对ArrayList集合中的元素进行排序_arraylist排序

如果要对ArrayList集合中的元素进行排序，需要用到java工具包中的Collections类的sort方法。

具体用法可以查看jdk帮助文档。

在这里先创建一个Person类，包含姓名，性别，年龄，身份证号，出生日期。如以下代码：

public class Person {
  private String name;
  private String birthday;
  private String idCard;
  private char sex;
  private int age;

  //getters和setters
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public String getBirthday() {
    return birthday;
  }
  public void setBirthday(String birthday) {
    this.birthday = birthday;
  }
  public String getIdCard() {
    return idCard;
  }
  public void setIdCard(String idCard) {
    this.idCard = idCard;
  }
  public char getSex() {
    return sex;
  }
  public void setSex(char sex) {
    this.sex = sex;
  }
  public int getAge() {
    return age;
  }
  public void setAge(int age) {
    this.age = age;
  }
  //构造函数
  public Person(){}
  public Person(String name,String birthday,String idCard,char sex,int age){
    this.name = name;
    this.birthday = birthday;
    this.idCard = idCard;
    this.sex = sex;
    this.age = age;
  }
  //输出信息
  public String toString(){
    return name+","+sex+","+age+","+birthday+","+idCard;
  }
}
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然后创建排序的类（其中包括按照姓名排序，按照年龄排序，按照出生日期排序），如以下代码所示：

import java.util.Comparator;
public class CompareName implements Comparator<Person>{
  //按照姓名进行排序
  @Override
  public int compare(Person p1, Person p2) {
    // TODO Auto-generated method stub
    return p1.getName().compareTo(p2.getName());
  }
}
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class CompareBirthday implements Comparator<Person>{
  //按照出生日期进行排序
  @Override
  public int compare(Person p1, Person p2) {
    // TODO Auto-generated method stub
    return p1.getBirthday().compareTo(p2.getBirthday());
  }
}
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class CompareAge implements Comparator<Person>{
  //按照年龄进行排序
  @Override
  public int compare(Person p1, Person p2) {
      // TODO Auto-generated method stub
      if(p1.getAge()>p2.getAge())
          return 1;
      else return -1;
  }
}
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最后创建一个主类（在这里我明明为First），用来调用以上所写的类并使程序可以执行。

import java.util.ArrayList;
import java.util.Collections;
public class First {
  public static void main(String[] args){
      ArrayList<Person> value = new ArrayList<Person>();
      Person p1 = new Person("张三","1994-3-3","45612346548",'男',26);
      Person p2 = new Person("赵四","2000-5-24","16546165746",'男',20);
      Person p3 = new Person("刘武","1997-2-3","156461656487",'男',23);
      Person p4 = new Person("丁晓晓","1996-6-13","36548588788",'女',24);
      //将创建的各元素添加到ArrayList集合中
      value.add(p1);
      value.add(p2);
      value.add(p3);
      value.add(p4);
      CompareName cn = new CompareName();
      CompareBirthday cb = new CompareBirthday();
      CompareAge ca = new CompareAge();
      System.out.println("\n按姓名排序：");//其中\n表示换行
      Collections.sort(value,cn);
      for(int i = 0; i < value.size(); i++)
          System.out.println(value.get(i).toString());
      System.out.println("\n按年龄排序：");
      Collections.sort(value,ca);
      for(int i = 0; i < value.size(); i++)
          System.out.println(value.get(i).toString());
      System.out.println("\n按生日排序：");
      Collections.sort(value,cb);
      for(int i = 0; i < value.size(); i++)
          System.out.println(value.get(i).toString());
  }
}
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最后看一下运行结果：
按姓名排序：
丁晓晓,女,24,1996-6-13,36548588788
刘武,男,23,1997-2-3,156461656487
张三,男,26,1994-3-3,45612346548
赵四,男,20,2000-5-24,16546165746

按年龄排序：
赵四,男,20,2000-5-24,16546165746
刘武,男,23,1997-2-3,156461656487
丁晓晓,女,24,1996-6-13,36548588788
张三,男,26,1994-3-3,45612346548

按生日排序：
张三,男,26,1994-3-3,45612346548
丁晓晓,女,24,1996-6-13,36548588788
刘武,男,23,1997-2-3,156461656487
赵四,男,20,2000-5-24,16546165746