Java-集合案例一

1、创建多个Student对象，使用集合Collection进行保存， 使用Iterator和增强for进行遍历输出，并输出集合中有多少个值。

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


public class Student {
	private String name;
	
	public Student(String name) {
		this.name = name;
	}
	
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@Override
	public String toString() {
		return "Student[姓名:" + name + "]";
	}
}

public class Work01 {
	public static void main(String[] args) {
		Collection student = new ArrayList();

		//向集合中添加元素
		student.add("张三");
		student.add("李四");
		student.add("王五");
		student.add("赵六");
		
		//获取迭代器的实现类对象
		Iterator iterator = student.iterator();
		System.out.println("使用Iterator输出集合元素为:");
		while (iterator.hasNext()) {
			System.out.print(iterator.next()+"t");
		}
		System.out.println();
		
		System.out.println("使用增强for输出集合元素为:");
		for(String s:student) {
			System.out.print(s+"t");
		}		
		System.out.println();
		System.out.println("集合中数值个数为:"+student.size());
		
	}
}

2.创建多个Student对象，使用集合Collection进行保存，删除后遍历输出，在清空，后判断是否为空。

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


public class Student {
	private String name;
	
	public Student(String name) {
		this.name = name;
	}
	
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@Override
	public String toString() {
		return "Student[姓名:" + name + "]";
	}
}

public class Work02 {
	public static void main(String[] args) {
		Collection student = new ArrayList();

		//向集合中添加元素
		student.add("张三");
		student.add("李四");
		student.add("王五");
		student.add("赵六");
		
		System.out.println(student);
		
		//删除后遍历输出
		student.remove("张三");
		System.out.println(student);
		
		//清空
		student.clear();
		System.out.println(student.isEmpty());
		
	}
}

3、创建多个Student对象，使用集合List集合保存，进行添加、以下标添加、以下标获取对象并输出，以下标删除，以下标修改值。 add(int index, Object o)

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


public class Student {
	private String name;
	
	public Student(String name) {
		this.name = name;
	}
	
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@Override
	public String toString() {
		return "Student[姓名:" + name + "]";
	}
}

public class Work03 {
	public static void main(String[] args) {
		List list = new ArrayList();

        //以下标添加对象
		list.add(0,new Student("张三"));
		list.add(1,new Student("李四"));
		list.add(2,new Student("王五"));
		list.add(3,new Student("赵六"));

        //以下标获取对象并输出
        System.out.println(list.get(1));
        System.out.println();

        //以下标删除对象
        list.remove(2);
        for (Object object:list) {
            Student s = (Student)object;
            System.out.println(s);
        }
        System.out.println();

        //以下标修改对象
        list.set(0,new Student("钱七"));
        System.out.println(list.get(0));
        System.out.println();
			
	}
	
}

4、创建多个Student对象，使用集合ArraysList集合保存，进行添加、以下标添加、以下标获取对象并输出，以下标删除，以下标修改值。

import java.util.ArrayList;


public class Student {
	private String name;
	
	public Student(String name) {
		this.name = name;
	}
	
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@Override
	public String toString() {
		return "Student[姓名:" + name + "]";
	}
}

public class Work04 {
	public static void main(String[] args) {
		ArrayList arrayList = new ArrayList();	

        //以下标添加对象
        arrayList.add(0,new Student("张三"));
        arrayList.add(1,new Student("李四"));
        arrayList.add(2,new Student("王五"));
        arrayList.add(3,new Student("赵六"));

        //以下标获取对象并输出
        System.out.println(arrayList.get(1));
        System.out.println();

        //以下标删除对象
        arrayList.remove(2);
        for (Object object:arrayList) {
            Student s = (Student)object;
            System.out.println(s);
        }
        System.out.println();

        //以下标修改对象
        arrayList.set(0,new Student("孙七"));
        System.out.println(arrayList.get(0));
        System.out.println();
	}
}

5、创建多个Student对象，使用集合linkedList集合保存，进行添加、以下标添加、以下标获取对象并输出，以下标删除，以下标修改值。 使用addLast/addFirst/removeFirst/removeLast等方法。

import java.util.linkedList;
import java.util.ListIterator;


public class Student {
	private String name;
	
	public Student(String name) {
		this.name = name;
	}
	
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@Override
	public String toString() {
		return "Student[姓名:" + name + "]";
	}
}
public class Work05 {
	public static void main(String[] args) {
		linkedList linkedList = new linkedList();
		
		//以下标添加对象
        linkedList.add(0,new Student("张三"));
        linkedList.add(1,new Student("李四"));
        linkedList.add(2,new Student("王五"));
        linkedList.add(3,new Student("赵六"));
		
        //以下标获取对象
        System.out.println(linkedList.get(2));
        System.out.println();
        
        //以下标删除对象
        linkedList.remove(1);
        for (int i = 0; i < linkedList.size(); i++) {
            Student s = (Student) linkedList.get(i);
            System.out.println(s);
        }
        System.out.println();
        
        //以下标修改对象
        linkedList.set(2,new Student("钱七"));
        ListIterator ite = linkedList.listIterator();
        while (ite.hasNext()){
            Student s = (Student) ite.next();
            System.out.println(s);
        }
        System.out.println();
        
        //使用addLast/addFirst/removeFirst/removeLast等方法
        linkedList.addFirst(new Student("周一"));
        linkedList.addLast(new Student("李八"));
        for (Object obj:linkedList) {
            Student s = (Student) obj;
            System.out.println(s);
        }
        System.out.println();

        //移除第一个与最后一个对象
        linkedList.removeFirst();
        linkedList.removeLast();

        for (int i = 0; i < linkedList.size(); i++) {
           Student s = (Student) linkedList.get(i);
            System.out.println(s);
        }
        
	}
}

6. 创建一个 List，在 List 中增加三个工人，Worker 类基本信息如下...

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



class Worker{
	private String name;
	private int age;
	private int salary;
	
	public Worker(String name,int age,int salary) {
		this.name = name;
		this.age = age;
		this.salary = salary;
	}
	
	@Override
	public String toString() {
		return "姓名:" + name + ", 年龄:" + age + ", 在工作工资为:" + salary;
	}
	
	@Override
	public boolean equals(Object obj) {
		if(obj instanceof Worker) {
			Worker worker = (Worker)obj;
			if(this.name==(worker.name)&&this.age==(worker.age)) {
				return true;
			}
		}
		return false;
	}

	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 int getSalary() {
		return salary;
	}
	public void setSalary(int salary) {
		this.salary = salary;
	}
}

public class Work06 {
	public static void main(String[] args) {
		List list = new ArrayList();
		
		list.add(new Worker("张三",18,3000));
		list.add(new Worker("李四",20,5000));
		list.add(new Worker("王五",22,10000));
		
		//在李四之前插入一个工人，信息为：姓名：赵六，年龄：24，工资 3300
		list.add(1, new Worker("赵六", 24, 3300));
		//利用 for 循环遍历，打印 List 中所有工人的信息
		for (int i = 0; i < list.size(); i++) {
			System.out.println(list.get(i));
		}
		System.out.println();
		
		//删除 王五的信息
		list.remove(3);
		//用 for-each 遍历，对 List 中所有的工人调用 work 方法
		for(Worker w:list) {
			System.out.println(w);
		}
		System.out.println();
		
		//为 Worker 类添加 equals 方法,判断姓名和年龄都一样即为同一人
		Worker worker1 = new Worker("张三", 18, 6000);
		if(worker1.equals(list.get(0))) {
			System.out.println("是同一人!");
		}else {
			System.out.println("不是同一人!");
		}
		
		
	}
}