Comparator比较器对ArrayList排序

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);
}



}

}


首发于 - http://java-er.com/blog/comparator-sort-arraylist/