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Java组件javabean用户登录实例详解

时间:2020-05-04 14:06     来源/作者:flab100

本文简单讲述使用javabean实现用户登录,包括用户登录,注册和退出等。

1.关于javabean
JavaBean 是一种JAVA语言写成的可重用组件。为写成JavaBean,类必须是具体的和公共的,并且具有无参数的构造器。JavaBean 通过提供符合一致性设计模式的公共方法将内部域暴露成员属性,set和get方法获取。众所周知,属性名称符合这种模式,其他Java 类可以通过自省机制发现和操作这些JavaBean 的属性。

2.系统架构
2.1登录用例图

Java组件javabean用户登录实例详解

2.2页面流程图

Java组件javabean用户登录实例详解

2.3系统架构图

Java组件javabean用户登录实例详解

2.4数据库设计
本例使用oracle数据库

用户表包括id,用户名,密码,email,共4个字段

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-- Create table
create table P_USER
(
 id  VARCHAR2(50) not null,
 username VARCHAR2(20),
 password VARCHAR2(20),
 email VARCHAR2(50)
)
tablespace USERS
 pctfree 10
 initrans 1
 maxtrans 255
 storage
 (
 initial 64
 minextents 1
 maxextents unlimited
 );
-- Add comments to the table
comment on table P_USER
 is '用户表';
-- Add comments to the columns
comment on column P_USER.id
 is 'id';
comment on column P_USER.username
 is '用户名';
comment on column P_USER.password
 is '密码';
comment on column P_USER.email
 is 'email';

3.javabean编写
3.1开发数据库底层处理javabean
DBAcess.java

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package com.baosight.bean;
 
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
 
/**数据库操作类
 * <p>Title:DBAcess </p>
 * <p>Description:TODO </p>
 * <p>Company: </p>
 * @author yuan
 * @date 2016-5-22 下午12:40:24*/
public class DBAcess {
 private String driver = "oracle.jdbc.driver.OracleDriver";
 private String url = "jdbc:oracle:" + "thin:@127.0.0.1:1521:orcl";
 private String username = "scott";
 private String password = "tiger";
 private Connection conn;
 private Statement stm;
 private ResultSet rs;
 //创建连接
 public boolean createConn() {
  boolean b = false;
  try {
   Class.forName(driver);// 加载Oracle驱动程序
   conn = DriverManager.getConnection(url, username, password);
   b = true;
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }// 获取连接
  catch (ClassNotFoundException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  return b;
 }
 //修改
 public boolean update(String sql){
  boolean b = false;
  try {
   stm = conn.createStatement();
   stm.execute(sql);
   b = true;
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  return b;
 }
 //查询
 public void query(String sql){
  try {
   stm = conn.createStatement();
   rs = stm.executeQuery(sql);
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }
 //判断有无数据
 public boolean next(){
  boolean b = false;
  try {
   if(rs.next()){
    b = true;
   }
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  return b;
 }
 //获取表字段值
 public String getValue(String field) {
  String value = null;
  try {
   if (rs != null) {
    value = rs.getString(field);
   }
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  return value;
 }
 //关闭连接
 public void closeConn() {
  try {
   if (conn != null) {
    conn.close();
   }
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }
 //关闭statement
 public void closeStm() {
  try {
   if (stm != null) {
    stm.close();
   }
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }
 //关闭ResultSet
 public void closeRs() {
  try {
   if (rs != null) {
    rs.close();
   }
  } catch (SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }
 public String getDriver() {
  return driver;
 }
 public void setDriver(String driver) {
  this.driver = driver;
 }
 public String getUrl() {
  return url;
 }
 public void setUrl(String url) {
  this.url = url;
 }
 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;
 }
 public Statement getStm() {
  return stm;
 }
 public void setStm(Statement stm) {
  this.stm = stm;
 }
 public ResultSet getRs() {
  return rs;
 }
 public void setRs(ResultSet rs) {
  this.rs = rs;
 }
 public void setConn(Connection conn) {
  this.conn = conn;
 }
 public Connection getConn() {
  return conn;
 }
}

上述数据库操作类使用JDBC连接数据库,并封装了连接数据库、查询、修改、关闭资源等方法。

3.2开发JavaBean业务逻辑组件
UserBean.java

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package com.baosight.bean;
 
import com.baosight.util.GenerateUUID;
 
