Ex)T04ListSortTest Comparable , Comparator 차이

1. 전체값 출력 

package kr.or.ddit.basic;

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

public class T04ListSortTest {
	public static void main(String[] args) {
		
		List<Member> memList = new ArrayList<Member>();
		
		memList.add(new Member(1, "홍길동" , "010-1111-1111"));
		memList.add(new Member(5, "변학도" , "010-2222-1111"));
		memList.add(new Member(9, "성춘향" , "010-3333-1111"));
		memList.add(new Member(3, "이순신" , "010-4444-1111"));
		memList.add(new Member(6, "강감챤" , "010-5555-1111"));
		memList.add(new Member(2, "일지매" , "010-6666-1111"));
		
		System.out.println("정렬 전 : ");
		for(Member m : memList) {
			System.out.println(m);
		}
		System.out.println("-----------------------------");
		
		Collections.sort(memList);	//정렬하기
		
		System.out.println("회원이름 오름차순 정렬 정렬 후 : ");
		for(Member m : memList) {
			System.out.println(m);
		}
		
		Collections.shuffle(memList); //회원정보 섞기 
		
		System.out.println("섞은후 : ");
		for(Member m : memList) {
			System.out.println(m);
		}
		
		Collections.sort(memList,new SortNumDesc());
		
		System.out.println("회운번호 내림차순 정렬 후 : ");
		for(Member m : memList) {
			System.out.println(m);
		}
	}
}
// 회원 번호의 내림차순으로 정렬되도록 외부 정렬자 클래스 구현 
class SortNumDesc implements Comparator<Member>{
//Comparable ?
//Comparator ?
	
	@Override
	public int compare(Member mem1 , Member mem2) {
//		
//		if(mem1.getNum() > mem2.getNum()) {
//			return -1;
//		}else if(mem1.getNum() == mem2.getNum()){
//			return 0;
//		}else {
//			return 1;
//		}						정석방법
	//	return new Integer(mem1.getNum()).compareTo(mem2.getNum());//오름차순 정렬		//첫번쨰 회원번호 이용해서 Integer 객체를 만듬  
	//  return new Integer(mem1.getNum()).compareTo(mem2.getNum()) * -1;	//내림차순 정렬 
		return Integer.compare(mem1.getNum(), mem2.getNum()) * -1;
	}
	
}

// 회원이름을 기준으로 오름차순 정렬이 되도록 구현하기
class Member implements Comparable<Member>{
	private int num;		//번호
	private String name;	//이름
	private String tel;		//전화번호

	public Member(int num, String name, String tel) {
		super();
		this.num = num;
		this.name = name;
		this.tel = tel;
	}
	public int getNum() {
		return num;
	}
	public void setNum(int num) {
		this.num = num;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getTel() {
		return tel;
	}
	public void setTel(String tel) {
		this.tel = tel;
	}
	@Override
	public String toString() {
		return "Member [num=" + num + ", name=" + name + ", tel=" + tel + "]";
	}
	@Override
	public int compareTo(Member mem) {
		
		
		
		return this.getName().compareTo(mem.getName());
	}
		
}

 

[2] 구문 분석 

public class T04ListSortTest {
	public static void main(String[] args) {
		
		List<Member> memList = new ArrayList<Member>();
		//기본값 출력 
		memList.add(new Member(1, "홍길동" , "010-1111-1111"));
		memList.add(new Member(5, "변학도" , "010-2222-1111"));
		memList.add(new Member(9, "성춘향" , "010-3333-1111"));
		memList.add(new Member(3, "이순신" , "010-4444-1111"));
		memList.add(new Member(6, "강감챤" , "010-5555-1111"));
		memList.add(new Member(2, "일지매" , "010-6666-1111"));
		
		System.out.println("정렬 전 : ");
		for(Member m : memList) {
			System.out.println(m);
		}

// 회원이름을 기준으로 오름차순 정렬이 되도록 구현하기
class Member implements Comparable<Member>{
	private int num;		//번호
	private String name;	//이름
	private String tel;		//전화번호

	public Member(int num, String name, String tel) {
		super();
		this.num = num;
		this.name = name;
		this.tel = tel;
	}
	public int getNum() {
		return num;
	}
	public void setNum(int num) {
		this.num = num;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getTel() {
		return tel;
	}
	public void setTel(String tel) {
		this.tel = tel;
	}
	@Override
	public String toString() {
		return "Member [num=" + num + ", name=" + name + ", tel=" + tel + "]";
	}
	@Override
	public int compareTo(Member mem) {
	
		return this.getName().compareTo(mem.getName());
	}
		
}

결과값 

2.