Commons - BeanUtils 提供了很多功能，其中一个很有用的是对对象集合进行排序，如Collections.sort(peoples, new BeanComparator("age"));

另外，可以使用java.util.Collections的sort方法可以对collection集合进行排序，包括多列组合排序，下面是自己实现java.util.Comparator，定制对象属性排序规则的例子：

package com.lph.test;

import java.util.Comparator;

import java.util.Iterator;

import java.util.List;

import java.util.LinkedList;

/**

*

* 自定义对象多属性(多列)组合排序

*

Title: is a Class

*

*

Description: 类

*

*

Copyright: Copyright (c) 2006

*

*

Company: sunrise

*

* @author islph

* @version 1.0

*/

public class CompositeComparator implements Comparator {

/** in the condition list, comparators' priority decrease from head to tail */

private List comparators = new LinkedList();

/** get the comparators, you can manipulate it as need. */

public List getComparators() {

return comparators;

}

/** add a batch of comparators to the condition list */

public void addComparators(Comparator[] comparatorArray) {

if (comparatorArray == null) {

return;

}

for (int i = 0; i < comparatorArray.length; i++) {

comparators.add(comparatorArray[i]);

}

}

/** compare by the priority */

public int compare(Object o1, Object o2) {

for (Iterator iterator = comparators.iterator(); iterator.hasNext();) {

Comparator comparator = (Comparator) iterator.next();

int result = comparator.compare(o1, o2);

if (result != 0) {

return result;

}

}

return 0;

}

}

// 多列排序；按属性COUNTY_NO镇，DDP_ID终端 组合排序

CompositeComparator myComparator = new CompositeComparator();

myComparator.addComparators(

new Comparator[] {

new Comparator() {

public int compare(Object a, Object b) {

DisplayForm aObj, bObj;

aObj = (DisplayForm) a;

bObj = (DisplayForm) b;

String aStr = (String) aObj.get("COUNTY_NO");

String bStr = (String) bObj.get("COUNTY_NO");

return aStr.compareTo(bStr);

}

}

, new Comparator() {

public int compare(Object a, Object b) {

DisplayForm aObj, bObj;

aObj = (DisplayForm) a;

bObj = (DisplayForm) b;

String aStr = (String) aObj.get("DDP_ID");

String bStr = (String) bObj.get("DDP_ID");

return aStr.compareTo(bStr);

}

}

});

java.util.Collections.sort(listResult, myComparator);

标签 :java

IT瘾于2006年10月13日 下午11时03分42秒发布

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