/**
 * <p>Title:UserBean </p>
 * <p>Description:TODO </p>
 * <p>Company: </p>
 * @author yuan
 * @date 2016-5-22 下午1:05:00*/
public class UserBean {
 //登录验证
 public boolean valid(String username,String password){
  boolean isValid = false;
  DBAcess db = new DBAcess();
  if(db.createConn()){
   String sql = "select * from p_user where username='"+username+"' and password='"+password+"'";
   db.query(sql);
   if(db.next()){
    isValid = true;
   }
   db.closeRs();
   db.closeStm();
   db.closeConn();
  }
  return isValid;
 }
 //注册验证
 public boolean isExist(String username){
  boolean isValid = false;
  DBAcess db = new DBAcess();
  if(db.createConn()){
   String sql = "select * from p_user where username='"+username+"'";
   db.query(sql);
   if(db.next()){
    isValid = true;
   }
   db.closeRs();
   db.closeStm();
   db.closeConn();
  }
  return isValid;
 }
 //注册用户
 public boolean add(String username,String password,String email){
  boolean isValid = false;
  DBAcess db = new DBAcess();
  if(db.createConn()){
   String sql = "insert into p_user(id,username,password,email) values('"+GenerateUUID.next()+"','"+username+"','"+password+"','"+email+"')";
   isValid = db.update(sql);
   db.closeStm();
   db.closeConn();
  }
  return isValid;
 }
}

上述业务逻辑javabean,定义了登录验证、注册验证和新增用户等方法

3.3关于生成唯一ID
上面在新增用户时需要插入ID,本例使用UUID来生成唯一ID

GenerateUUID.java

 

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package com.baosight.util;
 
import java.util.Date;
 
/**
 * <p>Title:GenerateUUID </p>
 * <p>Description:TODO </p>
 * <p>Company: </p>
 * @author yuan
 * @date 2016-5-22 下午1:31:46*/
public class GenerateUUID {
  private static Date date = new Date();
// private static StringBuilder buf = new StringBuilder();
  private static int seq = 0;
  private static final int ROTATION = 99999;
  public static synchronized long next(){
  if (seq > ROTATION) seq = 0;
//  buf.delete(0, buf.length());
  date.setTime(System.currentTimeMillis());
  String str = String.format("%1$tY%1$tm%1$td%1$tk%1$tM%1$tS%2$05d", date, seq++);
  return Long.parseLong(str);
 }
  public static void main(String[] args) {
   for(int i=0;i<100;i++){
    System.out.println(next());
   }
 }
}

4.页面编写
4.1登录页面
login.jsp

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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
 <base href="<%=basePath%>">
  
 <title>登录页面</title>
  
 <meta http-equiv="pragma" content="no-cache">
 <meta http-equiv="cache-control" content="no-cache">
 <meta http-equiv="expires" content="0"
 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
 <meta http-equiv="description" content="This is my page">
 <!--
 <link rel="stylesheet" type="text/css" href="styles.css">
 -->
 </head>
 
 <body>
 <form action="login_action.jsp" method="post">
  <table>
   <tr>
    <td colspan="2">登录窗口</td>
   </tr>
   <tr>
    <td>用户名:</td>
    <td><input type="text" name="username" />
    </td>
   </tr>
   <tr>
    <td>密码:</td>
    <td><input type="text" name="password" />
    </td>
   </tr>
   <tr>
    <td colspan="2"><input type="submit" value="登录" /> <a href="register.jsp">注册</a>
    </td>
   </tr>
  </table>
 </form>
</body>
</html>

页面效果

Java组件javabean用户登录实例详解

4.2登录业务逻辑处理页面
login_action.jsp

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<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page import="java.sql.*" %>
<%@ page import="com.baosight.bean.*" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
 
 <%
 String username = request.getParameter("username");
 String password = request.getParameter("password");
 if(username==null||"".equals(username.trim())||password==null||"".equals(password.trim())){
  //out.write("用户名或密码不能为空!");
  System.out.println("用户名或密码不能为空!");
  response.sendRedirect("login.jsp");
  return;
  //request.getRequestDispatcher("login.jsp").forward(request, response);
 }
 UserBean userBean = new UserBean();
 boolean isValid = userBean.valid(username,password);
 if(isValid){
  System.out.println("登录成功!");
  session.setAttribute("username", username);
  response.sendRedirect("welcome.jsp");
  return;
 }else{
  System.out.println("用户名或密码错误,登录失败!");
  response.sendRedirect("login.jsp");
  return;
 }
 %>

上面的JSP调用了Javabean进行业务处理
当用户名或密码为空时返回登录页面login.jsp

当登录成功后将用户信息保存到session,跳转到欢迎页面welcome.jsp

当登录失败时返回登录页面login.jsp

4.3登录成功欢迎页面
welcome.jsp

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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
 <base href="<%=basePath%>">
  
 <title>My JSP 'welcom.jsp' starting page</title>
  
 <meta http-equiv="pragma" content="no-cache">
 <meta http-equiv="cache-control" content="no-cache">
 <meta http-equiv="expires" content="0"
 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
 <meta http-equiv="description" content="This is my page">
 <!--
 <link rel="stylesheet" type="text/css" href="styles.css">
 -->
 </head>
 
