ArrayList去重

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

public class ArrayList_Test {
    public static void main(String[] args) {
        List<Student> stus = new ArrayList<>();

        stus.add(new Student("zhangsan"));
        stus.add(new Student("lisi"));
        stus.add(new Student("zhangsan"));
        stus.add(new Student("zhangsan"));
        stus.add(new Student("wangwu"));
//   第一种
//        for (int i = 0; i < stus.size() - 1; i++) {
//            for (int j = i + 1; j < stus.size()-1; j++) {
//                if (stus.get(i).getName().equals(stus.get(j).getName())) {
//                    stus.remove(stus.get(i));
//                }
//            }
//        }
//        System.out.println(stus);
//        第二种
//        定义一个新集合
        List<Student> stus2 = new ArrayList<>();
        for (int i = 0; i < stus.size(); i++) {
            if (!stus2.contains(stus.get(i))) {// 内部调用了equals方法，所以比的是栈中的引用地址，所以要重写equals方法
                stus2.add(stus.get(i));
            }
        }
        System.out.println(stus2);

    }
}

class Student {
    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 [name=" + name + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }

    @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 (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }

}