response.setHeader("x1","x2");
response.setHeader("x1","x22");
response.addHeader("hello","word");
response.addHeader("hello","word");
response.sendError(404,"not found");
response.setContentType("text/java");
response.getWriter().write("<b>java is easy</b>");
原文：https://www.cnblogs.com/-xsw000/p/12632121.html