17-集合框架-20-常用对象API(集合框架练习)

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package cn.itcast.bean.person;public class Person {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 Person(String name, int age) {super();this.name = name;this.age = age;}public Person() {super();}@Overridepublic boolean equals(Object obj) {if (this == obj) {return true;}if (!(obj instanceof Person)) {throw new ClassCastException("类型错误");}Person p = (Person) obj;return this.name.equals(p.name) && this.age == p.age;}}

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package cn.itcast.collection.test;

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

public class CollectionTest {

public static void main(String[] args) {

/*
* 【需求】
* 删除ArrayList中重复元素
*/
ArrayList al = new ArrayList();
al.add("abc1");
al.add("abc2");
al.add("abc2");
al.add("abc1");
al.add("abc");

System.out.println(al);
al=getSingleElement(al);
System.out.println(al);
}

public static ArrayList getSingleElement(ArrayList al) {

//1.定义一个临时容器
ArrayList temp = new ArrayList();

//2.遍历（迭代）al集合
Iterator it = al.iterator();
while(it.hasNext()){
Object obj = it.next();
//3.判断被迭代到的元素是否在临时容器中已有相同元素。
if(!(temp.contains(obj)))//如果不存在，才存入临时容器中
temp.add(obj);
}

return temp;
}

}

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package cn.itcast.collection.test;

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

import cn.itcast.bean.person.Person;

public class CollectionTest2 {

public static void main(String[] args) {

ArrayList al = new ArrayList();

al.add(new Person("lisi1", 21));
al.add(new Person("lisi2", 22));
al.add(new Person("lisi3", 23));
al.add(new Person("lisi4", 24));
al.add(new Person("lisi3", 23));
al.add(new Person("lisi4", 24));

printArrayList(al);
System.out.println("======================");

al = getSingleElement_2(al);

printArrayList(al);
}

public static void printArrayList(ArrayList al) {
Iterator i = al.iterator();
while (i.hasNext()) {
Person p = (Person) i.next();
System.out.println(p.getName() + "..." + p.getAge());
}
}

public static ArrayList getSingleElement_2(ArrayList al) {

ArrayList temp = new ArrayList();
Iterator it = al.iterator();
while (it.hasNext()) {
Object obj = it.next();
if (!(temp.contains(obj)))
temp.add(obj);
}
return temp;
}

}

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