request(请求)和response(响应)

request: 获取请求数据如网页上输入的信息

response：设置响应数据如设置网页显示的信息

 

 如上图，在deGet方法中使用了request来获取页面中的name值，使用response来输出

request获取请求数据（请求头、请求行、请求体）

 

 

 

get和post获取请求参数的方法是不一样的，get是上面的req.getQueryString(),而post是用req.getReader()的

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但是这样写太麻烦了，Servlet提供了几个方法，直接使用下列的方法即可获取请求参数，不用区分是get请求还是post请求

 

例如获取username的值

String username = req.getParameter("username");
System.out.println(username);

解决post中文乱码问题:

用request.CharacterEncoding("UTF-8");设置字符输入流的编码

解决get/post中文乱码问题:

new String(username.getBytes("ISO-8859-1"),"UTF-8");

response.setContextType("text/html;charset=utf-8");

 

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Request请求转发

 

 

 

转发的方法：

@WebServlet("/testServlet")
public class testServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("---正---在---转---发---");
        request.getRequestDispatcher("/test1Servlet").forward(request,response);

 }

@WebServlet("/test1Servlet")
public class test1Servlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("转发成功...");

　　　 　Object msg = request.getAttribute("msg");
　　　 　System.out.println(msg);

 response重定向：

 

 

 

@WebServlet("/respServlet01")
public class respServlet01 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //response.setStatus(302);
        System.out.println("重定向中...");
        //response.setHeader("location", "/tomcat-Demo/respServlet02");

　　　　 response.sendRedirect("/tomcat-Demo/respServlet02");

    }

@WebServlet("/respServlet02")
public class respServlet02 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("重定向成功...");
    }

 

动态获取虚拟目录：

String contextPath  = request.getContextPath();

response.sendRedirect(contextPath + "/xxx")；

 

字符输出流：

    　 response.setContextType("text/html;charset=utf-8");     
　　 　　PrintWriter writer = response.getWriter();
        writer.write("<h1>abcdefg</h1>");

字节输出流请看黑马P108