/*** Java對象排序的3種實現方式*/
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)實現，必須實現Comparator的一個比較器并復寫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)類來比較：");
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[])實現,對象必須實現Comparable接口并復寫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[])類來比較：");
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)實現，對象必須實現Comparable接口并復寫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)類來比較：");
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
*/
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
*/
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
*/
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;
}
}