jsp通讯录登录与添加

男娘i 2022-05-30 02:15 70阅读 0赞

记录一下Javaee的学习

首先讲一下什么是jsp?

万事先百度。

JSP全名为Java ServerPages，中文名叫java服务器页面，其根本是一个简化的Servlet设计，它是由Sun Microsystems公司倡导、许多公司参与一起建立的一种动态网页技术标准。JSP技术有点类似ASP技术，它是在传统的网页HTML（标准通用标记语言的子集）文件(\*.htm,\*.html)中插入Java程序段(Scriptlet)和JSP标记(tag)，从而形成JSP文件，后缀名为(\*.jsp)。 用JSP开发的Web应用是跨平台的，既能在Linux下运行，也能在其他操作系统上运行。

其实说白了，就是html+java+js+css。sun公司想把java向网页推广的产品，不过确实很成功。

讲一下jsp运行的原理，和设计jsp项目的流程。

不管是jsp还是servlet，当Tomcat服务器开启的时候，tomcat容器都会去加载jsp,说到底最后还是会被jvm编译成一个class文件，jvm认识的java代码会编译成class，不认识的html代码则会被out打印成字符串，留给浏览器解析。其实说到底还是java。

列举到登录验证过程，当用户输入账号和密码，点击提交的时候，form表单则将请求以method(post,get)，账号密码比较重要的数据，一般用post提交，则不会在地址栏显示。此时地址则会改变，比如login.jsp会变成LoginServlet，Servlet做相应逻辑处理，但是做事的还是service，与dao数据库打交道是service，而servlet只是向service要数据。然后servlet通过数据库里的账号和密码验证后，则通过转发或者重定向，跳转到另一个jsp。

因此jsp项目的设计流程是：

表设计--->jdbcUtil-->bean-->service-->jsp-->servlet

一般是先设计数据库，最后再设计servlet，中间大同小异。

废话不多说，直接贴代码。

实现通讯录添加、显示。要求如下：

1） 用户只有登录后才能对通讯录进行添加和查询显示

2） 如果用户没有登录直接访问通讯录维护页面，则提示用户先进行登录，然后点击链接让其跳转至登录页面进行登录。

流程如下：

1） 用户访问登录页面，输入用户名、密码，点击提交，进入servlet验证用户名密码的正确性。

2） 如果验证成功，则跳转至新的jsp页面，显示所有的通讯录信息，并在右上角显示当前登录用户名；如果验证不成功，则跳转至登录页面。

3） 在通讯录显示页面，有一个”添加通讯录”的按钮，点击后进行添加通讯录页面，并进行添加。

4） 退出系统

5） 统计访问人数

环境:myeclipse2014 jdk1.7 mysql tomcat7

mysql数据库表结构

一个用户表(users) 一个用来存储用户好友的表(persons)

users表:

create table users

(

username varchar(10) primary key,

password varchar() not null

)

persons表:

create table persons

(

username varchar(10) references users(username),

id int(20) primary key auto\_increment,

name varchar(10) not null,

tel varchar(30),

address varchar(20)

)

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    %>
    <%
        String num=(String)application.getAttribute("num");
        if(num==null){
        	//第一次访问
        	application.setAttribute("num", "1");
        }else{
        	int num_ = Integer.parseInt(num);
        	num_ +=1;
        	application.setAttribute("num", String.valueOf(num_));
        }
     %>
    <!DOCTYPE>
    <html>
      <head>
        <base href="<%=basePath%>">
        
        <title>Login</title>
      </head>
      
      <body>
      <p>网站访问次数,<%=application.getAttribute("num") %></p>
       	<form action="AddressServlet" method="post">
       		用户名:<input type="text" id="username" name="username" size="20" required="required"/>
       		密码:<input type="password" id="password" name="password" size="20" required="required"/>
       		<input type="hidden" id="type" name="type" value="login"/>
       		<input type="submit" value="提交"> 
       	</form>
      </body>
    </html>

list.jsp(显示信息界面)

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    %>
    <%@ page import="com.work.bean.Person" %>
    
    <!DOCTYPE>
    <html>
      <head>
        <base href="<%=basePath%>">
        <title>list</title>
      </head>
      
