java 在struts 1.3中如何从数据库中检索数据并使用DAO显示它
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时间：2020-10-31 17:08:20 来源:igfitidea点击:
In struts 1.3 how to retrieve data from database and display it using DAO
提问by sambot
*M new to struts. I am making simple login page that display username and password by retrieving it from database. I m using DAO. I have LoginDAO.java, LoginAction.java and Displaydata.jsp pages. *
* M 刚接触 struts。我正在制作简单的登录页面，通过从数据库中检索来显示用户名和密码。我正在使用 DAO。我有 LoginDAO.java、LoginAction.java 和 Displaydata.jsp 页面。*
LoginDAO.java
登录DAO.java
public boolean login(String user,String pass) throws SQLException
{
Connection con = getConnection();
Statement st;
try {
st = con.createStatement();
st.executeQuery("select * from login where Username='" + user + "' and Password='" + pass + "'");
return true;
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
return false;
}
LoginAction.java
登录操作.java
public class LoginAction extends Action
{
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
DynaValidatorForm rf= (DynaValidatorForm) form;
String username = rf.get("username").toString();
String password = rf.get("password").toString();
HttpSession session=request.getSession();
session.setAttribute("user", username);
Login dao= new Login();
if(dao.login(username,password))
{
System.out.println("GOT");
return mapping.findForward("success");}
else
{System.out.println("NOT");
return mapping.findForward("failure");
}
}
}
and also what do i write in Dislpaydata.jsp to display username and password in it dont want any java code in it. Thankyou
以及我在 Dislpaydata.jsp 中写什么来显示用户名和密码，不需要任何 Java 代码。谢谢
回答by Paul Vargas
Right. Some time ago I built an application with Struts 1.x and MySql with login.
对。前段时间我用 Struts 1.x 和 MySql 构建了一个带有登录的应用程序。
LoginAction
登录操作
public ActionForward login( ... ) throws Exception {
String forward;
final String mail = PropertyUtils.getProperty(form, "mail");
final String password = PropertyUtils.getProperty(form, "password");
if (LoginService.getInstance().validate(mail, password)) {
// Do something e.g. put name of user in session
forward = SUCCESS;
} else {
forward = ERROR;
}
return mapping.findForward(forward);
}
LoginService
登录服务
public boolean validate(final String mail, final String password)
throws ServiceException {
try {
final boolean valid;
// Validate null and empty
// Validate with DB
final UserDAO dao = new UserDAO();
final User user = dao.findByPk(mail);
if (user == null) {
valid = false;
} else {
if (password.equals(user.getPassword())) {
valid = true;
} else {
valid = false;
}
}
return valid;
} catch (DAOException e) {
throw new ServiceException("Error validating user and password.", e);
}
}
UserDAO
用户DAO
private static final String FIND_BY_PK_SQL
= "SELECT mail, name, password, admin FROM user WHERE mail = ?";
public User findByPk(final String mail) throws DAOException {
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
conn = getConnection();
ps = conn.prepareStatement(FIND_BY_PK_SQL);
ps.setString(1, mail); // PK, NOT NULL
rs = ps.executeQuery();
if (rs.next()) {
return fill(rs);
}
return null;
} catch (final SQLException e) {
throw new DAOException(e);
} finally {
// Close DB resources
}
}
private User fill(final ResultSet rs) throws SQLException {
final User user = new User();
user.setMail(rs.getString("mail"));
user.setName(rs.getString("name"));
user.setPassword(rs.getString("password"));
user.setAdmin(rs.getBoolean("admin"));
return user;
}
In my case I have a table userwith mailas a primary key. There are various forms.
在我来说，我有一个表user与mail作为主键。有多种形式。
More examples:
更多例子：
- Building a Login Application
- Struts Login Application Using Action Form Tutorial | DZone
- Creating a Email Login Web Application with Struts
e.g. For show the name of variable user in session scope from the database:
例如，从数据库中显示会话范围内变量用户的名称：
LoginAction
登录操作
if (LoginService.getInstance().validate(mail, password)) {
final HttpSession session = request.getSession();
final User user = UserService.getInstance().getUser(mail);
session.setAttribute("user", user);
forward = SUCCESS;
}
home.jsp
主页.jsp
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib uri="http://struts.apache.org/tags-bean" prefix="bean"%>
Welcome,
<bean:write scope="session" name="user" property="name" filter="false" />
回答by Louis Minh
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Login Page</title>
<script src="//code.jquery.com/jquery-1.11.3.min.js"></script>
<script type="text/javascript"
src="http://ajax.aspnetcdn.com/ajax/jquery.validate/1.13.1/jquery.validate.min.js"></script>
</head>
<body bgcolor="#2EFEF7">
<form action="action" method="post" id="formDemo" name="MyForm">
<div id="header">
<h2 style="color: red;">Training</h2>
</div>
<hr>
<h3>Login</h3>
<div id="center" style="padding-top: 50px; padding-bottom: 220px;">
<table align="center">
<tr>
<th colspan="2"><h1 style="color: BLUE;">LOGIN</h1></th>
</tr>
<tr>
<th colspan="2"><h5 id="error" style="color: red;"></h5></th>
</tr>
<tr>
<td>UserID:</td>
<td><input type="text" size="40" name="UserId" maxlength="8"></td>
</tr>
<tr>
<td>Password:</td>
<td><input type="text" size="40" name="Password" maxlength="8"></td>
</tr>
<tr>
<td colspan="2" align="center"><input type="submit"
value="Login"> <input type="button" id="reset"
value="Clear"></td>
</tr>
</table>
</div>
<hr>
<div id="footer">
<label>Copy right@ 2000-2008 FUJINET, All Rights Reserved.</label>
</div>
</form>
<script type="text/javascript">
<!--
// Form validation code will come here.
function validate() {
if (document.MyForm.UserId.value === ""
|| document.MyForm.UserId.value === null) {
document.getElementById("error").innerHTML = "Please insert userId";
return false;
}
if (document.MyForm.Password.value === ""
|| document.MyForm.Password.value === null) {
document.getElementById("error").innerHTML = "Please insert password";
return false;
}
return (true);
}
$("#reset").click(function(event) {
document.MyForm.UserId.value = "";
document.MyForm.Password.value = "";
document.getElementById("error").innerHTML = "";
});
$("#formDemo").submit(function(event){
return validate();
});
</script>
</body>
</html>