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JAVA

230110_Stream

by 경 훈 2023. 1. 10.

스트림(Stream) = 또 다른 처리방식의 하나

객체명.stream().중간함수.중간함수.최종함수

중간함수

값을 불러오는 mapToInt  : 정수를 불러옴

                      mapToDouble : 실수를 불러옴

조건설정(if~)  filter.

정열 (sorted).Compartor...

 

package day27_1;

public class DTO {
	String spname;
	int su;
	int dan;
	int price;
	public DTO() {}
	public DTO(String spname, int su, int dan, int price) {
		super();
		this.spname = spname;
		this.su = su;
		this.dan = dan;
		this.price = price;
	}
	public String getSpname() {
		return spname;
	}
	public void setSpname(String spname) {
		this.spname = spname;
	}
	public int getSu() {
		return su;
	}
	public void setSu(int su) {
		this.su = su;
	}
	public int getDan() {
		return dan;
	}
	public void setDan(int dan) {
		this.dan = dan;
	}
	public int getPrice() {
		return price;
	}
	public void setPrice(int price) {
		this.price = price;
	}
	@Override
	public String toString() {
		return "DTO [spname=" + spname + ", su=" + su + ", dan=" + dan + ", price=" + price + "]";
	}
}

 

package day27_1;

import java.io.FileNotFoundException;
import java.util.Scanner;

public class Menu {

	public static void main(String[] args) throws FileNotFoundException {
		Scanner sc = new Scanner(System.in);
		DAO dao = new DAO();
		while(true) {
			System.out.println("[0]종료\t[1]입력\t[2]출력\t[3]자료건수");
			System.out.println("[4]금액이 10만이상 자료건수");
			System.out.println("[5]금액이 10만이상 목록");
			System.out.println("[6]입력상품명 리스트");
			System.out.print("원하시는 작업번호");
			int n = sc.nextInt();
			switch (n) {
			case 0:System.exit(0);break;
			case 1:dao.insert();break;
			case 2:dao.out();break;
			case 3:dao.count();break;
			case 4:dao.forcount();break;
			case 5:dao.onotherlist();break;
			case 6:dao.spnamelist();break;
			}
		}
	}
}

 

package day27_1;

public class Process {
	public int tot (int su,int dan) {
		return su*dan;
	}
}

 

package day27_1;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Collectors;

public class DAO {
	enum ss {a("사과군"),b("바나나"),o("오렌지"),m("망고군");
		private String value;
		private ss(String value) {
			this.value = value;
		}
		public String getValue() {
			return value;
		}
	}
	ArrayList<DTO> list = new ArrayList<DTO>();
	public void insert() throws FileNotFoundException {
		FileReader fr = new FileReader("c:/data/01101.txt");
		BufferedReader br= new BufferedReader(fr);
		Process pr = new Process();
		while(true) {
			try {
				String str = br.readLine();
				if(str==null)break;
				String name = ss.valueOf(str.substring(0, 1)).getValue();
				int su = Integer.parseInt(str.substring(1, 3));
				int dan = Integer.parseInt(str.substring(3, 7));	
				int price = pr.tot(su, dan);
				list.add(new DTO(name, su, dan, price));
				
//				//세터 입력방식
//				DTO dto = new DTO();
//				dto.setSpname(ss.valueOf(str.substring(0, 1)).getValue());
//				dto.setSu(Integer.parseInt(str.substring(1, 3)));
//				dto.setDan(Integer.parseInt(str.substring(3, 7)));
//				dto.setPrice(pr.tot(dto.getSu(), dto.getDan()));
//				list.add(dto);
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
	public void out() {
		System.out.println("==람다식출력==");
		list.forEach(s->System.out.println(s.toString()));
		System.out.println("==빠른 for==");
		for(DTO s:list) {
			System.out.println(s.toString());
		}
	}
	//count 기능 .. 전체 자료의 건수
	public void count() {
		long su = list.stream().count(); // 자료의 갯수
		System.out.println("자료의 건수 : "+su+"건");
	}
	//금액이 10만 이상인것을 찾아냄
	public void forcount() {
		long ks1 = list.stream().filter(s->s.getPrice()>=100000).count();
		System.out.println("10만 이상의 자료의 건수 : "+ks1+"건");
	}
	public void forcount2() {
		long ks2 = list.stream().filter(s->s.getDan()>=2000).count();
		System.out.println("단가가 2000원 이상의 건수 : "+ks2+"건");
	}
	public void onotherlist() {
		List<DTO> newlist = list.stream().filter(s->s.getPrice()>=100000).collect(Collectors.toList());
		newlist.forEach(s->System.out.println(s.toString()));
	}
	public void spnamelist() {
		System.out.println("상품명을 입력하시오");
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
		List<DTO> splist = list.stream().filter(s->s.getSpname().equals(str)).collect(Collectors.toList());
		splist.forEach(s->System.out.println(s.toString()));
	}
}
package day27_1;

import java.io.FileNotFoundException;
import java.util.Scanner;

public class Menu {

	public static void main(String[] args) throws FileNotFoundException {
		Scanner sc = new Scanner(System.in);
		DAO dao = new DAO();
		while(true) {
			System.out.println("[0]종료\t[1]입력\t[2]출력");
			System.out.println("[3]수량,단가,금액의 합");
			System.out.println("[4]수량,단가,금액의 평균");
			System.out.print("원하시는 작업번호");
			int n = sc.nextInt();
			switch (n) {
			case 0:System.exit(0);break;
			case 1:dao.insert();break;
			case 2:dao.out();break;
			case 3:dao.suhap();break;
			case 4:dao.suavg();break;
			}
		}
	}
}

