HttpSesponseServlet
(HttpSesponseServlet object is the server response object, the object encapsulates data sent to the client, sending the first response, the response status code transmission method)
Setting response header, in the manner of a key-yalue key set, if the presence of the same key, the value of the value will cover
response.setHeader("x1","x2");
response.setHeader("x1","x22");
Setting response header, in the manner of a key-yalue key set, if the presence of the same key, the value will not be overwritten by the values
response.addHeader("hello","word");
response.addHeader("hello","word");
Setup Response Status Code
response.sendError(404,"not found");
The server returns the object data to be rendered in accordance with the requirements of a certain format, HTML format will only be an identification tag
response.setContentType("text/java");
response.getWriter().write("<b>java is easy</b>");