      <body>
      <p>当前在线人数:${userCounts }</p>
      <p>正在登录的用户是:<%=request.getAttribute("user") %></p>
      <a href="add.jsp">添加通讯录</a>
        <div>
       	<table border="1" style="border-collapse:collapse">
       		<tr>
    	   		<th>用户编号</th>
    	   		<th>姓名</th>
    	   		<th>手机</th>
    	   		<th>地址</th>
       		</tr>
       			<%
       			Object getlists=request.getAttribute("personlists");
       			ArrayList<Person> personlists=(ArrayList<Person>)getlists;
       		
       		
       			if(personlists!=null)
       			{
       				for(Person p:personlists)
       				{
       			%>
       					<tr>
       						<td>
       							<%= p.getId() %>
       						</td>
       						<td>
       							<%= p.getName() %>
       						</td>
       						<td>
       							<%= p.getTel() %>
       						</td>
       						<td>
       							<%= p.getAddress() %>
       						</td>
       					</tr>
       			<% 
       				}
       			}
       			else
       			{%>
       				<tr>
       					<td>没有数据</td>
       				</tr>
       			 <%
       			}
       			%>
       	</table>
       </div> 
      </body>
    </html>

add.jsp(通讯录添加好友)

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    %>
    
    <!DOCTYPE>
    <html>
      <head>
        <base href="<%=basePath%>">
        
        <title>add</title>
        
    
      </head>
      
      <body>
      <form action="AddressServlet" method="post">
        姓名<input type="text" id="name" name="name" size="20" required="required"/>
        手机<input type="text" id="tel" name="tel" size="20" required="required"/>
        地址<input type="text" id="address" name="address" size="20" required="required"/>
        <input type="hidden" id="type" name="type" value="add">
        <input type="submit" value="添加"/>
       </form>
      </body>
    </html>

AddressServlet(web层)

package com.work.web;
    
    import java.io.IOException;
    import java.io.PrintWriter;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import com.work.bean.Person;
    import com.work.bean.User;
    import com.work.dao.PUtil;
    import com.work.service.AddressService;
    
    public class AddressServlet extends HttpServlet {
    
    	public void doGet(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
    		String username=request.getParameter("username");
    		String password=request.getParameter("password");
    		String name=request.getParameter("name");
    		String tel=request.getParameter("tel");
    		String address=request.getParameter("address");
    		String type=request.getParameter("type");
    		User user;
    		Person p;
    		if(!"".equals(username))
    		{
    			user=new User(username,password);
    			request.setAttribute("user", username);
    		}
    		if(!"".equals(type)&&type!=null&&!"".equals(username)&&"login".equals(type))
    		{
    			if(AddressService.islogin(username, password))
    			{
    				user = new User(username, password);
    				request.setAttribute("personlists", AddressService.list(username));
    				//request.setAttribute("adminname", adminname);
    				request.getSession().setAttribute("user", user);
    				PUtil.uname=username;
    				request.getRequestDispatcher("/list.jsp").forward(request, response);
    			}
    			else
    			{
    				request.getRequestDispatcher("/login.jsp").forward(request, response);
    			}
    			
    		}
    		if(!"".equals(type)&&type!=null&&!"".equals(username)&&"add".equals(type))
    		{
    			p=new Person(name, tel, address);
    			if(AddressService.add(p,PUtil.getUname()))
    			{
    				request.setAttribute("user", PUtil.uname);
    				request.setAttribute("personlists", AddressService.list(PUtil.uname));
    				request.getRequestDispatcher("/list.jsp").forward(request, response);
    			}
    			else
    			{
    				request.getRequestDispatcher("/add.jsp").forward(request, response);
    			}
    		}
    		
    	}
    	public void doPost(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
    		this.doGet(request, response);
    	}
    
    }

AddressService.java(service层)

package com.work.service;
    
    import java.util.ArrayList;
    
    import com.work.bean.Person;
    import com.work.dao.PUtil;
    
    public class AddressService {
    	//登录验证
    	public static boolean islogin(String username,String pwd)
    	{
    		return PUtil.islogin(username, pwd);
    	}
    	//查看通讯录里的好友
    	public static ArrayList<Person> list(String username)
    	{
    		return PUtil.list(username);
    	}
    	//添加通讯录好友
    	public static boolean add(Person p,String username)
    	{
    		return PUtil.add(p, username);
    	}
    	//添加新用户
    	public static boolean addUser(String username,String pwd)
    	{
    		return PUtil.addUser(username, pwd);
    	}
    }

`SessionListener.java(监听器)`

package com.work.listener;
    
    import javax.servlet.http.HttpSessionAttributeListener;
    import javax.servlet.http.HttpSessionBindingEvent;
    import javax.servlet.http.HttpSessionEvent;
    import javax.servlet.http.HttpSessionListener;
    
    public class SessionListener implements HttpSessionListener,HttpSessionAttributeListener{
        private int userCounts = 0;//在线人数
    	@Override
    	public void attributeAdded(HttpSessionBindingEvent be) {
    		System.out.println("session添加属性"+be.getName()+"--"+be.getValue());
    		
