問題與思考6
網絡系統都需要哪些技術：
JSP基礎，JSP動作指令，JavaBean, JDBC, 表達試語言，國際化、標準標簽庫，MVC模式，數據庫鏈接
JSP用於顯示，servlet用於控制，JSP主要完成與用戶的交互過程，不應該包括處理代碼和控制代碼
課堂測試代碼：
package com.jaovo.msg.dao;
import java.util.List;
import com.jaovo.msg.model.User;
public interface IUserDao {
public void add(User user);
public void delete(int id);
public void update(User user);
public User load(int id);
public User load(String username);
public List<User> load();
}
package com.jaovo.msg.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import com.jaovo.msg.Util.DBUtil;
import com.jaovo.msg.Util.UserException;
import com.jaovo.msg.model.User;
//import sun.net.www.content.text.plain;
public class UserDaoImpl implements IUserDao {
@Override
public void add(User user) {
//鑾峰緱閾炬帴瀵矽薄
Connection connection = DBUtil.getConnection();
//鍑嗗sql璇彞
String sql = "select count(*) from t_user where username = ?";
//鍒涘緩璇彞浼犺緭瀵矽薄
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
try {
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, user.getUsername());
//鎺ユ敹緇撴灉闆?
resultSet = preparedStatement.executeQuery();
//閬嶅巻緇撴灉闆?
while(resultSet.next()) {
if (resultSet.getInt(1) > 0) {
throw new UserException("用戶已經存在") ;
}
}
sql = "insert into t_user(username,password,nickname) value (?,?,?)";
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, user.getUsername());
preparedStatement.setString(2, user.getPassword());
preparedStatement.setString(3, user.getNickname());
preparedStatement.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
//鍏抽棴璧勬簮
DBUtil.close(resultSet);
DBUtil.close(preparedStatement);
DBUtil.close(connection);
}
}
@Override
public void delete(int id) {
Connection connection = DBUtil.getConnection();
String sql = "delete from t_user where id = ?";
PreparedStatement preparedStatement = null;
try {
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setInt(1, id);
preparedStatement.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
DBUtil.close(preparedStatement);
DBUtil.close(connection);
}
}
@Override
public void update(User user) {
Connection connection = DBUtil.getConnection();
//鍑嗗sql璇彞
String sql = "update t_user set password = ? , nickname=? where id = ?";
//鍒涘緩璇彞浼犺緭瀵矽薄
PreparedStatement preparedStatement = null;
try {
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, user.getPassword());
preparedStatement.setString(2, user.getNickname());
preparedStatement.setInt(3, user.getId());
preparedStatement.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
DBUtil.close(preparedStatement);
DBUtil.close(connection);
}
}
@Override
public User load(int id) {
Connection connection = DBUtil.getConnection();
//鍑嗗sql璇彞
String sql = "select * from t_user where id = ?";
//鍒涘緩璇彞浼犺緭瀵矽薄
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
User user = null;
try {
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setInt(1, id);
resultSet = preparedStatement.executeQuery();
while(resultSet.next()) {
user = new User();
user.setId(id);
user.setUsername(resultSet.getString("username"));
user.setPassword(resultSet.getString("password"));
user.setNickname(resultSet.getString("nickname"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
DBUtil.close(resultSet);
DBUtil.close(preparedStatement);
DBUtil.close(connection);
}
return user;
}
@Override
public User load(String username) {
// TODO Auto-generated method stub
return null;
}
@Override
public List<User> load() {
Connection connection = DBUtil.getConnection();
//鍑嗗sql璇彞
String sql = "select * from t_user ";
//鍒涘緩璇彞浼犺緭瀵矽薄
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
//闆嗗悎涓彧鑳芥斁鍏ser瀵矽薄
List<User> users = new ArrayList<User>();
User user = null;
try {
preparedStatement = connection.prepareStatement(sql);
resultSet = preparedStatement.executeQuery();
while(resultSet.next()) {
user = new User();
user.setId(resultSet.getInt("id"));
user.setUsername(resultSet.getString("username"));
user.setPassword(resultSet.getString("password"));
user.setNickname(resultSet.getString("nickname"));
users.add(user);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
DBUtil.close(resultSet);
DBUtil.close(preparedStatement);
DBUtil.close(connection);
}
return users;
}
}
package com.jaovo.msg.model;
public class User {
private int id;
private String username;
private String nickname;
private String password;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getNickname() {
return nickname;
}
public void setNickname(String nickname) {
this.nickname = nickname;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
package com.jaovo.msg.Util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class DBUtil {
public static Connection getConnection() {
try {
//1 鍔犺澆椹卞姩
Class.forName("com.mysql.jdbc.Driver").newInstance();
} catch (InstantiationException | IllegalAccessException | ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String user = "root";
String password = "LQYroot";
String url = "jdbc:mysql://localhost:3306/jaovo_msg";
Connection connection = null;
try {
//2 鍒涘緩閾炬帴瀵矽薄connection
connection = DriverManager.getConnection(url,user,password);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return connection;
}
//鍏抽棴璧勬簮鐨勬柟娉?
