java 留言板源代码简单的javaweb留言板设计

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恋上一只猪 2023-08-29 18:30:17

文章标签 java 留言板源代码 java xml html 文章分类 Java 后端开发

前端编写：index.jsp message.jsp
index.jsp编写:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>管理界面</title>
<link href="form.css" rel="stylesheet" type="text/css"/>
</head>
<body>
<%
	String flag = request.getParameter("flag");
%>
	<script type="text/javascript">
		var flag = <%= flag%>;
		if(flag == "404")
		{
			alert("请先登录后操作！");
		}
	</script>
	<form action="login.jsp" method="post" class="smart-green">
		<h1>系统管理</h1>
		<label>
			<span>用户名：</span>
			<input type="text" placeholder="请输入用户名" name="username"/>
		</label>
		
		<label>
			<span>密码：</span>
			<input type="password" placeholder="请输入密码" name="password"/>
		</label>
		<input value="点击登录" type="submit" />
	</form>
	
</body>
</html>

基础验证这边不实现验证功能，只判断是否为空：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%
	//进行账号密码的验证
	String username = request.getParameter("username");
	String password = request.getParameter("password");
	request.getSession().setAttribute("loginName", username);
	response.sendRedirect(request.getContextPath()+"/message.jsp");//进行页面的跳转，request.getContextPath()获取本地地址；
%>

message.jsp编写：

<%@page import="model.message"%>
<%@page import="java.util.List"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>留言板使用</title>
<link href="form.css" rel="stylesheet" type="text/css" />
<link href="table.css" rel="stylesheet" type="text/css"/>
</head>
<body>
<%
	String userName = (String)session.getAttribute("loginName");
	String subFlag = request.getParameter("subFlag");
	List<message> messages = (List<message>)session.getAttribute("message");
%>
<script type="text/javascript">
	var flag = '<%= subFlag%>';
	if(flag == "1")
	{
		alert("留言成功！");
	}
</script>
	<form action="/FilterDemo/messageServlet" method="get" class="smart-green">
		<h1>留言板的编写</h1>
		<label>
			<span>留言人：</span>
			<input type="text" placeholder="请输入标题" value="<%=userName %>" name="name"/>
		</label>
		<label>
			<span>标题：</span>
			<input type="text" placeholder="请输入标题" name="title"/>
		</label>
		<label>
			<span>内容:</span>
			<textarea name="content"></textarea>
		</label>
		<input type="submit" value="提交留言"/>
	</form>
	<br/>
	<table id="table-3" width="85%" align="center">
		<tr>
			<th width="15％">留言人</th>
			<th width="15%">标题</th>
			<th width="70%">内容</th>
		</tr>
		<%
			if(messages != null)
			{
				for(message ms : messages)
				{
		%>
		<tr>
			<td><%=userName %></td>
			<td><%=ms.getTitle() %></td>
			<td><%=ms.getContent() %></td>
		</tr>
		<%
				}
			}
		%>
	</table>
</body>
</html>

模块化数据，进行调用：

package model;

public class message {
	//用来封装数据
	private String title;
	private String content;
	public message(String title, String content) {
		super();
		this.title = title;
		this.content = content;
	}
	public message() {
	}
	public String getTitle() {
		return title;
	}
	public void setTitle(String title) {
		this.title = title;
	}
	public String getContent() {
		return content;
	}
	public void setContent(String content) {
		this.content = content;
	}
	
}

留言板进行基本的数据处理：

package cn.java.servlet;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

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 model.message;

/**
 * Servlet implementation class messageServlet
 */
@WebServlet("/messageServlet")
public class messageServlet extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		String title = request.getParameter("title");
		String content = request.getParameter("content");
		message ms = new message();
		ms.setTitle(title);
		ms.setContent(content);
		List<message> list = (List<message>)request.getSession().getAttribute("message");
		if(list == null)
		{
			list = new ArrayList<message>();
			request.getSession().setAttribute("message", list);
		}
		list.add(ms);
		response.sendRedirect(request.getContextPath()+"/message.jsp?subFlag=1");//重定向跳转地址；
	}
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}

css编写：省略；
关于过滤器的编写：进行全局过滤器测试：
Fileter编写

package cn.java.filter;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebFilter("/Fileter")
//实例化接口
public class Fileter implements Filter {
	private FilterConfig config;
    public Fileter() {
    }

	public void destroy() {
		//过滤器使用操作，最后一次使用，最后面做清除操作 
		System.out.println("characterEncodigFilter destroy....");
	}
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) 
			throws IOException, ServletException {
		//过滤器的方法，进行过滤器的操作
		//获取对象的时候做一些基本操作
		System.out.println("characterEncodigFilter doFilter..");//获取对象时候被使用，第二次操作，每次刷新都执行
		//1.注册过滤器需要在web.xml文件里面注册
		String sysName = config.getInitParameter("systemName");
		String version = config.getInitParameter("version");
		System.out.println(sysName);
		System.out.println(version);
		//这边可以设置网页的编码格式
		request.setCharacterEncoding(config.getInitParameter("encoding"));
		//2.拦截映射配置
		chain.doFilter(request, response);
		
	}
	public void init(FilterConfig Config) throws ServletException {
		//获取配置对象；
		System.out.println("characterEncodigFilter init...");//只有第一次调用的时候被使用，启动时第一步操作
		this.config = Config;
	}

	public FilterConfig getConfig() {
		return config;
	}

	public void setConfig(FilterConfig config) {
		this.config = config;
	}

}

进行web.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>FilterDemo</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <!-- 注册过滤器 -->
  <filter>
  	<filter-name>FileterEncodig</filter-name>
  	<filter-class>cn.java.filter.Fileter</filter-class>
  	<init-param>
  		<param-name>systemName</param-name>
  		<param-value>filterEncodig</param-value>
  	</init-param>
  	<init-param>
  		<param-name>version</param-name>
  		<param-value>1.0</param-value>
  	</init-param>
  	<init-param>
  		<param-name>encoding</param-name>
  		<param-value>UTF-8</param-value>
  	</init-param>
  </filter>
  <!-- 做本地过滤器映射 -->
  <filter-mapping>
  	<filter-name>FileterEncodig</filter-name>
  	<url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

可以获取版本，编码格式，等操作；<url-pattern>/*</url-pattern>用来做那个jsp页面会被调用；
进行基本的是否登录验证：利用过滤器：

package cn.java.filter;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebFilter("/SessionFileter")
public class SessionFileter implements Filter {
	public void destroy() {
	}
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		//进行是否登录验证,不一定需要过滤器来验证，也可以用其他方式
		HttpServletRequest hrequest = (HttpServletRequest)request;
		HttpServletResponse hresponse = (HttpServletResponse)response;
		String userLogin = (String)hrequest.getSession().getAttribute("loginName");
		if(userLogin == null)
		{
			hresponse.sendRedirect(hrequest.getContextPath()+"/index.jsp?flag=404");
			return;
		}else {
			chain.doFilter(request, response);
			return;
		}
	}
	public void init(FilterConfig fConfig) throws ServletException {
		//这里面用来初始化配置
	}

}

也需要进行web.xml配置：

<!-- 用于做用户是否登录的过滤器验证 -->
	<filter>
		<filter-name>sessionFilter</filter-name>
		<filter-class>cn.java.filter.SessionFileter</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>sessionFilter</filter-name>
		<url-pattern>/message.jsp</url-pattern><!-- 用于配置是否使用在哪个页面 -->
	</filter-mapping>

最后实现效果：

java 留言板源代码简单的javaweb留言板设计_java