public class ResponseServlet extends HttpServlet {
/**
* 1、tomcat服务器把请求信息封装到HttpServletRequest对象，且把响应信息封装到HttpServletResponse
* 2、tomcat服务器调用doGet方法，传入request，和response对象
* 3、通过response对象改变响应信息
* 4、tomcat服务器把response对象的内容转换成响应格式内容，再发送给浏览器解析
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
/**
* 设置响应实体内容编码
*/
//response.setCharacterEncoding("utf-8");
/**
* 3.1 响应行
*/
//修改状态码
//response.setStatus(404);
// 发送404的状态码+404的错误页面
//response.sendError(404);
/**
* 3.2 响应头
*/
//response.setHeader("server", "JBoss");
/**
* 3.3 实体内容(浏览器直接能够看到的内容就是实体内容)
*/
//字符内容。
//response.getWriter().write("hello world");
//字节内容
//response.getOutputStream().write("hello world".getBytes());
/**
* 请求重定向： 发送一个302状态码 + location的响应头
*/
//发送一个302状态码
//response.setStatus(302);
//location的响应头
//response.setHeader("location", "/myweb/adv.html");
//请求重定向简化写法
//response.sendRedirect("/myweb/adv.html");
/**
* 定时刷新
* 原理：浏览器认识refresh头，得到refresh头之后重新请求当前资源
*/
//每隔1秒刷新次页面
//response.setHeader("refresh", "1");
/**
* 隔n秒之后跳转另外的资源
*/
//隔3秒之后跳转到adv.html
//response.setHeader("refresh", "3;url=/myweb/adv.html");
// 打开图片
/*response.setContentType("image/jpg");
File file = new File("e://test.jpg");
FileInputStream inputStream = new FileInputStream(file);
int len = 0;
byte[] byt = new byte[1024];
while ((len = inputStream.read(byt)) != -1){
response.getOutputStream().write(byt,0,len);
}*/
// 以下载的方式打开图片
File file = new File("e://image.jpg");
FileInputStream inputStream = new FileInputStream(file);
response.setHeader("Content-Disposition","attachment; filename="+file.getName());
int len = 0;
byte[] byt = new byte[1024];
while ((len = inputStream.read(byt)) != -1){
response.getOutputStream().write(byt,0,len);
}
}
/**
*
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request,response);
}
}
