json 파싱하기

의존성

dependencies {
    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.1'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.1'
    implementation group: 'com.googlecode.json-simple', name: 'json-simple', version: '1.1'
    compileOnly 'org.projectlombok:lombok:1.16.20'
    implementation 'com.google.code.gson:gson:2.8.7'

    // https://mvnrepository.com/artifact/org.json/json
    implementation group: 'org.json', name: 'json', version: '20210307'

}

package javaAPI.test0;

import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;
import javaAPI.gitTest.JavaJjangPostHandler;

import java.io.IOException;
import java.net.InetSocketAddress;

public class JavaServer {

    private Integer port = 5678;
    private HttpServer server = null;
    public JavaServer() throws IOException {

        server = HttpServer.create(new InetSocketAddress(port), 0);
        server.createContext("/", new MyHandler());
        server.createContext("/sum", new MyHandler3());
        server.createContext("/user", new MyHandler4());
        server.setExecutor(null);
        server.start();
        System.out.println("server started on port " + port);
    }


}

Main

package javaAPI.test0;

import com.sun.net.httpserver.HttpServer;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.List;

public class Main {

    public static void main(String[] args) throws IOException {


        JavaServer server = new JavaServer();

        /*
        int port = 5678;
        HttpServer server = HttpServer.create(new InetSocketAddress(port), 0);
        server.createContext("/", new MyHandler());
        server.setExecutor(null);
        server.start();
        System.out.println("server started on port " + port);

         */


    }
}

package javaAPI.test0;

import com.google.gson.Gson;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;

import java.io.IOException;
import java.io.OutputStream;
import org.json.simple.JSONObject;


/**
 * 요구사항 1.
 * 클라이언트가  "/" , "content-type, json " 요청을 보낼때
 * API 서버를 하나 5678포트로 생성해서
 * json 형태로  "message" : "server check" 를 담아주는 요구사항
 */
public class MyHandler implements HttpHandler {
    @Override
    public void handle(HttpExchange exchange) throws IOException {

        Gson gson = new Gson();
        String response = "";
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("message", "server check");
        exchange.getResponseHeaders().add("Content-Type", "application/json"); // 응답 헤더 설정
        exchange.sendResponseHeaders(200, response.getBytes().length); // 응답 코드와 길이 설정

        // jsonObject을 json 문자열로 변환
        String jsonStr = gson.toJson(jsonObject);

        // 생성된 json 문자열 출력
        System.out.println(jsonStr);

        OutputStream os = exchange.getResponseBody();
        os.write(jsonStr.getBytes());
        os.close();



    }
}

package javaAPI.test0;

import com.google.gson.Gson;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.gson.stream.JsonReader;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import org.json.simple.JSONArray;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Map;
import java.util.Set;


/**
 * 이미 있는  JSON 파일  파싱하기
 */
public class MyHandler2 implements HttpHandler {

    @Override
    public void handle(HttpExchange exchange) throws IOException {
        System.out.println("MyHandler2 call..");

        Gson gson = new Gson();


        // FileReader 생성

        String path = MyHandler2.class.getResource("").getPath();
        System.out.println("path :" + path);



/*
        // json파일 읽어서, User 객체로 변환

        System.out.println("성공?");
        Gson gson = new Gson();
        User user = gson.fromJson(fileReader, User.class);

        // User 객체 출력 및 post_count의 총합 구하기
        System.out.println(user);

 */

        //
        String filePath = "/Users/gimhwigyeong/Desktop/hwi/project/javaAPI/src/main/java/javaAPI/test0/user.json";
        try {
            JsonReader jsonReader = new JsonReader(new FileReader(filePath));
            JsonObject object = gson.fromJson(jsonReader, JsonObject.class);
            System.out.println("\"user_id\" : " + object.get("user_id"));
            //System.out.println(object.toString());

            System.out.println("중간 ===");

            Set<Map.Entry<String, JsonElement>> element = object.entrySet();

            for(Map.Entry<String, JsonElement> entry : element){
                System.out.println("key: " + entry.getKey());
                System.out.println("val: " + entry.getValue());
                System.out.println("==========================");
            }



        }catch (Exception e){
            System.out.println("error");
            e.printStackTrace();
        }











    }
}

package javaAPI.test0;

import com.google.gson.Gson;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.stream.JsonReader;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import org.json.simple.JSONArray;

import java.io.FileReader;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import java.util.Set;


/**
 * 요구사항3
 * 이미 있는  JSON 파일  파싱하기2
 * - 모든 user의 post_count의 합
 */
public class MyHandler3 implements HttpHandler {

