Java组件javabean用户登录实例详解
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2024-03-12 11:52:14
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jav...
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
2.2页面流程图
2.3系统架构图
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
-- 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
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
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
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
<%@ 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
4.2登录业务逻辑处理页面
login_action.jsp
<%@ 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
<%@ 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
4.4退出登录业务处理页面
loginout.jsp
<%@ 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
<%@ 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
4.6注册业务处理页面
<%@ 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！