偶的第一个tag-servlet

最新推荐文章于 2022-04-29 08:53:20 发布

原创最新推荐文章于 2022-04-29 08:53:20 发布 · 816 阅读

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博客详细展示了JSP、Servlet和TLD文件的开发过程。包括建立first.tld文件，定义Xml类，编写HelloWorld Servlet，制作helloworld.jsp页面。通过这些步骤，最终在浏览器输入特定URL可看到结果，涉及到import、session等相关操作。

第一步：建立一个tld
命名为first.tld
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE taglib PUBLIC
"-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN"
"web-jsptaglibrary_1_1.dtd">
<taglib>
    <tlibversion>1.0</tlibversion>
    <jspversion>1.1</jspversion>
    <shortname>first tag</shortname>

    <tag>
        <name>display</name>
        <tagclass>com.bcb.mywork.Xml</tagclass>
        <bodycontent>empty</bodycontent>
        <attribute>
            <name>name</name>
            <required>true</required>
            <rtexprvalue>true</rtexprvalue>
        </attribute>
</tag>
</taglib>

即提出第一个需求，根据此需求，为其定义class
命名为：com.bcb.mywork.Xml.java
/*
* Created on 2004-10-13
*
* To change the template for this generated file go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
package com.bcb.mywork;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.TagSupport;

/**
* @author Administrator
*
* To change the template for this generated type comment go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
public class Xml extends TagSupport {
protected String name;

public int doStartTag() throws JspException {
  Object out =
   pageContext.getAttribute("gettext", PageContext.SESSION_SCOPE);
  System.err.println(out);
  try {

   pageContext.getOut().print(out);
  } catch (java.io.IOException e) {
   throw new JspTagException(e.getMessage());
  }
  return SKIP_BODY;
}

public int doEndTag() throws JspException {
return EVAL_PAGE;
}
public void setName(String Username) {

Username = name;

}

public String getName() {

return name;

}
}

写servlet
命名为:com.bcb.mywork.HelloWorld.java
package com.bcb.mywork;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.RequestDispatcher;
import javax.servlet.Servlet;
import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.jsp.JspWriter;

import com.ibm.CORBA.iiop.Response;

/**
* @version 1.0
* @author
*/
public class HelloWorld extends HttpServlet implements Servlet {

/**
* @see javax.servlet.http.HttpServlet#void (javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
private String context = new String();
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {

  HttpSession session = req.getSession();
  session.setAttribute("gettext", "HelloWorld");
  System.err.println(session);
  String URL = "/helloworld.jsp";
  RequestDispatcher Forward = req.getRequestDispatcher(URL);
  Forward.forward(req, resp);
}

/**
* @see javax.servlet.http.HttpServlet#void (javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
public void doPost(HttpServletRequest req, HttpServletResponse resp)
  throws ServletException, IOException {
  context = req.getParameter("posttext");
  System.out.println(context);
  HttpSession session = req.getSession();
  session.setAttribute("gettext", context);
  String URL = "/helloworld.jsp";
  RequestDispatcher Forward = req.getRequestDispatcher(URL);
  Forward.forward(req, resp);

}

制作jsp页面
命名为：helloworld.jsp
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<HTML>
<HEAD>
<%@ page language="java" contentType="text/html; charset=GBK" pageEncoding="GBK"%>
<%@taglib uri="/WEB-INF/tlds/first.tld" prefix="jet"%>
<META http-equiv="Content-Type" content="text/html; charset=GBK">
<META name="GENERATOR" content="IBM WebSphere Studio">
<TITLE>helloworld.jsp</TITLE>
</HEAD>
<BODY>