课堂题目

蔚落 2022-10-03 00:37 145阅读 0赞

## 第一种方法： ##

**Student:**

package com.test2;
    
    public class Student implements Comparable<Student> {
    	public  String name;
    	public  int score;
    	public Student(String name, int score) {
    		super();
    		this.name = name;
    		this.score = score;
    	}
    	/**
    	 * @return the name
    	 */
    	public String getName() {
    		return name;
    	}
    	/**
    	 * @param name the name to set
    	 */
    	public void setName(String name) {
    		this.name = name;
    	}
    	/**
    	 * @return the score
    	 */
    	public int getScore() {
    		return score;
    	}
    	/**
    	 * @param score the score to set
    	 */
    	public void setScore(int score) {
    		this.score = score;
    	}
    	@Override
    	public int compareTo(Student o) {
    		// TODO Auto-generated method stub
    		//返回值小于0：与前面换位
    		//返回值等于0：不变
    		//返回值大于0：放后面
    		return this.score-o.score;
    	}
    	@Override
    	public String toString() {
    		return "Student [name=" + name + ", score=" + score + "]";
    	}
    
    }

Test类：

package com.test2;
    
    import java.util.ArrayList;
    import java.util.Collection;
    import java.util.Collections;
    
    
    public class Test {
    
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    		ArrayList<Student> arrayList=new ArrayList<Student>();
    		Student s1=new Student("桂贤松", 56);
    		Student s2=new Student("王震宇", 87);
    		Student s3=new Student("何明雨", 67);
    		Student s4=new Student("王长坤", 32);
    		
    		arrayList.add(s1);
    		arrayList.add(s2);
    		arrayList.add(s3);
    		arrayList.add(s4);
    		
    		
    		Collections.sort(arrayList);
    		System.out.println(arrayList);
    	}
    
    }

## 第二种方法实现： ##

Student类：

package com.test3;
    
    public class Student{
    	public  String name;
    	public  int score;
    	public Student(String name, int score) {
    		super();
    		this.name = name;
    		this.score = score;
    	}
    	/**
    	 * @return the name
    	 */
    	public String getName() {
    		return name;
    	}
    	/**
    	 * @param name the name to set
    	 */
    	public void setName(String name) {
    		this.name = name;
    	}
    	/**
    	 * @return the score
    	 */
    	public int getScore() {
    		return score;
    	}
    	/**
    	 * @param score the score to set
    	 */
    	public void setScore(int score) {
    		this.score = score;
    	}
    
    	@Override
    	public String toString() {
    		return "Student [name=" + name + ", score=" + score + "]";
    	}
    
    }

Test类：

package com.test3;
    
    import java.util.ArrayList;
    import java.util.Collection;
    import java.util.Collections;
    import java.util.Comparator;
    public class Test {
    
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    		ArrayList<Student> arrayList=new ArrayList<Student>();
    		Student s1=new Student("桂贤松", 56);
    		Student s2=new Student("王震宇", 87);
    		Student s3=new Student("何明雨", 67);
    		Student s4=new Student("王长坤", 32);
    		
    		arrayList.add(s1);
    		arrayList.add(s2);
    		arrayList.add(s3);
    		arrayList.add(s4);
    		
    		
    		Collections.sort(arrayList, new Comparator<Student>() {
    			@Override
    			public int compare(Student o1, Student o2) {
    				// TODO Auto-generated method stub
    				return o2.getScore()-o1.getScore();
    			}
    		});
    		System.out.println(arrayList);
    	}
    
    }