 

package day27_1;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Collectors;

public class DAO {
	enum ss {a("사과군"),b("바나나"),o("오렌지"),m("망고군");
		private String value;
		private ss(String value) {
			this.value = value;
		}
		public String getValue() {
			return value;
		}
	}
	ArrayList<DTO> list = new ArrayList<DTO>();
	DecimalFormat df = new DecimalFormat("#,##0.0");
	public void insert() throws FileNotFoundException {
		FileReader fr = new FileReader("c:/data/01101.txt");
		BufferedReader br= new BufferedReader(fr);
		Process pr = new Process();
		while(true) {
			try {
				String str = br.readLine();
				if(str==null)break;
				String name = ss.valueOf(str.substring(0, 1)).getValue();
				int su = Integer.parseInt(str.substring(1, 3));
				int dan = Integer.parseInt(str.substring(3, 7));	
				int price = pr.tot(su, dan);
				list.add(new DTO(name, su, dan, price));
				
//				//세터 입력방식
//				DTO dto = new DTO();
//				dto.setSpname(ss.valueOf(str.substring(0, 1)).getValue());
//				dto.setSu(Integer.parseInt(str.substring(1, 3)));
//				dto.setDan(Integer.parseInt(str.substring(3, 7)));
//				dto.setPrice(pr.tot(dto.getSu(), dto.getDan()));
//				list.add(dto);
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
	public void out() {
		System.out.println("==람다식출력==");
		list.forEach(s->System.out.println(s.toString()));
	}
	//수량의 합
	public void suhap() {
		int suhap = list.stream().mapToInt(DTO::getSu).sum();
		int danhap = list.stream().mapToInt(DTO::getDan).sum();
		int prhap = list.stream().mapToInt(DTO::getPrice).sum();
		System.out.println("수량의 합 : "+suhap);
		System.out.println("단가의 합 : "+danhap);
		System.out.println("금액의 합 : "+prhap);
	}
	public void suavg() {
		double suavg = list.stream().mapToInt(DTO::getSu).average().getAsDouble();
		double danavg = list.stream().mapToInt(DTO::getDan).average().getAsDouble();
		double pravg = list.stream().mapToInt(DTO::getPrice).average().getAsDouble();
		System.out.println("수량의 평균 : "+df.format(suavg));
		System.out.println("단가의 평균 : "+df.format(danavg));
		System.out.println("금액의 평균 : "+df.format(pravg));
	}
}
package day27_1;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeMap;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class DAO {
	enum ss {a("사과군"),b("바나나"),o("오렌지"),m("망고군");
		private String value;
		private ss(String value) {
			this.value = value;
		}
		public String getValue() {
			return value;
		}
	}
	ArrayList<DTO> list = new ArrayList<DTO>();
	DecimalFormat df = new DecimalFormat("#,##0.0");
	public void insert() throws FileNotFoundException {
		FileReader fr = new FileReader("c:/data/01101.txt");
		BufferedReader br= new BufferedReader(fr);
		Process pr = new Process();
		while(true) {
			try {
				String str = br.readLine();
				if(str==null)break;
				String name = ss.valueOf(str.substring(0, 1)).getValue();
				int su = Integer.parseInt(str.substring(1, 3));
				int dan = Integer.parseInt(str.substring(3, 7));	
				int price = pr.tot(su, dan);
				list.add(new DTO(name, su, dan, price));
				