    	}
    
    	@Override
    	public void attributeRemoved(HttpSessionBindingEvent be) {
    		System.out.println("session移除属性"+be.getName()+"--"+be.getValue());
    		
    	}
    
    	@Override
    	public void attributeReplaced(HttpSessionBindingEvent be) {
    		System.out.println("session替换属性"+be.getName()+"--"+be.getValue());
    		
    	}
    
    	@Override
    	public void sessionCreated(HttpSessionEvent se) {
    		userCounts++;
    		se.getSession().setAttribute("userCounts", userCounts);
    		System.out.println("新的会话创建===="+se.getSession().getId());
    	}
    
    	@Override
    	public void sessionDestroyed(HttpSessionEvent se) {
    	    userCounts--;
    	    se.getSession().setAttribute("userCounts", userCounts);
    	    System.out.println("会话销毁===="+se.getSession().getId());
    		
    	}
    
    }

`Afilter.java(过滤器)`

package com.work.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.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    public class Afilter implements Filter {
    
    	@Override
    	public void doFilter(ServletRequest arg0, ServletResponse arg1,
    			FilterChain arg2) throws IOException, ServletException {
    		// TODO Auto-generated method stub
    		HttpServletRequest request=(HttpServletRequest)arg0;
    		HttpServletResponse response=(HttpServletResponse)arg1;
    		String currentURL = request.getRequestURI();   
            String targetURL = currentURL.substring(currentURL.indexOf("/", 1),  
                    currentURL.length());  
            HttpSession session = request.getSession(false);  
            if (!"/login.jsp".equals(targetURL)) {// 判断当前页是否是重定向以后的登录页面页面，如果是就不做session的判断，防止出现死循环  
                if (session == null || session.getAttribute("user") == null) {  
                    // *用户登录以后需手动添加session  
                    System.out.println("request.getContextPath()="  
                            + request.getContextPath());  
                    response.sendRedirect(request.getContextPath() + "/login.jsp");  
                    // 如果session为空表示用户没有登录就重定向到login.jsp页面  
                    return;  
                }  
            }  
            // 加入filter链继续向下执行  
            arg2.doFilter(request, response);  
    	}
    
    	@Override
    	public void destroy() {
    		// TODO Auto-generated method stub
    		System.out.println("过滤器已经回收...");
    	}
    
    	@Override
    	public void init(FilterConfig arg0) throws ServletException {
    		// TODO Auto-generated method stub
    		System.out.println("过滤器正在过滤...");
    	}
    
    }

PUtil.java(dao层)

package com.work.dao;
    
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.util.ArrayList;
    
    import com.work.bean.Person;
    
    
    
