compareTo 用法

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.List;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

public class Test implements Comparable<Test> {

private int id;

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public Test(int id) {

this.id = id;

}

public static void main(String[] args) {

List<Test> list=new ArrayList<Test>();

list.add(new Test(1));

list.add(new Test(3));

list.add(new Test(2));

Collections.sort(list);

System.out.println("eeeeeeeeeeeeeeeeee");

for(Test test:list){

System.out.println(test.getId());

}

}

@Override

public int compareTo(Test o) {

if (this.id > o.getId()) {

return 1;  //正序

} else {

return -1;

}

}

}