 <body>
 <table>
  <tr>
   <td><img src="images/logo4.png" />
   </td>
   <td><img src="images/logo2.png" height="90" />
   </td>
  </tr>
  <tr>
   <td colspan="2"><hr />
   </td>
  </tr>
  <tr>
   <td>
    <table>
     <tr>
      <td><a>Main</a>
      </td>
     </tr>
     <tr>
      <td><a>Menu1</a>
      </td>
     </tr>
     <tr>
      <td><a>Menu2</a>
      </td>
     </tr>
     <tr>
      <td><a>Menu3</a>
      </td>
     </tr>
     <tr>
      <td><a>Menu4</a>
      </td>
     </tr>
     <tr>
      <td><a>Menu5</a>
      </td>
     </tr>
     <tr>
      <td><a>Menu6</a>
      </td>
     </tr>
     <tr>
      <td><a>Menu7</a>
      </td>
     </tr>
     <tr>
      <td><a>Menu8</a>
      </td>
     </tr>
    </table></td>
   <td>
    <form action="loginout.jsp" method="post">
     <table>
      <tr>
       <td colspan="2">登录成功!</td>
      </tr>
      <tr>
       <td>欢迎你,</td>
       <td>${username }</td>
      </tr>
      <tr>
       <td colspan="2"><input type="submit" value="退出" /></td>
      </tr>
     </table>
    </form></td>
  </tr>
 </table>
</body>
</html>

页面效果

Java组件javabean用户登录实例详解

4.4退出登录业务处理页面
loginout.jsp

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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
 <base href="<%=basePath%>">
  
 <title>My JSP 'loginout.jsp' starting page</title>
  
 <meta http-equiv="pragma" content="no-cache">
 <meta http-equiv="cache-control" content="no-cache">
 <meta http-equiv="expires" content="0"
 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
 <meta http-equiv="description" content="This is my page">
 <!--
 <link rel="stylesheet" type="text/css" href="styles.css">
 -->
 
 </head>
 
 <body>
 <%
 session.removeAttribute("username");
 response.sendRedirect("login.jsp");
 %>
 </body>
</html>

从session中移除用户信息,跳转到登录页面login.jsp

4.5用户注册页面
register.jsp

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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
 <base href="<%=basePath%>">
  
 <title>注册页面</title>
  
 <meta http-equiv="pragma" content="no-cache">
 <meta http-equiv="cache-control" content="no-cache">
 <meta http-equiv="expires" content="0"
 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
 <meta http-equiv="description" content="This is my page">
 <!--
 <link rel="stylesheet" type="text/css" href="styles.css">
 -->
 </head>
 
 <body>
 <form action="register_action.jsp" method="post">
  <table>
   <tr>
    <td colspan="2">注册窗口</td>
   </tr>
   <tr>
    <td>用户名:</td>
    <td><input type="text" name="username" /></td>
   </tr>
   <tr>
    <td>密码:</td>
    <td><input type="text" name="password1" /></td>
   </tr>
   <tr>
    <td>确认密码:</td>
    <td><input type="text" name="password2" /></td>
   </tr>
   <tr>
    <td>email:</td>
    <td><input type="text" name="email" /></td>
   </tr>
   <tr>
    <td colspan="2"><input type="submit" value="注册" /> <a href="login.jsp">返回</a></td>
   </tr>
  </table>
 </form>
</body>
</html>

运行效果

Java组件javabean用户登录实例详解

4.6注册业务处理页面

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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ page import="java.sql.*" %>
<%@ page import="com.baosight.bean.*" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
 
 
 <%
 String username = request.getParameter("username");
 String password1 = request.getParameter("password1");
 String password2 = request.getParameter("password2");
 String email = request.getParameter("email");
 if(username==null||"".equals(username.trim())||password1==null||"".equals(password1.trim())||password2==null||"".equals(password2.trim())||!password1.equals(password2)){
  //out.write("用户名或密码不能为空!");
  System.out.println("用户名或密码不能为空!");
  response.sendRedirect("register.jsp");
  return;
  //request.getRequestDispatcher("login.jsp").forward(request, response);
 }
 UserBean userBean = new UserBean();
 boolean isExit = userBean.isExist(username);
 if(!isExit){
  userBean.add(username, password1, email);
  System.out.println("注册成功,请登录!");
  response.sendRedirect("login.jsp");
  return;
 }else{
  System.out.println("用户名已存在!");
  response.sendRedirect("register.jsp");
  return;
 }
 %>

上面的JSP调用了Javabean进行业务处理

当用户名或密码为空时返回注册页面register.jsp

当注册用户名在数据库不存在时,新增用户

新增成功后跳转到登录页面login.jsp

当注册用户名在数据库存在时,返回注册页面register.jsp

5.总结

本例使用javabean对数据库操作和业务逻辑处理进行了封装。

以上即为使用javabean实现用户登录的简单介绍,还需要不断完善,希望大家一起学习进步!

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