用JavaEE写一个新闻管理系统

好的，以下是 JavaEE 新闻管理系统的代码示例：

1. 创建数据库表

首先需要创建一个新闻表，包括新闻ID、新闻标题、新闻内容、发布时间、修改时间等字段。

CREATE TABLE `news` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(255) NOT NULL,
  `content` text NOT NULL,
  `create_time` datetime NOT NULL,
  `update_time` datetime NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4;

2. 创建 Java 类

在 JavaEE 项目中，我们可以使用 Servlet 和 JSP 进行开发。首先创建一个 News 类，用于封装新闻信息。

public class News {
    private int id;
    private String title;
    private String content;
    private Date createTime;
    private Date updateTime;
    // 省略 getter 和 setter 方法
}

3. 创建 DAO 类

创建一个 NewsDAO 类，用于与数据库进行交互，实现增删改查等操作。

public class NewsDAO {
    private Connection conn;

    public NewsDAO(Connection conn) {
        this.conn = conn;
    }

    // 添加新闻
    public void addNews(News news) throws SQLException {
        PreparedStatement pstmt = null;
        String sql = "INSERT INTO news (title, content, create_time, update_time) VALUES (?, ?, ?, ?)";
        try {
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, news.getTitle());
            pstmt.setString(2, news.getContent());
            pstmt.setTimestamp(3, new Timestamp(news.getCreateTime().getTime()));
            pstmt.setTimestamp(4, new Timestamp(news.getUpdateTime().getTime()));
            pstmt.executeUpdate();
        } finally {
            if (pstmt != null) {
                pstmt.close();
            }
        }
    }

    // 修改新闻
    public void updateNews(News news) throws SQLException {
        PreparedStatement pstmt = null;
        String sql = "UPDATE news SET title=?, content=?, update_time=? WHERE id=?";
        try {
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, news.getTitle());
            pstmt.setString(2, news.getContent());
            pstmt.setTimestamp(3, new Timestamp(news.getUpdateTime().getTime()));
            pstmt.setInt(4, news.getId());
            pstmt.executeUpdate();
        } finally {
            if (pstmt != null) {
                pstmt.close();
            }
        }
    }

    // 删除新闻
    public void deleteNews(int id) throws SQLException {
        PreparedStatement pstmt = null;
        String sql = "DELETE FROM news WHERE id=?";
        try {
            pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);
            pstmt.executeUpdate();
        } finally {
            if (pstmt != null) {
                pstmt.close();
            }
        }
    }

    // 根据ID获取新闻
    public News getNewsById(int id) throws SQLException {
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        String sql = "SELECT * FROM news WHERE id=?";
        try {
            pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);
            rs = pstmt.executeQuery();
            if (rs.next()) {
                News news = new News();
                news.setId(rs.getInt("id"));
                news.setTitle(rs.getString("title"));
                news.setContent(rs.getString("content"));
                news.setCreateTime(rs.getTimestamp("create_time"));
                news.setUpdateTime(rs.getTimestamp("update_time"));
                return news;
            } else {
                return null;
            }
        } finally {
            if (rs != null) {
                rs.close();
            }
            if (pstmt != null) {
                pstmt.close();
            }
        }
    }

    // 获取所有新闻
    public List<News> getAllNews() throws SQLException {
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        String sql = "SELECT * FROM news";
        try {
            pstmt = conn.prepareStatement(sql);
            rs = pstmt.executeQuery();
            List<News> newsList = new ArrayList<>();
            while (rs.next()) {
                News news = new News();
                news.setId(rs.getInt("id"));
                news.setTitle(rs.getString("title"));
                news.setContent(rs.getString("content"));
                news.setCreateTime(rs.getTimestamp("create_time"));
                news.setUpdateTime(rs.getTimestamp("update_time"));
                newsList.add(news);
            }
            return newsList;
        } finally {
            if (rs != null) {
                rs.close();
            }
            if (pstmt != null) {
                pstmt.close();
            }
        }
    }
}

