Java连载85-集合的Contains和Remove方法

package com.bjpowernode.java_learning;

import java.util.*;

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public class D85_1_ContainsMethod {

  public static void main(String[] args) {

    //创建集合

    Collection c = new ArrayList();

    //创建两个Integer类型的对象

    Integer i1 = new Integer(10);

    //添加元素

    c.add(i1);

    //判断集合中是否包含11

    System.out.println(c.contains(i1));

    ///创建Integer类型的对象

    Integer i2 = new Integer(10);

    System.out.println(c.contains(i2));

    //这里包含了i2说明了，contains底层调用了equals方法。如果equals返回了true，就是包含

   

    Manager85 m1 = new Manager85(52,"jho");

    c.add(m1);

    Manager85 m2 = new Manager85(52,"jho");

    System.out.println(c.contains(m2));

   

  }

}

class Manager85{

  int no;

  String name;

  Manager85(int no,String name){

    this.no = no;

    this.name = name;

  }

  public boolean equals(Object o){

    if(this==o) return true;

    if(o instanceof Manager85) {

      Manager85 m = (Manager85)o;

      if(this.no==m.no && this.name.equals(m.name)){

        return true;

      }

    }

    return false;

  }

  //总结创建一个类，要重写equals方法，才能对类中的数据进行对比，否则继承原来的equals只能是对比对象的地址

}

package com.bjpowernode.java_learning;

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import java.util.*;

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public class D85_2_RemoveMethod {

  public static void main(String[] args) {

    //创建集合对象

    Collection c = new ArrayList();

   

    Integer i1 = new Integer(10);

    //添加元素

    c.add(i1);

    //删除

    Integer i2 = new Integer(10);

    c.remove(i2);

   

    System.out.println(c.size());

    Manager85 m1 = new Manager85(10,"ji");

    c.add(m1);

    Manager85 m2 = new Manager85(10,"ji");

    c.remove(m2);

    System.out.println(c.size());

  }

}

package com.bjpowernode.java_learning;

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import java.util.*;

import java.lang.Iterable;

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public class D85_3_DeepIntoRemoveMethod {

  public static void main(String[] args) {

    Collection c = new ArrayList();

    c.add(1);//这里复习了自动装箱，int类型直接转化为Integer类型

    c.add(2);

    c.add(3);

    //遍历

    Iterator it = c.iterator();

    while(it.hasNext()) {

      Object element = it.next();

      //删除

      it.remove();//通过迭代器的remove方法删除

    }

    System.out.println(c.size());

    Collection c2 = new ArrayList();

    c2.add(1);//这里复习了自动装箱，int类型直接转化为Integer类型

    c2.add(2);

    c2.add(3);

    Iterator it2 = c2.iterator();

    while(it2.hasNext()) {

      Object element = it2.next();

      c2.remove(element);

    }  

  }

}