Servlet中的请求包含
public class SrcIncludeServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println("include...get....11111");
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
out.println("include1111..get...包含之前...");
//out.flush();
//out.close();
//请求包含
RequestDispatcher rd = request.getRequestDispatcher("/servlet/DestIncludeServlet");
rd.include(request, response);//包含---可理解成类似调用函数的方式。 主要是调用第2个servlet中的service(req,resp)
out.println("include1111..get...包含之后...");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println("include...post....11111");
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println(" <BODY>");
out.println("include1111..post...包含之前...");
//请求包含
RequestDispatcher rd = request.getRequestDispatcher("/servlet/DestIncludeServlet");
rd.include(request, response);//包含
out.println("include1111..post...包含之后...");
out.println(" </BODY>");
out.println("</HTML>");
}
}
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public class DestIncludeServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println("include...get....22222");
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
out.println("include2222..get页面数据输出......");
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println("include...post....22222");
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println(" <BODY>");
out.println("include2222..post页面数据输出......");
out.println(" </BODY>");
out.println("</HTML>");
}
}
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<a href="<%=request.getContextPath()%>/servlet/srcIncludeServlet?name=Jack&age=22">请求包含时，两个servlet的访问顺序, 读取页面数据, 传参</a>
<form action="<%=request.getContextPath()%>/servlet/srcIncludeServlet" method="post">
姓名:<input type="text" name="name"/>
<input type="submit" value="提交">
</form>
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5、请求包含(共享同一个request和response ,类似函数调用中的传参)
1)通过request实现，与转发一样是通过RequestDispatcher，只是前者是rd.forward(req,resp)，后者是rd.include(req,resp);
2)在第1个servlet中out.flush()，对两个servlet的输出都没有影响。但如果在第1个servlet中out.close()，则第1个之后的输出以及第2个servlet中的输出都无效(不会输出)，注意，后面的rd.include()仍然有效即第2个servlet虽然不能输出但仍会执行，且没有异常报出！
3)页面内容输出顺序：
servlet1..包含之前的输出...
servlet2.....(被包含的servlet输出)
servlet1..包含之后的输出...
4)由于该方式和转发一样是共享同一个request和response，因此有关页面参数读取和两个servlet之间的传参特性，同转发!
5)访问顺序(同转发): 第1个GET方式，第2个走的是doGet()。 第1个POST方式，第2个走的是doPost()。
6)一个小细节:被包含servlet中的所有输出信息(包括<html><body>等标记内容)都会原样输出，
//因此要注意，两个servlet之间的输出内容不要出现标记嵌套冲突! ( 如：<html><body><html><body>...</body></html></body></html> )
