array.remove(1);
		// remove "john" element of this ArrayList
		array.remove(new Dog("john",21));
		// remove the range elements of this ArrayList		array.removeRange() not open to user
		array.subList(1, 3).clear();
		outPut.outPut("", 0);
		ListIterator<Dog> lit1 = (ListIterator<Dog>) array.listIterator();
		while(lit1.hasNext()) {
			Dog dog = lit1.next();
			outPut.outPut(dog.getName(),1);
		}
		// retain the union between arraylist and arraylist1
		outPut.outPut("", 0);
		outPut.outPut("=======retainAll(Collection<?> c)=======", 0);
		arraylist1.retainAll(arraylist);
		arraylist1.forEach(e->outPut.outPut(e));
		// arraylist remove arraylist1     remove the union between arraylist and  arraylist1
		outPut.outPut("", 0);
		outPut.outPut("=======removeAll(Collection<?> c)+removeIf(Predicate<? super E> filter) =======", 0);
		arraylist.removeAll(arraylist1);
		arraylist.removeIf(s -> s.getAge()%5==0); 
		arraylist.replaceAll(s->{
			s.setName(s.getName().toUpperCase());
			return s;
		});
		arraylist.forEach(e->outPut.outPut(e));
		
		// replace the element at the specified index of this ArrayList
		outPut.outPut("", 0);
		outPut.outPut("======= set(int index,E element) =======", 0);
		arraylist.set(0, new Dog("goudan",22));
		arraylist.forEach(s->outPut.outPut(s));
		
		//arraylist real length
		outPut.outPut("", 0);
		outPut.outPut("======= size() =======", 0);
		outPut.outPut(arraylist.size(),0);
		
		// sort this ArrayList by XXComparator 
		outPut.outPut("======= sort(Comparator<? extends E> c) =======", 0);
		DogComparator dcomparator = new DogComparator();
		arraylist.sort(dcomparator);
		arraylist.forEach(s->outPut.outPut(s,0));
		
		//TODO spliterator() 
		
		// toArray()
		outPut.outPut("======= toArray() =======", 0);
		Object a [] = arraylist.toArray();
		outPut.outPut(Arrays.toString(a), 0);
		
		// toArray(T[] a)
		outPut.outPut("======= toArray(T[] a) =======", 0);
		Dog [] dogArr = new Dog[arraylist.size()];
		arraylist.toArray(dogArr);
		outPut.outPut(Arrays.toString(dogArr), 0);
		
		//condense this ArrayList's capacity to real size.
		outPut.outPut("======= trimToSize() =======", 0);
		arraylist.trimToSize();
		ArrayListCapacity.ArrayListCapacity(arraylist);
	}
}

package cn.zhuj.util;

import java.lang.reflect.Field;
import java.util.ArrayList;

public class ArrayListCapacity {
    public static void ArrayListCapacity(ArrayList<?> arraylist) {
        Class<? extends Object> cls = ((Object)arraylist).getClass();
        Field field;
        try {
            field = cls.getDeclaredField("elementData");
            field.setAccessible(true);
            try {
                Object[] o = (Object[]) field.get(arraylist);
                outPut.outPut("object[]'s length is "+o.length,0);
            } catch (IllegalAccessException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        } catch (NoSuchFieldException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SecurityException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

package cn.zhuj.util;

import cn.zhuj.ArrayList1.Dog;

public class outPut {

    public static void outPut(Dog d) {
        // TODO Auto-generated method stub
        System.out.print(d.getName() + "\t");
    }
    
    public static void outPut(Object e ,int i) {
        // TODO Auto-generated method stub
        if (i == 0)
            System.out.println(e);
        else
            System.out.print(e+"\t");
    }
    public static void outPut(String s,Dog d) {
        System.out.print(s+d.getName() + "\t");
    }
}

package cn.zhuj.ArrayList1;

import java.util.Comparator;

public class DogComparator implements Comparator<Dog>{

    /* (non-Javadoc)
     * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
     */
    @Override
    public int compare(Dog o1, Dog o2) {
        // TODO Auto-generated method stub
        return o1.getAge()-o2.getAge();
    }

}


package cn.zhuj.ArrayList1;

public class Dog {
    private String name;
    private int age;
    /**
     * @return the name
     */
    public String getName() {
        return name;
    }
    /**
     * @param name the name to set
     */
    public void setName(String name) {
        this.name = name;
    }
    /**
     * @return the age
     */
    public int getAge() {
        return age;
    }
    /**
     * @param age the age to set
     */
    public void setAge(int age) {
        this.age = age;
    }
    /* (non-Javadoc)
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        // TODO Auto-generated method stub
        return this.name+"-"+this.age;
    }
    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @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;
    }
    /* (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Dog other = (Dog) 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 Dog(String name, int age) {
        super();
        this.name = name;
        this.age = age;
    }
    public Dog() {
        super();
        // TODO Auto-generated constructor stub
    }
    
}

 

 

转载于:https://www.cnblogs.com/zhju/p/8796639.html