Rest API via Servlet

Ressources

• https://github.com/Adrien-Courses/R401-EXO-restapi-with-servlet

GET

• préciser le type du contenu lu
• préciser le code de retour (200, 404)
• si un id est précisé chercher l’utilisateur
• sinon retourner l’ensemble des utilisateurs

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    String pathInfo = req.getPathInfo();
 
    resp.setContentType("application/json");
    resp.setCharacterEncoding("UTF-8");
 
    if (pathInfo == null || pathInfo.equals("/")) {
        // Return all users
        Collection<User> users = userDB.values();
        resp.getWriter().write(objectMapper.writeValueAsString(users));
    } else {
        // Get a specific user by ID
        try {
            int userId = Integer.parseInt(pathInfo.substring(1));
            User user = userDB.get(userId);
            if (user != null) {
                resp.getWriter().write(objectMapper.writeValueAsString(user));
            } else {
                resp.setStatus(HttpServletResponse.SC_NOT_FOUND);
                resp.getWriter().write("{\"error\":\"User not found\"}");
            }
        } catch (NumberFormatException e) {
            resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
            resp.getWriter().write("{\"error\":\"Invalid user ID\"}");
        }
    }
}

POST

• préciser le type du contenu retourné
• préciser le code de retour (201)
• retourner l’utilisateur créé

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    BufferedReader reader = req.getReader();
    User newUser = objectMapper.readValue(reader, User.class);
 
    newUser.setId(userIdCounter++);
    userDB.put(newUser.getId(), newUser);
 
    resp.setStatus(HttpServletResponse.SC_CREATED);
    resp.setContentType("application/json");
    resp.getWriter().write(objectMapper.writeValueAsString(newUser));
}

curl -X POST http://localhost:8080/R401-EXO-restapi-with-servlet/users \
     -H "Content-Type: application/json" \
     -d '{"name": "John Doe", "email": "john@example.com"}'

req.getReader()

BufferedReader reader = req.getReader(); // Retrieves the body of the request as character data using a BufferedReader.
User newUser = objectMapper.readValue(reader, User.class);