Java实现类排序-优快云博客

用Java实现类排序如下步骤：

1 待排序的类实现 Comparable 接口

2 重写compareTo 方法

3 Collections.sort(listStu); 实现排序

代码如下：

public class Student implements {

private int id;
private String name;

public int getId() {
  return id;
}

public void setId(int id) {
  this.id = id;
}

public String getName() {
  return name;
}

public void setName(String name) {
  this.name = name;
}

    public int compareTo(Object arg0) {
  Student student1 = (Student) arg0;
  // 按名字排序27
  if(student1.id>this.id){
   return -1;
  }else if(student1.id<this.id){
   return 1;
  }else{
   return 0;
  }
}

    public String toString(){
    String reStr = "";
    reStr += "id=" + id + " ";
    reStr += "name=" + name + " ";
    return reStr;
    }

}

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class TestClass {

public static void main(String[] args){

  List listStu = new ArrayList();

  Student stu0 = new Student();
  stu0.setId(32);
  listStu.add(stu0);

  Student stu1 = new Student();
  stu1.setId(12);
  listStu.add(stu1);

  Student stu2 = new Student();
  stu2.setId(52);
  listStu.add(stu2);

  Student stu3 = new Student();
  stu3.setId(65);
  listStu.add(stu3);

  Student stu4 = new Student();
  stu4.setId(21);
  listStu.add(stu4);

  Student stu5 = new Student();
  stu5.setId(35);
  listStu.add(stu5);

  Student stu6 = new Student();
  stu6.setId(123);
  listStu.add(stu6);

  Student stu7 = new Student();
  stu7.setId(78);
  listStu.add(stu7);

  Student stu8 = new Student();
  stu8.setId(96);
  listStu.add(stu8);

  Student stu9 = new Student();
  stu9.setId(75);
  listStu.add(stu9);

  Collections.sort(listStu);
  printList(listStu);
}

public static void printList(List list){

  if(list == null || list.size()==0){
   System.out.println("list is null");
  }
  for(int i=0; i<list.size(); i++){
   System.out.println(list.get(i));
  }
}

}