18. Spring_외부데이터 출력(.csv/json/)

1. 공공데이터 출력 (.csv)

package com.example.Ex02.TEST;

import java.io.*;

public class Ex01 {
    public static void main(String[] args) {
        File file =new File("file\\기상청27_관광코스별_관광지_지점정보.csv");
        BufferedReader br;
        String line;
        int count =0;
        try {
            br = new BufferedReader(new FileReader(file)); //연결 다리
            while((line = br.readLine()) != null) {
                count++;
                String [] arr = line.split(",");

                // 남해, 힐링 관광지 출력
                if (arr[4].contains("(남해)") && arr[10].contains("힐링")){
                    System.out.println(line);
                }
            }
            System.out.println("Count :" + count);
        } catch (FileNotFoundException e) {
            throw new RuntimeException(e);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

package com.example.Ex02.TEST;

import java.io.*;

public class Ex02 {
    public static void main(String[] args) {

        // 강남구 도서관 출력
        File file =new File("file\\서울시 공공도서관 현황정보.csv");
        BufferedReader br;
        String line;

        try {
            br = new BufferedReader(new FileReader(file));
            while((line = br.readLine()) != null){
                String[]arr = line.split(",");
                if(arr[3].equals("\"강남구\"")){
                    System.out.println(line);
                }
            }

            br.close();
            br = new BufferedReader(new FileReader(file));

            // 어린이가 포함된 도서관 출력
            int count=0;
            while((line = br.readLine()) != null){
                String[]arr = line.split(",");
                if (arr[1].contains("어린이")) {
                    count++;
                    System.out.println(line);
                }
            }
            System.out.println("총 어린이 도서관 개수: " + count);
        } catch (FileNotFoundException e) {
            throw new RuntimeException(e);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

 

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2. 공공데이터 출력 ( json) 

 

pom.xml 입력

<dependency>
            <groupId>com.googlecode.json-simple</groupId>
            <artifactId>json-simple</artifactId>
            <version>1.1</version>
</dependency>

 

 

 

현재 위치 출력

public class Ex03 {
    public static void main(String[] args) throws IOException, ParseException, JSONException {

        Path currentPath = Paths.get("."); // 현재 위치
        String path = currentPath.toAbsolutePath().toString();
        System.out.println("path : " + path); // path : C:\Spring_study\Ex16\.

 

 

test1.json

{
"name" : "apple",    
"id" : 1,    
"price" : 1000
}

        System.out.println("=========Ex01=========");
        JSONParser parser = new JSONParser(); // Json (parser)파서기를 이용해 속성과 값을 분리
        Reader reader = new FileReader("file\\test1.json");
        JSONObject jsonObject = (JSONObject)parser.parse(reader);

        String name = (String) jsonObject.get("name");
        long id = (Long) jsonObject.get("id");
        long price = (Long) jsonObject.get("price");

        System.out.println("name :" + name);
        System.out.println("id :" + id);
        System.out.println("price :" + price);

        Set keySet = jsonObject.keySet();
        for (Object key : keySet) {
            System.out.println("key: " + key + ", value: " + jsonObject.get(key));
        }
}

 

test2.json

[
	{"name":"길동","age":"44"}, 
	{"name":"상철","age":"33"}
]

  System.out.println("=========Ex02=========");
        JSONParser parser2 = new JSONParser();
        Reader reader2 = new FileReader("file\\test2.json");
        Object jsonObject2 = parser2.parse(reader2);

        JSONArray jsonArr2 = (JSONArray) jsonObject2;
        System.out.println(jsonArr2.size());

        for (int i = 0; i < jsonArr2.size(); i++) {
            JSONObject jObject = (JSONObject)jsonArr2.get(i);
            Set keySet2 = jObject.keySet();
            for (Object key : keySet2) {
                System.out.println(key + " : " + jObject.get(key));
            }
        }

 

test3.json

{
	"id" : 1,
	"employee" : [
				{"name" : "윤아", "age":30 },
				{"name" : "웬디", "age":50 }
			],
	"company" :"메타 빌드"
}

System.out.println("=========Ex03=========");
        JSONParser parser3 = new JSONParser();
        Reader reader3 = new FileReader("file\\test3.json");
        JSONObject jsonObject3 = (JSONObject)parser3.parse(reader3);

        JSONArray jsonArr3  = (JSONArray)jsonObject3.get("employee");
        for (int i = 0; i < jsonArr3.size(); i++){
            JSONObject jObject3 = (JSONObject)jsonArr3.get(i);
            Set keySet3 = jObject3.keySet();
            for (Object key : keySet3){
                System.out.println(key +":"+jObject3.get(key));
            }

        }

 

💡 요약 한 줄

Ex01 = {} 단일 객체
Ex02 = [] 여러 객체 배열
Ex03 = { "키": [ ... ] } 객체 내부 배열

 

파일명	JSON 구조	파싱 객체	접근 방법
test1.json	{} 단일 객체	JSONObject	.get("키")
test2.json	[] 배열	JSONArray	for + get(i)
test3.json	{ "employee": [ ... ] }	JSONObject → JSONArray	get("employee") 후 반복

 

전체코드

package com.example.Ex02.TEST;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Set;

public class Ex03 {
    public static void main(String[] args) throws IOException, ParseException {

        // 현재 실행 경로 출력
        Path currentPath = Paths.get(".");
        String path = currentPath.toAbsolutePath().toString();
        System.out.println("path : " + path);

        // ------------------ Ex01: 단일 객체 ------------------
        System.out.println("=========Ex01=========");
        JSONParser parser = new JSONParser();
        Reader reader = new FileReader("file\\test1.json");
        JSONObject jsonObject = (JSONObject) parser.parse(reader);

        // 개별 key-value 접근
        System.out.println("name : " + jsonObject.get("name"));
        System.out.println("id : " + jsonObject.get("id"));
        System.out.println("price : " + jsonObject.get("price"));

        // 전체 key-value 출력
        for (Object key : jsonObject.keySet())
            System.out.println(key + " : " + jsonObject.get(key));


        // ------------------ Ex02: 배열 ------------------
        System.out.println("=========Ex02=========");
        JSONParser parser2 = new JSONParser();
        Reader reader2 = new FileReader("file\\test2.json");
        JSONArray jsonArr2 = (JSONArray) parser2.parse(reader2);

        // 배열 안의 각 객체 출력
        for (Object obj : jsonArr2) {
            JSONObject jObject = (JSONObject) obj;
            for (Object key : jObject.keySet())
                System.out.println(key + " : " + jObject.get(key));
        }


        // ------------------ Ex03: 객체 내부 배열 ------------------
        System.out.println("=========Ex03=========");
        JSONParser parser3 = new JSONParser();
        Reader reader3 = new FileReader("file\\test3.json");
        JSONObject jsonObject3 = (JSONObject) parser3.parse(reader3);

        // "employee" 배열 추출 후 반복 출력
        JSONArray jsonArr3 = (JSONArray) jsonObject3.get("employee");
        for (Object obj : jsonArr3) {
            JSONObject jObject3 = (JSONObject) obj;
            for (Object key : jObject3.keySet())
                System.out.println(key + " : " + jObject3.get(key));
        }
    }
}

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3. 공공데이터 출력 ( json)