[转载]RequestDispatcher.include(String str)用法。

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只是在书上看到了RequestDispatcher对象的Include方法可以将多个单功能的文件例如.jsp文件整合成一个Servlet文件

今天上网找到一个很好的实例来说明这一点。很感谢此作者！^_^

public class TestDispatcher extends javax.servlet.http.HttpServlet implements

javax.servlet.Servlet ...{

public TestDispatcher() ...{

super();

}

protected void doGet(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException ...{

doPost(request, response);

}

protected void doPost(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException ...{

RequestDispatcher rd ;

rd = request.getRequestDispatcher("TestDispatcher1");

rd.include(request, response);

//String hello = (String) request.getAttribute("hello");

//System.out.println(hello);

rd = request.getRequestDispatcher("/test/test51.jsp");

rd.include(request, response);

rd = request.getRequestDispatcher("/test/test5.jsp");

rd.include(request, response);

}

public class TestDispatcher1 extends javax.servlet.http.HttpServlet implements

javax.servlet.Servlet ...{

public TestDispatcher1() ...{

super();

}

protected void doGet(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException ...{

doPost(request, response);

}

protected void doPost(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException ...{

request.setAttribute("hello", "hello");

response.getWriter().write("this is servlet2<br>");

response.sendRedirect("http://www.csdn.net");

}

<%...@ page language="java" contentType="text/html; charset=ISO-8859-1"

pageEncoding="ISO-8859-1"%>

<%...@ taglib uri="/WEB-INF/c.tld" prefix="c" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<title>Insert title here</title>

</head>

<body>

<c:out value="${hello}"></c:out>

<br>

this is test51.jsp.

<br>

</body>

</html>

<%...@ page language="java" contentType="text/html; charset=ISO-8859-1"

pageEncoding="ISO-8859-1"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<title>Insert title here</title>

</head>

<body>

this is test5.jsp.

</body>

</html>

输出结果：     this is servlet2
                    hello
                    this is test51.jsp
                    this is test5.jsp

总结：servlet1中include另外一个servlet2,会计算servlet2,最终转向servlet1决定，servlet2中的request和response对象中存储的数据被和并到servlet1的request和response对象中。

servlet中include一个jsp页，相当于：jsp中<%@ include file="XXX.jsp" %>

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