Java对象排序的3种实现方式，java对象排序3种,/** * Java对象

Java对象排序的3种实现方式，java对象排序3种,/** * Java对象

/** * Java对象排序的3种实现方式 * @author zhangwenzhang * */public class TestObjectSort {    /**     * @param args     */    public static void main(String[] args) {        // TODO Auto-generated method stub        /**方法1         * 使用Collections.sort(List, Comparator)实现，必须实现Comparator的一个比较器并复写compare()方法         */        Person1[] ps = new Person1[]{new Person1("p0",0),                                     new Person1("p1",3),                                     new Person1("p2",5),                                     new Person1("p3",4),                                     new Person1("p4",8),                                     new Person1("p5",6),                                     new Person1("p6",7),                                     new Person1("p7",1),                                     new Person1("p8",2),                                     new Person1("p9",9)};        List<Person1> pl = new ArrayList<Person1>();        for(int i = 0; i < 10; i++){            System.out.print(ps[i].getAge());            pl.add(ps[i]);        }        System.out.println("\n使用Collections.sort(List, Comparator)类来比较：");        long l1 = System.currentTimeMillis();        Collections.sort(pl, new MyComparator());        System.out.println("time: " + (System.currentTimeMillis() - l1));        for(Iterator it = pl.iterator(); it.hasNext();){            Person1 p = (Person1) it.next();            System.out.print(p.getAge());        }        /**方法2         * 使用Arrays.sort(Object[])实现,对象必须实现Comparable接口并复写compareTo()方法         */        Person2[] ps2 = new Person2[]{new Person2("p0",0),                                     new Person2("p1",3),                                     new Person2("p2",5),                                     new Person2("p3",4),                                     new Person2("p4",8),                                     new Person2("p5",6),                                     new Person2("p6",7),                                     new Person2("p7",1),                                     new Person2("p8",2),                                     new Person2("p9",9)};        System.out.println("\n使用Arrays.sort(Object[])类来比较：");        long l2 = System.currentTimeMillis();        Arrays.sort(ps2);        System.out.println("time: " + (System.currentTimeMillis() - l2));        for(int i = 0; i < 10; i++){            System.out.print(ps2[i].getAge());        }        /**方法3         * 使用Collections.sort(List)实现，对象必须实现Comparable接口并复写compareTo()方法         */        Person2[] ps3 = new Person2[]{new Person2("p0",0),                                     new Person2("p1",3),                                     new Person2("p2",5),                                     new Person2("p3",4),                                     new Person2("p4",8),                                     new Person2("p5",6),                                     new Person2("p6",7),                                     new Person2("p7",1),                                     new Person2("p8",2),                                     new Person2("p9",9)};        List<Person2> pl3 = new ArrayList<Person2>();        for(int i = 0; i < 10; i++){            pl3.add(ps3[i]);        }        System.out.println("\n使用Collections.sort(List)类来比较：");        Collections.sort(pl3);        for(Iterator it = pl3.iterator(); it.hasNext();){            Person2 p = (Person2) it.next();            System.out.print(p.getAge());        }    }}/** * 方法1需要 * @author zhangwenzhang * */class MyComparator implements Comparator{    public int compare(Object o1, Object o2){        Person1 p1 = (Person1)o1;        Person1 p2 = (Person1)o2;        if(p1.getAge() < p2.getAge()){            return -1;        }else if(p1.getAge() == p2.getAge()){            return 0;        }else{            return 1;        }    }}/** * 方法1需要 * @author zhangwenzhang * */class Person1{    private String name;    private int age;    public Person1(){}    public Person1(String name, int age) {        super();        this.name = name;        this.age = age;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }}/** * 方法2,3需要 * @author zhangwenzhang * */class Person2 implements Comparable{    private String name;    private int age;    public Person2(){}    public Person2(String name, int age) {        super();        this.name = name;        this.age = age;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    public int compareTo(Object o){        Person2 p = (Person2)o;        if(this.age < p.age){            return -1;        }else if(this.age == p.age){            return 0;        }else{            return 1;        }    }}