java - 如何从存储在 JSON 文件中的 JSON 数组（来自 API）检索数据？

[ { "access_restricted_by_date":true, "id":3155 }, { "access_restricted_by_date":true, "id":4604 }, { "access_restricted_by_date":true, "id":4655 }, { "root_account_id":1, "storage_quota_mb":50000, "template":false, "end_at":null, "public_syllabus_to_auth":false, "public_syllabus":false, "created_at":"2022-08-11T18:00:41Z", "start_at":null, "enrollment_term_id":180, "uuid":"MC24SbWdGDjeKTalLT5T5V41Foh0jD4EybOFG8xY", "course_code":"Study Hall", "course_color":null, "grading_standard_id":null, "workflow_state":"available", "id":6312, "homeroom_course":false, "default_view":"assignments", "is_public_to_auth_users":false, "grade_passback_setting":null, "enrollments":[ { "role":"StudentEnrollment", "enrollment_state":"active", "role_id":3, "user_id":9999, "type":"student", "limit_privileges_to_course_section":false } ], "blueprint":false, "license":"private", "is_public":false } ]

import java.io.*; import com.google.gson.*; import com.google.gson.stream.*; import java.io.IOException; public class CourseGradeReader { public static void main(String args[]) { JsonReader reader; try { reader = new JsonReader(new FileReader("Courses.json")); reader.beginArray(); while(reader.hasNext()) { String name = reader.nextName(); if(name.equals("id")) { System.out.println(reader.nextString()); reader.endArray(); } else { reader.skipValue(); } } reader.endObject(); reader.close(); } catch(Exception e) { e.printStackTrace(); } } }

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; public class CourseGradeReader { public static void main(String args[]) throws IOException, ParseException { JSONParser parser = new JSONParser(); JSONArray a = (JSONArray) parser.parse(new FileReader("Courses.json")); for (Object o : a) { JSONObject course = (JSONObject) o; long id = (long) course.get("id"); System.out.println("Course Id: " + id); String created_at = (String) course.get("created_at"); if(!(created_at == null)) { System.out.println(created_at); } JSONArray enrollments = (JSONArray) course.get("enrollments"); if(!(enrollments == null)) { for (Object c : enrollments) { JSONObject enrollment_list = (JSONObject) c; long user_id = (long) enrollment_list.get("user_id"); System.out.println("User:" + user_id); } } System.out.println("============================"); } } }