工作中遇到按照类的某个属性排列，这个属性是个枚举类型，按照要求的优先级排列。
可以使用ComparatorChain、BeanComparator、FixedOrderComparator实现。
举一个例子：
学生类：包含姓名、年龄、性别、性格。性格是个枚举类型。
性格类：枚举类型，分为四类：内向，外向，太监，不知道四种类型。
SortUtil类：排序类。
Student.java
import java.util.ArrayList;import java.util.List;public class Student {private String name;private int age;private boolean sex;private Character character;public Student(String name, int age, boolean sex, Character character){this.name = name;this.age = age;this.sex = sex;this.character = character;}public void setName(String name) {this.name = name;}public String getName() {return name;}public void setAge(int age) {this.age = age;}public int getAge() {return age;}public void setSex(boolean sex) {this.sex = sex;}public boolean getSex() {return sex;}public void setCharacter(Character character) {this.character = character;}public Character getCharacter() {return character;}@Overridepublic String toString() {String sexString = sex == false ? "male" : "female";return "名字：" + name + " 年龄: " + age + " 性别: " + sexString + " 性格: " + character;}public static void main(String args[]) {Student student1 = new Student("spring", 20, false, Character.IN);Student student2 = new Student("summer", 18, false, Character.OUT );Student student3 = new Student("automn", 25, false, Character.UNKNOWN );Student student4 = new Student("winter", 25, true, Character.UNKNOWN);List<Student> list1 = new ArrayList<Student>();list1.add(student1);list1.add(student3);list1.add(student2);list1.add(student4);System.out.println("没有排序之前：");for(Student student : list1) {System.out.println(student);}SortUtil.sortByWhat(list1);System.out.println("排序之后：");for(Student student : list1) {System.out.println(student);}}}
Character类：
public enum Character {IN("内向"),OUT("外向"),BOTH("太监"),UNKNOWN("不知道");private String name;private Character(String name) {this.name = name;}public String getName() {return name;}public String toString() {return name;}}SortUtil类：import java.util.Collections;import java.util.Comparator;import java.util.List;import org.apache.commons.beanutils.BeanComparator;import org.apache.commons.collections.comparators.ComparatorChain;import org.apache.commons.collections.comparators.FixedOrderComparator;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;public class SortUtil {private static final Log Logger = LogFactory.getLog(SortUtil.class);@SuppressWarnings("unchecked")public static void sortByWhat(List<Student> list){try{Character[] CharacterType = {Character.UNKNOWN,Character.IN ,Character.OUT,Character.BOTH};Comparator TypeComparator = new FixedOrderComparator(CharacterType);ComparatorChain moInfoComparator = new ComparatorChain();moInfoComparator.addComparator(new BeanComparator("character",TypeComparator));moInfoComparator.addComparator(new BeanComparator("age"),true);moInfoComparator.addComparator(new BeanComparator("name"));moInfoComparator.addComparator(new BeanComparator("sex"));Collections.sort(list, moInfoComparator);} catch (Exception e) {Logger.error(e.getMessage());}}}moInfoComparator.addComparator(new BeanComparator("character",TypeComparator));
这个类中首先按照性格属性来排序，利用FixedOrderComparator设置优先级，性格属性Character.UNKOWN排第一，
然后IN，其次OUT，，最后BOTH。如果性格属性相同，按照age排序，true表示逆序（默认排序是从小到大），然后按
照name，最后按照sex属性排序。
需要导入commons-beanutils,commons-logging,commons-collections包。
结果：
可以看到排序之后首先按照性格排序，性格是枚举类型，排序规则用FixedOrderComparator定义，性格相同按照年龄，所以：
<span style="white-space:pre"></span>moInfoComparator.addComparator(new BeanComparator("character",TypeComparator));moInfoComparator.addComparator(new BeanComparator("age"),true);moInfoComparator.addComparator(new BeanComparator("name"));moInfoComparator.addComparator(new BeanComparator("sex"));这四句话的顺序决定了先已哪个属性排序。
没有伞的孩子必须努力奔跑!
