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public class Demo1 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } //在servlet中用outputstream输出中文的问题 public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { test4(response); } private void test4(HttpServletResponse response) throws IOException, UnsupportedEncodingException { //如果servle的代码写成这样"response.getOutputStream().write(1);",因为 //浏览器默认的编码是gb2312,那么它会去寻找编号为1所对应的字符,结果是为"", //如果写成字符串"1"的话,那么这个1字符是经过getBytes之后的,所以会直接输出1 response.getOutputStream().write(1); response.getOutputStream().write("1".getBytes()); } private void test3(HttpServletResponse response) throws IOException, UnsupportedEncodingException { String name="中国3"; //如果程序把text/html后面的;写成了,的话,那么浏览器会提示下载此servlet文件 response.setHeader("Content-type", "text/html,charset=UTF-8"); response.getOutputStream().write(name.getBytes("UTF-8")); } private void test2(HttpServletResponse response) throws IOException, UnsupportedEncodingException { String name="中国2"; //用html技术中的meta标签来模拟http的响应头,来控制浏览器的行为 response.getOutputStream().write(" ".getBytes()); response.getOutputStream().write(name.getBytes("UTF-8")); } private void test1(HttpServletResponse response) throws IOException, UnsupportedEncodingException { String name="中国1"; //程序以什么码表输出了,程序就要控制浏览器以什么样的码表打开 response.setHeader("Content-type", "text/html;charset=UTF-8"); //response.getOutputStream().write(name.getBytes()); response.getOutputStream().write(name.getBytes("UTF-8")); }
}
[java] view plain copy public class Demo2 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); }
//通过response的wirter流输出数据
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //因为在servlet传递给浏览器的过程中是通过response进行编码后传递的,而老外默认是 //使用iso8859-1来进行编码传递的,所以我们需要对response的编码进行设置,以控制 //response以什么码表向浏览器写出数据 //测试得知,在设置response的编码时最好写在上面//第一种方式,控制response的编码和浏览器显示的编码,因为浏览器默认是gb2312的 //response.setCharacterEncoding("utf-8"); //下面这句通过response设置浏览器的编码,其实默认同时也把response的编码也给设置了,所以上面的那句话也可以省略掉了 //response.setContentType("text/html;charset=utf-8"); //第二种方式,控制response的编码与浏览器的一致,也就是gb2312编码 response.setCharacterEncoding("gb2312"); String name="中国"; PrintWriter out=response.getWriter(); //第三种方式,不设置response的编码,使用默认的iso8859-1,然后把string转化为8859-1后进行传递 //out.print(new String(name.getBytes(),"iso8859-1")); out.print(name); }
}
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//文件下载 public class Demo3 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String path=this.getServletContext().getRealPath("/download/小破孩.jpg"); String filename=path.substring(path.lastIndexOf("/")+1); //如果下载文件是中文文件,那么文件名需要经过url编码 response.setHeader("content-disposition", "attachment;filename="+URLEncoder.encode(filename,"utf-8")); InputStream is=new FileInputStream(path); OutputStream os=response.getOutputStream(); int len=0; byte[] bs=new byte[1024]; while((len=is.read(bs))>0){ os.write(bs, 0, len); } os.close(); is.close(); }
}
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public class Demo5 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //test1(response); //test2(response); test3(request,response); } //实用的跳转技术,最终的信息还是要在浏览器中显示比较好,这样的话容易排版,test2中是输出的是直接页面的源代码 private void test3(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String message=" 恭喜你,登录成功了,本浏览器将在3秒后,跳到首页,如果没有跳,请点击此处"; request.setAttribute("message", message); this.getServletContext().getRequestDispatcher("/forword.jsp").forward(request, response); } private void test2(HttpServletResponse response) throws IOException { //假设这是一个用于登录的Servlet //假设程序运行到此,用户登录成功了 response.setContentType("text/html;charset=gb2312"); response.setHeader("refresh", "3;url='/testweb/index.jsp'"); response.getWriter().write("恭喜你,登录成功了,本浏览器将在3秒后,跳到首页,如果没有跳,请点击此处"); } private void test1(HttpServletResponse response) throws IOException { response.setHeader("refresh", "3");//每隔三秒刷新一次 int data=new Random().nextInt(1000); response.getWriter().println(data); }
}
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public class Demo5 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //使用expries缓存当前内容 response.setDateHeader("expires", System.currentTimeMillis()+1000*3600); String data="bbbbbbbbbbbbbbbbbb"; System.out.println("访问---"); response.getWriter().write(data); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); }
}
[java] view plain copy
/**- 重定向的特点:
- 1.浏览器会向服务器发送两次请求,意味着就有两个request/response
- 2.用重定向技术,地址栏会发生变化
- *用户登录和购物车时,通常会用到重定向技术
同时调用getOutPutStream()和getWriter()会抛出异常/
public class Demo6 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { /sendRedirect的内部原理 response.setStatus(302); response.setHeader("location", "/testweb/index.jsp");/ response.sendRedirect("/testweb/index.jsp"); }public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { doGet(request, response); }
}