//				//세터 입력방식
//				DTO dto = new DTO();
//				dto.setSpname(ss.valueOf(str.substring(0, 1)).getValue());
//				dto.setSu(Integer.parseInt(str.substring(1, 3)));
//				dto.setDan(Integer.parseInt(str.substring(3, 7)));
//				dto.setPrice(pr.tot(dto.getSu(), dto.getDan()));
//				list.add(dto);
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
	public void out() {
		System.out.println("==람다식출력==");
		list.forEach(s->System.out.println(s.toString()));
	}
	//수량의 합
	public void suhap(Scanner sc) {
		System.out.print("원하는 상품명을 입력하시오");
		String sname = sc.next();
		int suhap = list.stream().filter(s->s.getSpname().equals(sname)).mapToInt(DTO::getSu).sum();
		int danhap = list.stream().filter(s->s.getSpname().equals(sname)).mapToInt(DTO::getDan).sum();
		int prhap = list.stream().filter(s->s.getSpname().equals(sname)).mapToInt(DTO::getPrice).sum();
		System.out.println("수량의 합 : "+suhap);
		System.out.println("단가의 합 : "+danhap);
		System.out.println("금액의 합 : "+prhap);
	}
	public void suavg() {
		double suavg = list.stream().mapToInt(DTO::getSu).average().getAsDouble();
		double danavg = list.stream().mapToInt(DTO::getDan).average().getAsDouble();
		double pravg = list.stream().mapToInt(DTO::getPrice).average().getAsDouble();
		System.out.println("수량의 평균 : "+df.format(suavg));
		System.out.println("단가의 평균 : "+df.format(danavg));
		System.out.println("금액의 평균 : "+df.format(pravg));
	}
	//전체상품에 대한 금액의 합
	public void totalhap() {
		TreeMap<String, Integer> map = new TreeMap<String, Integer>();
		for(int i=0;i<list.size();i++) {
			map.put(list.get(i).getSpname(), list.get(i).getPrice());
		}
		//map구조에서 정의 .. 문자열(키)과 값중에서 키값만 모음
		Set<String> kset = map.keySet(); //상품명 4가지만..
		//키값들은 세트로 구성--> 낱개로 분리
		Iterator<String> it = kset.iterator();//위의 세트에서 낱개로 구분
		while(it.hasNext()) {
			String spname = it.next();
			int hap = list.stream().filter(s->s.getSpname().equals(spname)).mapToInt(DTO::getPrice).sum();
			System.out.println(spname+"의 총금액은 : "+hap);
		}
	}
	//이름을 오름차순으로 정렬
	public void spnameAscSort() {
		List<DTO> sortlist = list.stream().sorted(Comparator.comparing(DTO::getSpname)).collect(Collectors.toList());
		System.out.println("상품명 오름차순 출력");
		sortlist.forEach(s->System.out.println(s.toString()));
	}
	//이름을 내림차순으로 정렬
	public void spnamedescSort() {
		List<DTO> desclist = list.stream().sorted(Comparator.comparing(DTO::getSpname).reversed()).collect(Collectors.toList());
		System.out.println("상품명 내림차순 출력");
		desclist.forEach(s->System.out.println(s.toString()));
	}
	//상품명으로 오름..금액 오름차순 정렬
	public void ascasc() {
//		Stream<DTO> ascasc2 = list.stream().sorted(Comparator.comparing(DTO::getSpname).thenComparing(Comparator.comparing(DTO::getPrice)));
//		ascasc2.forEach(s->System.out.println(s.toString()));
		List<DTO> ascasc = list.stream().sorted(Comparator.comparing(DTO::getSpname).thenComparing(Comparator.comparing(DTO::getPrice))).collect(Collectors.toList());
		ascasc.forEach(s->System.out.println(s.toString()));
	}
	//상품명은 오름..금액은 내림차순 정렬
	public void ascdesc() {
//		Stream<DTO> ascdesc2 = list.stream().sorted(Comparator.comparing(DTO::getSpname).thenComparing(Comparator.comparing(DTO::getPrice).reversed()));
//		ascdesc2.forEach(s->System.out.println(s.toString()));
		List<DTO> ascdesc = list.stream().sorted(Comparator.comparing(DTO::getSpname).thenComparing(Comparator.comparing(DTO::getPrice).reversed())).collect(Collectors.toList());
		ascdesc.forEach(s->System.out.println(s.toString()));
	}
	//상품명은 내림..금액은 오름차순 정렬
	public void descasc() {
		List<DTO> descasc = list.stream().sorted(Comparator.comparing(DTO::getSpname).reversed().thenComparing(DTO::getPrice)).collect(Collectors.toList());
		descasc.forEach(s->System.out.println(s.toString()));
	}
	//상품명은 내림..금액은 내림차순 정렬
	public void descdesc() {
		List<DTO> descdesc = list.stream().sorted(Comparator.comparing(DTO::getSpname).reversed().thenComparing(Comparator.comparing(DTO::getPrice).reversed())).collect(Collectors.toList());
		descdesc.forEach(s->System.out.println(s.toString()));
	}
	//Map구조와 클래스 연결..
	public void mapclass(Scanner sc) {
		System.out.println("상품명을 입력하시오");
		String name = sc.next();
		Map<String, List<DTO>> mapa = list.stream().collect(Collectors.groupingBy(DTO::getSpname));
		mapa.get(name).forEach(s->System.out.println(s.toString()));
	}
	//전체상품명에 대한 DTO출력
	public void maptot() {
		Map<String, List<DTO>> mapa = list.stream().collect(Collectors.groupingBy(DTO::getSpname));
		Set<String> kset = mapa.keySet();
		Iterator<String> it = kset.iterator();
		while(it.hasNext()) {
			String name = it.next();
			mapa.get(name).forEach(s->System.out.println(s.toString()));
		}
	}
	//각 상품명에 대한 건수
	public void namecount() {
		Map<String, List<DTO>> mapa = list.stream().collect(Collectors.groupingBy(DTO::getSpname));
		Set<String> kset = mapa.keySet();
		Iterator<String> it = kset.iterator();
		while(it.hasNext()) {
			String name = it.next();
			long su = list.stream().filter(s->s.getSpname().equals(name)).count();
			System.out.println(name+"의 건수 : "+su+"건");
		}
	}
}

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