浅谈TreeSet中的两种排序方式_JAVA教程

浅谈TreeSet中的两种排序方式

2020-09-23 13:37Java教程网 JAVA教程

下面小编就为大家带来一篇浅谈TreeSet中的两种排序方式。小编觉得挺不错的，现在就分享给大家，也给大家做个参考。一起跟随小编过来看看吧

直接上代码：

									package exercise1;

									public class Person implements Comparable{

									  private int id;

									  private String name;

									  public Person(int id, String name) {

									    super();

									    this.id = id;

									    this.name = name;

									  }

									  public int getId() {

									    return id;

									  }

									  public void setId(int id) {

									    this.id = id;

									  }

									  public String getName() {

									    return name;

									  }

									  public void setName(String name) {

									    this.name = name;

									  }

									  public String toString() {

									    return "Person [id=" + id + ", name=" + name + "]";

									  }

									  public int hashCode() {

									    final int prime = 31;

									    int result = 1;

									    result = prime * result + id;

									    result = prime * result + ((name == null) ? 0 : name.hashCode());

									    return result;

									  }

									  public boolean equals(Object obj) {

									    if (this == obj)

									      return true;

									    if (obj == null)

									      return false;

									    if (getClass() != obj.getClass())

									      return false;

									    Person other = (Person) obj;

									    if (id != other.id)

									      return false;

									    if (name == null) {

									      if (other.name != null)

									        return false;

									    } else if (!name.equals(other.name))

									      return false;

									    return true;

									  }

									  public int compareTo(Object o) {

									    if(o instanceof Person){

									      Person p=(Person)o;

									      return this.name.compareTo(p.name);

									    }

									    return 0;

									  }

									}

									package exercise1;

									//TreeSet下的自然排序和定制排序

									import java.util.Comparator;

									import java.util.Iterator;

									import java.util.Set;

									import java.util.TreeSet;

									import java.util.function.Function;

									import java.util.function.ToDoubleFunction;

									import java.util.function.ToIntFunction;

									import java.util.function.ToLongFunction;

									import org.junit.Test;

									//定制排序

									public class DisOrder {

									  @Test

									  public void unNature(){

									    Comparator com=new Comparator() {

									      public int compare(Object o1, Object o2) {

									        if(o1 instanceof Person && o2 instanceof Person){

									          Person p1=(Person)o1;

									          Person p2=(Person)o2;

									          return p1.getName().compareTo(p2.getName());

									        }

									        return 0;

									      }

									    };

									    Set set=new TreeSet(com);

									    set.add(new Person(111,"MM"));

									    set.add(new Person(222,"DD"));

									    set.add(new Person(333,"GG"));

									    for(Object obj:set){

									      System.out.println(obj);

									    }

									  }

									  //自然排序

									  @Test

									  public void nature() {

									    Set set=new TreeSet();

									    set.add("aa");

									    set.add("bb");

									    set.add("ff");

									    set.add("zz");

									    for(Object obj:set){

									      System.out.println(obj);

									    }

									  }

									}