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ArrayList?????????????ArrayList?????????????

???ArrayList?????????????(????????)

??????????????????????

?????

package cn.itcast_01;
import java.util.ArrayList;
import java.util.Iterator;
public class ArrayListTest {
    public static void main(String[] args) {
        // ??????
        ArrayList array = new ArrayList();
        // ?????????(???????)
        array.add("hello");
        array.add("world");
        array.add("java");
        array.add("world");
        array.add("java");
        array.add("world");
        array.add("world");
        array.add("world");
        array.add("world");
        array.add("java");
        array.add("world");
        // ???????????????
        for (int i = 0; i < array.size() - 1; i++) {
            for (int j = i + 1; j < array.size(); j++) {
                if (array.get(i).equals(array.get(j))) {
                    array.remove(j);
                    j--;
                }
            }
        }
        // ????
        Iterator it = array.iterator();
        while (it.hasNext()) {
            String s = (String) it.next();
            System.out.println(s);
        }
    }
}

3. ArrayList?????????????

?????????????????(???????????)

?????

• ?????????????????????
• ?????
• ?????????
• ????????????????????????
• ?????contains( )???????equals( )???
• ????Student????equals( )????????????????Object?equals( )???
• Object?equals( )??????????????????????
• ???????????????????equals( )??????????

?????

package cn.itcast_01;
import java.util.ArrayList;
import java.util.Iterator;
public class ArrayListTest2 {
    public static void main(String[] args) {
        // ??????
        ArrayList array = new ArrayList();
        // ??????
        Student s1 = new Student("???", 27);
        Student s2 = new Student("???", 40);
        Student s3 = new Student("??", 35);
        Student s4 = new Student("????", 18);
        Student s5 = new Student("??", 16);
        Student s6 = new Student("???", 27);
        Student s7 = new Student("???", 18);
        // ????
        array.add(s1);
        array.add(s2);
        array.add(s3);
        array.add(s4);
        array.add(s5);
        array.add(s6);
        array.add(s7);
        // ?????
        ArrayList newArray = new ArrayList();
        // ???????????????
        Iterator it = array.iterator();
        while (it.hasNext()) {
            Student s = (Student) it.next();
            // ????????????????
            if (!newArray.contains(s)) {
                newArray.add(s);
            }
        }
        // ????
        for (int x = 0; x < newArray.size(); x++) {
            Student s = (Student) newArray.get(x);
            System.out.println(s.getName() + "---" + s.getAge());
        }
    }
}
class Student {
    private String name;
    private int age;
    public Student() {
        super();
    }
    public Student(String name, int age) {
        super();
        this.name = name;
        this.age = 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;
    }
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Student other = (Student) 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;
    }
}

????????????ArrayList?????????????????????????????????????????Student??equals??????????????????????????