Java Collections.sort()排序代码案例
1、案例:
Person对象(名字,id,年龄)
要求按照,年龄从小到大排序,年龄相等,按照名字的字典顺序de倒序排序
2、案例设计:
1)使用ArrayList存储Person对象,
2)利用Collections.sort()进行排序
3)输出结果
3、代码分享:
package CollectionDemo; import java.util.ArrayList; import java.util.Collections; import java.util.List; import java.util.Comparator; class Person{ private int id; private int age; private String name; public Person(int id, int age,String name){ this.id=id; this.age=age; this.name=name; } public void setId(int id) { this.id = id; } public void setAge(int age) { this.age = age; } public void setName(String name){ this.name=name; } public int getId() { return id; } public int getAge() { return age; } public String getName() { return name; } @Override public String toString() { return "Person{" + "id=" + id + ", age=" + age + ", name='" + name + '\'' + '}'; } } public class CollectionDemo2 { public static void main(String[] args){ List<Person> arrayList =new ArrayList<>(); arrayList.add(new Person(001,20,"yang")); arrayList.add(new Person(002,20,"zhang")); arrayList.add(new Person(003,30,"li")); arrayList.add(new Person(004,40,"Coco")); arrayList.add(new Person(005,40,"Marry")); Collections.sort(arrayList,new Comparator<Person>(){ public int compare(Person o1,Person o2){ if(o1.getAge()!=o2.getAge()){ return o1.getAge()-o2.getAge();//按照年龄升序排序 }else{ return o2.getName().compareToIgnoreCase(o1.getName());//按照名字的字典顺序倒序排序 } } }); //输出 for(Person p:arrayList){ System.out.println(p); } } }
输出:
Person{id=2, age=20, name='zhang'}
Person{id=1, age=20, name='yang'}
Person{id=3, age=30, name='li'}
Person{id=5, age=40, name='Marry'}
Person{id=4, age=40, name='Coco'}
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