Java Comparator和Comparable接口的compare方法

最新推荐文章于 2025-06-24 08:30:00 发布

翻译最新推荐文章于 2025-06-24 08:30:00 发布 · 498 阅读

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本文介绍了一种通过实现Comparable接口和使用Comparator接口来进行对象排序的方法。具体展示了如何定义一个User类并实现Comparable接口来完成排序操作，同时提供了使用匿名内部类作为Comparator的例子。

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/**
 * Comparable接口的测试
 */
package testcomparable;

/**
 * @author quyang.ybb
 *
 */
public class User implements Comparable<User> {

    private String name;
    private Integer order;

    public String getName() {
	return name;
    }

    public void setName(String name) {
	this.name = name;
    }

    public Integer getOrder() {
	return order;
    }

    public void setOrder(Integer order) {
	this.order = order;
    }

    @Override
    public int compareTo(User arg0) {
	return this.getOrder().compareTo(arg0.getOrder());
    }

}

package testcomparable;

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

public class Test {

    public static void main(String[] args) {
	User user1 = new User();
	user1.setName("a");
	user1.setOrder(3);
	User user2 = new User();
	user2.setName("b");
	user2.setOrder(1);
	User user3 = new User();
	user3.setName("c");
	user3.setOrder(2);
	List<User> list = new ArrayList<User>();
	list.add(user1);
	list.add(user2);
	list.add(user3);
	Collections.sort(list);
	for (User u : list) {
	    System.out.println(u.getName());
	}
    }

}

package testcomparator;

public class User {
    private String name;
    private Integer order;

    public String getName() {
	return name;
    }

    public void setName(String name) {
	this.name = name;
    }

    public Integer getOrder() {
	return order;
    }

    public void setOrder(Integer order) {
	this.order = order;
    }
}

package testcomparator;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import testcomparable.User;

public class Test {

    public static void main(String[] args) {
	User user1 = new User();
	user1.setName("a");
	user1.setOrder(3);
	User user2 = new User();
	user2.setName("b");
	user2.setOrder(1);
	User user3 = new User();
	user3.setName("c");
	user3.setOrder(2);
	List<User> list = new ArrayList<User>();
	list.add(user1);
	list.add(user2);
	list.add(user3);
	Collections.sort(list, new Comparator<User>() {
	    @Override
	    public int compare(User o1, User o2) {
		return o1.getOrder().compareTo(o2.getOrder());
	    }

	});
	for (User u : list) {
	    System.out.println(u.getName());
	}
    }

}