Java List根据多个参数排序

依赖（commons-collections-3.2.1.jar和commons-beanutils-1.8.2.jar）：
import java.util.Collections;
import java.util.Comparator;

import org.apache.commons.beanutils.BeanComparator;
import org.apache.commons.collections.ComparatorUtils;
import org.apache.commons.collections.comparators.ComparableComparator;
import org.apache.commons.collections.comparators.ComparatorChain;

代码：
Comparator myCom1 = ComparableComparator.getInstance();
Comparator myCom2 = ComparableComparator.getInstance ();
myCom1= ComparatorUtils. nullHighComparator(myCom1); //允许null
myCom2 = ComparatorUtils. nullHighComparator(myCom2); //允许null
//默认为正序，可选择设置为逆序
//myCom1 = ComparatorUtils.reversedComparator(myCom1);
//myCom2 = ComparatorUtils.reversedComparator(myCom2);
ArrayList<Object> sortFields = new ArrayList<Object>();
sortFields.add( new BeanComparator("age" , myCom1)); //第一排序
sortFields.add( new BeanComparator("classes" , myCom2)); //第二排序
//创建一个排序链
ComparatorChain multiSort = new ComparatorChain(sortFields);
Collections.sort(list, multiSort);