    public class PUtil {
    	static Connection conn;
    	static PreparedStatement ps;
    	static ResultSet rs;
    	static ArrayList<Person> plists;
    	public static String uname;
    	private static final String DBDRIVER="com.mysql.jdbc.Driver";
    	private static String USERNAME="root";
    	private static String PASSWORD="123456";
    	private static String URL="jdbc:mysql://localhost:3306/qq";
    	//添加用户
    	public static boolean addUser(String username,String pwd)
    	{
    		try {
    			Class.forName(DBDRIVER);
    			conn=DriverManager.getConnection(URL, USERNAME, PASSWORD);
    			String sql="insert into users values(?,?)";
    			ps=conn.prepareStatement(sql);
    			ps.setString(1, username);
    			ps.setString(2, pwd);
    			ps.execute();
    			return true;
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (ClassNotFoundException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}finally{
    			try {
    				ps.close();
    				conn.close();
    			} catch (SQLException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    		}
    		return false;
    	}
    	//验证用户登录
    	public static boolean islogin(String username,String pwd)
    	{
    		try {
    			Class.forName(DBDRIVER);
    			conn=DriverManager.getConnection(URL, USERNAME, PASSWORD);
    			String sql="select * from users where username=? and password=?";
    			ps=conn.prepareStatement(sql);
    			ps.setString(1, username);
    			ps.setString(2, pwd);
    			rs=ps.executeQuery();
    			while(rs.next())
    			{
    				if(rs.getString("username").equals(username)&&rs.getString("password").equals(pwd))
    				{
    					return true;
    				}
    			}
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (ClassNotFoundException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}finally{
    			try {
    				rs.close();
    				ps.close();
    				conn.close();
    			} catch (SQLException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    		}
    		return false;
    	}
    	//查看全部
    	public static ArrayList<Person> list(String username)
    	{
    		Person person;
    		try {
    			Class.forName(DBDRIVER);
    			conn=DriverManager.getConnection(URL, USERNAME, PASSWORD);
    			String sql="select * from persons where username=?";
    			ps=conn.prepareStatement(sql);
    			ps.setString(1, username);
    			rs=ps.executeQuery();
    			plists=new ArrayList<>();
    			while(rs.next())
    			{
    				person=new Person(rs.getInt("id"),rs.getString("name"),rs.getString("tel"), rs.getString("address"));
    				plists.add(person);
    			}
    			return plists;
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (ClassNotFoundException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}finally{
    			try {
    				rs.close();
    				ps.close();
    				conn.close();
    			} catch (SQLException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    		}
    		return null;
    	}
    	//添加通讯录的好友
    	public static boolean add(Person p,String username)
    	{
    		try {
    			Class.forName(DBDRIVER);
    			conn=DriverManager.getConnection(URL, USERNAME, PASSWORD);
    			String sql="insert into persons(username,name,tel,address) values(?,?,?,?)";
    			ps=conn.prepareStatement(sql);
    			ps.setString(1,username);
    			ps.setString(2, p.getName());
    			ps.setString(3, p.getTel());
    			ps.setString(4, p.getAddress());
    			ps.execute();
    			return true;
    		} catch (SQLException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (ClassNotFoundException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}finally{
    			try {
    				ps.close();
    				conn.close();
    			} catch (SQLException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    		}
    		return false;
    	}
    	public static String getUname() {
    		return uname;
    	}
    	public static void setUname(String uname) {
    		PUtil.uname = uname;
    	}
    	
    }

Person.java(bean)

package com.work.bean;
    
    public class Person {
    	int id; 
    	String name;
    	String tel;
    	String address;
    	public Person() {
    	}
    	
    	public Person(int id,String name, String tel, String address) {
    		this.id=id;
    		this.name = name;
    		this.tel = tel;
    		this.address = address;
    	}
    	public Person(String name, String tel, String address) {
    		this.name = name;
    		this.tel = tel;
    		this.address = address;
    	}
    	
    	public int getId() {
    		return id;
    	}
    
    	public void setId(int id) {
    		this.id = id;
    	}
    
    	public String getName() {
    		return name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    	public String getTel() {
    		return tel;
    	}
    	public void setTel(String tel) {
    		this.tel = tel;
    	}
    	public String getAddress() {
    		return address;
    	}
    	public void setAddress(String address) {
    		this.address = address;
    	}
    	
    }

User.java(bean)

package com.work.bean;
    
    public class User {
    	String username;
    	String password;
    	public User()
    	{
    		
    	}
    	
    	public User(String username, String password) {
    		super();
    		this.username = username;
    		this.password = password;
    	}
    
    	public String getUsername() {
    		return username;
    	}
    	public void setUsername(String username) {
    		this.username = username;
    	}
    	public String getPassword() {
    		return password;
    	}
    	public void setPassword(String password) {
    		this.password = password;
    	};
    	
    }

web.xml(配置文件有很严格的顺序要求 filter-->servlet-->listener-->session)

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
    <web-app>
        
        <filter>
            <filter-name>Afilter</filter-name>
            <filter-class>com.work.filter.Afilter</filter-class>
             <init-param>
                <param-name>encoding</param-name>
                <param-value>utf-8</param-value>
            </init-param>
        </filter>
        <filter-mapping>
            <filter-name>Afilter</filter-name>
            <url-pattern>*.jsp</url-pattern>
            
        </filter-mapping>
        
      <listener>
       <listener-class>com.work.listener.SessionListener</listener-class>
      </listener>
      <servlet>
        <servlet-name>AddressServlet</servlet-name>
        <servlet-class>com.work.web.AddressServlet</servlet-class>
      </servlet>
      <servlet-mapping>
        <servlet-name>AddressServlet</servlet-name>
        <url-pattern>/AddressServlet</url-pattern>
      </servlet-mapping>
      
      <session-config>
        <session-timeout>1</session-timeout>
      </session-config>
    </web-app>

还有mysql jdbc jar 可以去mysql官网下载

[https://dev.mysql.com/downloads/connector/j/][https_dev.mysql.com_downloads_connector_j]

[https_dev.mysql.com_downloads_connector_j]: https://dev.mysql.com/downloads/connector/j/