java基础 -- Collections.sort的两种用法

/**
* @author
* @version
* 类说明
*/
package com.jabberchina.test;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public class SortTest {
public static void main(String[] args) {
List<String> lists = new ArrayList<String>();
List<A> list = new ArrayList<A>();
List<B> listB = new ArrayList<B>();
lists.add("5");
lists.add("2");
lists.add("9");
//lists中的对象String 本身含有compareTo方法，所以可以直接调用sort方法，按自然顺序排序，即升序排序
Collections.sort(lists);
A aa = new A();
aa.setName("aa");
aa.setOrder(1);
A bb = new A();
bb.setName("bb");
bb.setOrder(2);
list.add(bb);
list.add(aa);
//list中的对象A实现Comparable接口
Collections.sort(list);
B ab = new B();
ab.setName("ab");
ab.setOrder("1");
B ba = new B();
ba.setName("ba");
ba.setOrder("2");
listB.add(ba);
listB.add(ab);
//根据Collections.sort重载方法来实现
Collections.sort(listB,new Comparator<B>(){
@Override
public int compare(B b1, B b2) {
return b1.getOrder().compareTo(b2.getOrder());
}
});
System.out.println(lists);
System.out.println(list);
System.out.println(listB);
}
}
class A implements Comparable<A>{
private String name;
private Integer order;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getOrder() {
return order;
}
public void setOrder(Integer order) {
this.order = order;
}
@Override
public String toString() {
return "name is "+name+" order is "+order;
}
@Override
public int compareTo(A a) {
return this.order.compareTo(a.getOrder());
}
}
class B{
private String name;
private String order;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getOrder() {
return order;
}
public void setOrder(String order) {
this.order = order;
}
@Override
public String toString() {
return "name is "+name+" order is "+order;
}
}
打印的结果为：
[2, 5, 9]
[name is aa order is 1, name is bb order is 2]
[name is ab order is 1, name is ba order is 2]

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java基础 -- Collections.sort的两种用法

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