boy 男生 对象

package com.javaer.examples.sort;public class Boy {	String name;//姓名	int score;// 分数	public String getName() {		return name;	}	public void setName(String name) {		this.name = name;	}	public int getScore() {		return score;	}	public void setScore(int score) {		this.score = score;	}}

Comparator强行对某个对象collection进行整体排序的比较函数，可以将Comparator传递给Collections.sort或Arrays.sort。

比较算法

package com.javaer.examples.sort; import java.util.Comparator; public class MyComparator implements Comparator {
     	//接口，必须实现的方法 	public int compare(Object o1, Object o2) {
     		Boy p1 = (Boy) o1; 		Boy p2 = (Boy) o2; 		if (p1.score < p2.score) 			return 1; 		else if (p1.score > p2.score) 			return -1; 		else 			return 0; 	} }

实际运用

package com.javaer.examples.sort; import java.util.ArrayList; import java.util.Collections; import java.util.List; public class ScoreSort{
     	/** 	 * @param args 	 */ 	public static void main(String[] args) {
     		List boys = new ArrayList(); 		Boy b = new Boy(); 		b.name = ‘‘tom‘‘; 		b.score = 89; 		boys.add(b); 		b = new Boy(); 		b.name = ‘‘jim‘‘; 		b.score = 92; 		boys.add(b); 		b = new Boy(); 		b.name = ‘‘jack‘‘; 		b.score = 77; 		boys.add(b); 		for(int i=0 ;i < boys.size();i++){
     			b = (Boy)boys.get(i); 			System.out.println(b.name + ‘‘ : ‘‘ + b.score); 		} 		System.out.println(‘‘------------------------‘‘); 		MyComparator mc = new MyComparator(); 		Collections.sort(boys,mc);  		for(int i=0 ;i < boys.size();i++){
     			b = (Boy)boys.get(i); 			System.out.println(b.name + ‘‘ : ‘‘ + b.score); 		} 	} }

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