Java Web-servlet技术-重定向与转发

最新推荐文章于 2025-04-27 14:10:12 发布

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本文介绍如何使用 Java Servlet 进行基本的表单验证，包括姓名和年龄的检查。通过重定向和转发实现错误提示和成功显示用户信息。

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1.创建Verify.java的servlet文件,重写doGet()方法

package myservlet;

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

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.swing.JOptionPane;

/**
 * Servlet implementation class Verify
 */
@WebServlet("/Verify")
public class Verify extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Verify() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		String name=request.getParameter("name");
		String age=request.getParameter("age");
		PrintWriter out=response.getWriter();
		int numberAge=Integer.parseInt(age);
		if(name.length()==0||name==null) {
			response.sendRedirect("show.jsp");
			
		}
		else if(age.length()==0||age==null) {
			response.sendRedirect("show.jsp");
			out.print("<br><font color=blue size=4>请输入您的年龄");
		}
		else if(numberAge<=0||numberAge>=150) {
			JOptionPane.showMessageDialog(null, "你输入的数字不符合常理！", "\"请确认您的年龄是否是:\""+numberAge, JOptionPane.ERROR_MESSAGE);
			response.sendRedirect("show.jsp");

		}
		else { 
			RequestDispatcher dispatcher=request.getRequestDispatcher("showMessage");
			dispatcher.forward(request,response);
		}
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

2.创建重定向目标ShowMessage.java的servlet文件,重写doGet()方法

package myservlet;

import java.io.*;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class ShowMessage
 */
@WebServlet("/ShowMessage")
public class ShowMessage extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ShowMessage() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		PrintWriter out=response.getWriter();
		String name=request.getParameter("name");
		String age=request.getParameter("age");
		out.print("<br><font color=blue size=4>您的姓名是：");
		out.print(name);
		out.print("<br><font color=pink size=4>您的年龄是：");
		out.print(age);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

3.配置web.xml

4.创建show.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>重定向与转发</title>
</head>
<body>
<form action="verify" method="get">
  输入姓名：<input type="text" name=name>
  <br>
  输入年龄：<input type="text" name=age>
  <br>
  <input type="submit" value="提交"/>
</form>

</body>
</html>

5.运行