ApiFindUserServlet.java

package net.slipp.user.web;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.slipp.user.User;
import net.slipp.user.UserDAO;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

@WebServlet("/api/users/find")
public class ApiFindUserServlet extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		String userId = req.getParameter("userId");
		if (userId == null) {
			resp.sendRedirect("/");
			return;
		}

		UserDAO userDao = new UserDAO();
		User user = userDao.findByUserId(userId);
		if (user == null) {
			return;
		}

		final GsonBuilder builder = new GsonBuilder();
		builder.excludeFieldsWithoutExposeAnnotation();
		final Gson gson = builder.create();

		String jsonData = gson.toJson(user);
		resp.setContentType("application/json;charset=UTF-8");

		PrintWriter out = resp.getWriter();
		out.print(jsonData);
	}
}