    @Override
    public void handle(HttpExchange exchange) throws IOException {
        System.out.println("MyHandler2 call..");

        Gson gson = new Gson();


        // FileReader 생성

        String path = MyHandler3.class.getResource("").getPath();
        System.out.println("path :" + path);



/*
        // json파일 읽어서, User 객체로 변환

        System.out.println("성공?");
        Gson gson = new Gson();
        User user = gson.fromJson(fileReader, User.class);

        // User 객체 출력 및 post_count의 총합 구하기
        System.out.println(user);

 */

        //
        String filePath = "/Users/gimhwigyeong/Desktop/hwi/project/javaAPI/src/main/java/javaAPI/data/user2.json";

        String jsonStr = "";
        try {

            JsonReader jsonReader = new JsonReader(new FileReader(filePath));

            JSONArray jsonArray = gson.fromJson(jsonReader, JSONArray.class);

            System.out.println(jsonArray.toString());
            System.out.println("size: " + jsonArray.size());
            System.out.println("get0: " + jsonArray.get(0));


            int sum = 0;
            for(int i = 0; i < jsonArray.size(); i++){
                JsonObject object = gson.fromJson(jsonArray.get(i).toString(), JsonObject.class);
                String user_id = object.get("user_id").getAsString();
                String username = object.get("username").getAsString();
                String count = object.get("post_count").getAsString();
                /*
                System.out.println("user_id: " + user_id);
                System.out.println("username: " + username);
                System.out.println("post_count: " + count);

                 */

                int post_count = object.get("post_count").getAsInt();
                sum += post_count;
            }

            System.out.println("모든 user의 post_count의 합: " + sum);

            JsonObject resultObject = new JsonObject();
            resultObject.addProperty("sum", sum);
            jsonStr = gson.toJson(resultObject);

            exchange.getResponseHeaders().add("Content-Type", "application/json"); // 응답 헤더 설정
            exchange.sendResponseHeaders(200, jsonStr.getBytes().length); // 응답 코드와 길이 설정

        }catch (Exception e){
            System.out.println("error");
            exchange.getResponseHeaders().add("Content-Type", "application/json"); // 응답 헤더 설정
            exchange.sendResponseHeaders(500, jsonStr.getBytes().length); // 응답 코드와 길이 설정
            e.printStackTrace();
        }finally {
            OutputStream os = exchange.getResponseBody();
            os.write(jsonStr.getBytes());
            os.close();

        }



    }
}

package javaAPI.test0;

import com.google.gson.Gson;
import com.google.gson.JsonObject;
import com.google.gson.stream.JsonReader;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import org.json.simple.JSONArray;

import java.io.FileReader;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;


/**
 * 요구사항4
 * 이미 있는  JSON 파일  파싱하기
 * - User 객체로 변환한 후, 모든 user의 post_count의 합 구하기
 */
public class MyHandler4 implements HttpHandler {

    @Override
    public void handle(HttpExchange exchange) throws IOException {
        System.out.println("MyHandler4 call..");

        Gson gson = new Gson();


/*
        // json파일 읽어서, User 객체로 변환

        System.out.println("성공?");
        Gson gson = new Gson();
        User user = gson.fromJson(fileReader, User.class);

        // User 객체 출력 및 post_count의 총합 구하기
        System.out.println(user);

 */

        //
        String filePath = "/Users/gimhwigyeong/Desktop/hwi/project/javaAPI/src/main/java/javaAPI/data/user2.json";

        String jsonStr = "";
        try {

            JsonReader jsonReader = new JsonReader(new FileReader(filePath));

            JSONArray jsonArray = gson.fromJson(jsonReader, JSONArray.class);

            System.out.println(jsonArray.toString());
            System.out.println("size: " + jsonArray.size());
            System.out.println("get0: " + jsonArray.get(0));


            int sum = 0;
            List<User> userList = new ArrayList<>();
            for(int i = 0; i < jsonArray.size(); i++){
                //JsonObject object = gson.fromJson(jsonArray.get(i).toString(), JsonObject.class);
                User users = gson.fromJson(jsonArray.get(i).toString(), User.class);


                int user_id = users.getUser_id();
                String username = users.getUsername();
                int count = users.getPost_count();
                System.out.println("user_id: " + user_id + ", username: " + username);

                userList.add(new User(user_id, username, count));


            }

            for(User user : userList){
                sum += user.getPost_count();
            }

            System.out.println("모든 user의 post_count의 합: " + sum);