public static void close(Connection connection ) {
try {
if (connection != null) {
connection.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void close(PreparedStatement preparedStatement ) {
try {
if (preparedStatement != null) {
preparedStatement.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void close(ResultSet resultSet ) {
try {
if (resultSet != null) {
resultSet.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
package com.jaovo.msg.Util;
public class UserException extends RuntimeException{
/**
*
*/
private static final long serialVersionUID = 1L;
public UserException() {
super();
// TODO Auto-generated constructor stub
}
public UserException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
super(message, cause, enableSuppression, writableStackTrace);
// TODO Auto-generated constructor stub
}
public UserException(String message, Throwable cause) {
super(message, cause);
// TODO Auto-generated constructor stub
}
public UserException(String message) {
super(message);
// TODO Auto-generated constructor stub
}
public UserException(Throwable cause) {
super(cause);
// TODO Auto-generated constructor stub
}
}
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en">
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="http://code.jquery.com/mobile/1.3.2/jquery.mobile-1.3.2.min.css">
<script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
<script src="http://code.jquery.com/mobile/1.3.2/jquery.mobile-1.3.2.min.js"></script>
<title>用戶添加頁面</title>
<style type="test/css">.box{
width:700 px;
height:352 px;
margin:0 auto;
backgrand:url(bbb.PNG)) no-repeat center;
}</style>
</head>
<body>
<div class="box"></div>
<%=request.getAttribute("error") %>
<form action="add.jsp" method="get">
<table align="center" border="1" width="500">
<tr>
<td>用戶名稱 :</td>
<td>
<input type="text" name="username" />
</td>
</tr>
<tr>
<td>用戶密碼:</td>
<td>
<input type="password" name="password" />
</td>
</tr>
<tr>
</tr>
<tr align="center">
<td colspan="2">
<input type="submit" value="登錄" />
</td>
</tr>
</table>
</form>
</body>
</html>
<%@page import="com.jaovo.msg.Util.UserException"%>
<%@page import="com.jaovo.msg.dao.UserDaoImpl"%>
<%@page import="com.jaovo.msg.model.User"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<%
//接收客戶端傳遞過來的參數
String username = request.getParameter("username");
String password = request.getParameter("password");
String nickname = request.getParameter("nickname");
if(username == null || "".equals(username.trim())){
request.setAttribute("error", "用戶名不能為空");
%>
<jsp:forward page="addInput.jsp"></jsp:forward>
<%
}
User user = new User();
user.setUsername(username);
user.setPassword(password);
user.setNickname(nickname);
UserDaoImpl userDao = new UserDaoImpl();
try{
//UserDaoImpl userDao = new UserDaoImpl();
userDao.add(user);
//重定向
%>
<%
}catch(UserException e){
%>
<h2 style="color:red ; font-size:50px">發生錯誤 : <%=e.getMessage() %></h2>
<%
}
%>
</html>
運行截圖：
說明課堂測試未按時完成的原因：
沒有提前學習數據庫方面的知識，上課時沒有認真記筆記，記錄eclipse的配置方法，課下也沒有認真學習JSp方面的知識，總的來說自主學習能力不足。
對這門課的希望和目標;
實踐中學習，實踐中總結，鍛煉獨立解決問題的能力，勤於總結，善於合作，積極學習。
計劃每周有25小時的學習該門課程的時間。
問題與思考6