Java中List的排序

第一种方法，就是list中对象实现Comparable接口，代码如下：

+ View Code?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

public class Person implements Comparable<Person> {     private String name;     private Integer order;       /**      * @return the name      */     public String getName() {         return name;     }       /**      * @param name      *            the name to set      */     public void setName(String name) {         this.name = name;     }       /**      * @return the order      */     public Integer getOrder() {         return order;     }       /**      * @param order      *            the order to set      */     public void setOrder(Integer order) {         this.order = order;     }       @Override     public int compareTo(Person arg0) {         return this.getOrder().compareTo(arg0.getOrder());     }   }

+ View Code?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

public static void main(String[] args) {     List<Person> listA = new ArrayList<Person>();     Person p1 = new Person();     Person p2 = new Person();     Person p3 = new Person();       p1.setName("name1");     p1.setOrder(1);     p2.setName("name2");     p2.setOrder(2);     p3.setName("name3");     p3.setOrder(3);       listA.add(p2);     listA.add(p1);     listA.add(p3);     Collections.sort(listA);     for (Person p : listA) {         System.out.println(p.getName());     } }

第二种方法，就是在重载Collections.sort方法，代码如下：

+ View Code?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

public class Person {     private String name;     private Integer order;       /**      * @return the name      */     public String getName() {         return name;     }       /**      * @param name      *            the name to set      */     public void setName(String name) {         this.name = name;     }       /**      * @return the order      */     public Integer getOrder() {         return order;     }       /**      * @param order      *            the order to set      */     public void setOrder(Integer order) {         this.order = order;     }   }

+ View Code?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

public static void main(String[] args) {         List<Person> listA = new ArrayList<Person>();         Person p1 = new Person();         Person p2 = new Person();         Person p3 = new Person();           p1.setName("name1");         p1.setOrder(1);         p2.setName("name2");         p2.setOrder(2);         p3.setName("name3");         p3.setOrder(3);           listA.add(p2);         listA.add(p1);         listA.add(p3);                   Collections.sort(listA, new Comparator<Person>() {             public int compare(Person arg0, Person arg1) {                 return arg0.getOrder().compareTo(arg1.getOrder());             }         });                   for (Person p : listA) {             System.out.println(p.getName());         }     }

两次执行的结果都是：

name1

name2

name3