            JsonObject resultObject = new JsonObject();
            resultObject.addProperty("sum", sum);
            jsonStr = gson.toJson(resultObject);

            exchange.getResponseHeaders().add("Content-Type", "application/json"); // 응답 헤더 설정
            exchange.sendResponseHeaders(200, jsonStr.getBytes().length); // 응답 코드와 길이 설정

        }catch (Exception e){
            System.out.println("error");
            exchange.getResponseHeaders().add("Content-Type", "application/json"); // 응답 헤더 설정
            exchange.sendResponseHeaders(500, jsonStr.getBytes().length); // 응답 코드와 길이 설정
            e.printStackTrace();
        }finally {
            OutputStream os = exchange.getResponseBody();
            os.write(jsonStr.getBytes());
            os.close();

        }



    }
}

package javaAPI.test0;

public class User {

    int user_id;
    String username;
    int post_count;

    public int getUser_id() {
        return user_id;
    }

    public void setUser_id(int user_id) {
        this.user_id = user_id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public int getPost_count() {
        return post_count;
    }

    public void setPost_count(int post_count) {
        this.post_count = post_count;
    }

    public User(int user_id, String username, int post_count) {
        this.user_id = user_id;
        this.username = username;
        this.post_count = post_count;
    }

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder("User{");
        sb.append("user_id=").append(user_id);
        sb.append(", username='").append(username).append('\'');
        sb.append(", post_count=").append(post_count);
        sb.append('}');
        return sb.toString();
    }
}

////추가

 

package javaAPI.gitTest;

import java.io.IOException;

public class Main {

    public static void main(String[] args) throws IOException {
        JavaJjangServer server = new JavaJjangServer();
    }
}

package javaAPI.gitTest;

import com.sun.net.httpserver.HttpServer;

import java.io.IOException;
import java.net.InetSocketAddress;

public class JavaJjangServer {
    private Integer port = 8000;
    private HttpServer server = null;
    public JavaJjangServer() throws IOException {
        System.out.println("Java JJang Server On! port : 8000");
        server = HttpServer.create(new InetSocketAddress(port), 0);
        server.createContext("/javajjang", new JavaJjangPostHandler());
        server.setExecutor(null);
        server.start();
    }
}

package javaAPI.gitTest;

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;

import java.io.*;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class JavaJjangPostHandler implements HttpHandler {

    // 요청 들어오면 Start
    @Override
    public void handle(HttpExchange exchange) throws IOException {
        System.out.println("JavaJJANG Post Handler-------");

        // json으로 입력받음
        InputStreamReader isr = new InputStreamReader(exchange.getRequestBody(), "utf-8");
        BufferedReader br = new BufferedReader(isr);

        String query = br.readLine();
        System.out.println("쿼리 : \"" + query + "\"");

        Integer seed = getSeedFromQuery(query);
        System.out.println(seed);

        RandomMaker randomMaker = new RandomMaker(seed);
        List<Integer> result = randomMaker.getRandomThree();

        System.out.println(result.toString());

        String response = "{\"result\":\"" + result.toString() + "\"}";
        System.out.println(response);
        exchange.getResponseHeaders().set("Content-Type", "appication/json");
        exchange.sendResponseHeaders(200, response.length());
        OutputStream os = exchange.getResponseBody();
        os.write(response.getBytes());
        os.close();

    }

    private Integer getSeedFromQuery(String query) throws UnsupportedEncodingException {
        Map<String, Object> parameters = new HashMap<>();
        System.out.println("query : " + query);
        Integer result = 0;

        if (query != null) {
            String pairs[] = query.split("[&]");
            for (String pair : pairs) {
                String param[] = pair.split("[=]");
                System.out.println("0 : " + param[0]);
                System.out.println("1 : " + param[1]);
                result = Integer.parseInt(param[1]);
            }
            return result;
        }else return 0;
    }
}

package javaAPI.gitTest;

import java.util.List;
import java.util.Objects;
import java.util.Random;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class RandomMaker {
    private Integer seed;

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        RandomMaker that = (RandomMaker) o;
        return seed.equals(that.seed);
    }

    @Override
    public int hashCode() {
        return Objects.hash(seed);
    }

    public Integer getSeed() {
        return seed;
    }

    public void setSeed(Integer seed) {
        this.seed = seed;
    }

    public RandomMaker(Integer seed) {
        this.seed = seed;
    }
    public RandomMaker() {this.seed = 0;}

    //억지 스트림과 람다를 써 봄
    public List<Integer> getRandomThree(){
        System.out.println("random maker on!");
        List<Integer> result = Stream.iterate(new Random().nextInt(this.seed), x ->{
            return new Random().nextInt(this.seed);
        }).limit(3).collect(Collectors.toList());
        return  result;
    }
}