HttpServletResponse
기본 사용법
@WebServlet(name = "ResponseHeaderServlet", urlPatterns = "/response-header")
public class ResponseHeaderServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// status-line
response.setStatus(HttpServletResponse.SC_OK);
// response-header
response.setHeader("Content-Type", "text/plain;charset=UTF-8");
response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate");
response.setHeader("Pragma", "no-cache");
response.setHeader("my-header", "hello");
// header 편의 메서드
// content(response);
// cookie(response);
redirect(response);
// message body
PrintWriter writer = response.getWriter();
writer.println("OK");
}
public void content(HttpServletResponse response) {
response.setContentType("text/plain");
response.setCharacterEncoding("UTF-8");
// response.setContentLength(2); // 생략 시 자동 생성
}
public void cookie(HttpServletResponse response) {
Cookie cookie = new Cookie("myCookie", "good");
cookie.setMaxAge(600); // 600초
response.addCookie(cookie);
}
private void redirect(HttpServletResponse response) throws IOException {
response.sendRedirect("/basic/hello-form.html");
}
}HTTP 응답 데이터
단순 텍스트
HTML 응답
@WebServlet(name = "responseHtml", urlPatterns = "/response-html")
public class ResponseHtmlServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
response.setCharacterEncoding("UTF-8");
PrintWriter writer = response.getWriter();
writer.println("<html>");
writer.println("<body>");
writer.println("<h1>Hello World!</h1>");
writer.println("</body>");
writer.println("</html>");
}
}HTTP API - MassageBody JSON 응답
@WebServlet(name = "responseJsonServlet", urlPatterns = "/response-json")
public class ResponseJsonServlet extends HttpServlet {
private ObjectMapper objectMapper = new ObjectMapper();
@Override
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
HelloData helloData = new HelloData();
helloData.setUsername("JEONG");
helloData.setAge(20);
// JSON 형식으로 변환
String result = objectMapper.writeValueAsString(helloData);
response.getWriter().write(result);
}
}
Java Back-End 2022.11.01 💻~ing