4. 创建 Servlet 类

创建一个 NewsServlet 类，用于接收用户请求，调用 NewsDAO 类中的方法进行处理，并将结果返回给用户。

@WebServlet(name = "NewsServlet", urlPatterns = {"/news"})
public class NewsServlet extends HttpServlet {
    private Connection conn;

    public void init() throws ServletException {
        // 获取数据库连接
        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8";
            String username = "root";
            String password = "root";
            conn = DriverManager.getConnection(url, username, password);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void destroy() {
        // 关闭数据库连接
        try {
            if (conn != null) {
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String action = request.getParameter("action");
        if ("add".equals(action)) {
            addNews(request, response);
        } else if ("update".equals(action)) {
            updateNews(request, response);
        } else if ("delete".equals(action)) {
            deleteNews(request, response);
        } else if ("view".equals(action)) {
            viewNews(request, response);
        } else {
            listNews(request, response);
        }
    }

    // 添加新闻
    private void addNews(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String title = request.getParameter("title");
        String content = request.getParameter("content");
        Date createTime = new Date();
        Date updateTime = new Date();
        News news = new News();
        news.setTitle(title);
        news.setContent(content);
        news.setCreateTime(createTime);
        news.setUpdateTime(updateTime);
        NewsDAO newsDAO = new NewsDAO(conn);
        try {
            newsDAO.addNews(news);
            response.sendRedirect(request.getContextPath() + "/news");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    // 修改新闻
    private void updateNews(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        String title = request.getParameter("title");
        String content = request.getParameter("content");
        Date updateTime = new Date();
        News news = new News();
        news.setId(id);
        news.setTitle(title);
        news.setContent(content);
        news.setUpdateTime(updateTime);
        NewsDAO newsDAO = new NewsDAO(conn);
        try {
            newsDAO.updateNews(news);
            response.sendRedirect(request.getContextPath() + "/news");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    // 删除新闻
    private void deleteNews(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        NewsDAO newsDAO = new NewsDAO(conn);
        try {
            newsDAO.deleteNews(id);
            response.sendRedirect(request.getContextPath() + "/news");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    // 查看新闻
    private void viewNews(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int id = Integer.parseInt(request.getParameter("id"));
        NewsDAO newsDAO = new NewsDAO(conn);
        try {
            News news = newsDAO.getNewsById(id);
            request.setAttribute("news", news);
            request.getRequestDispatcher("/view.jsp").forward(request, response);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    // 列出所有新闻
    private void listNews(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        NewsDAO newsDAO = new NewsDAO(conn);
        try {
            List<News> newsList = newsDAO.getAllNews();
            request.setAttribute("newsList", newsList);
            request.getRequestDispatcher("/list.jsp").forward(request, response);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

5. 创建 JSP 页面

创建两个 JSP 页面，list.jsp 用于展示所有新闻，view.jsp 用于展示单个新闻的详细信息。

list.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>新闻管理系统</title>
</head>
<body>
    <h1>新闻列表</h1>
    <p><a href="${request.contextPath}/news?action=add">添加新闻</a></p>
    <table border="1">
        <tr>
            <th>ID</th>
            <th>标题</th>
            <th>创建时间</th>
            <th>修改时间</th>
            <th>操作</th>
        </tr>
        <c:forEach items="${newsList}" var="news">
            <tr>
                <td>${news.id}</td>
                <td>${news.title}</td>
                <td>${news.createTime}</td>
                <td>${news.updateTime}</td>
                <td>
                    <a href="${request.contextPath}/news?action=view&id=${news.id}">查看</a>
                    <a href="${request.contextPath}/news?action=update&id=${news.id}">编辑</a>
                    <a href="${request.contextPath}/news?action=delete&id=${news.id}" onclick="return confirm('确定删除该新闻吗？')">删除</a>
                </td>
            </tr>
        </c:forEach>
    </table>
</body>
</html>

view.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>新闻管理系统</title>
</head>
<body>
    <h1>${news.title}</h1>
    <p>${news.content}</p>
    <p>
        <a href="${request.contextPath}/news?action=update&id=${news.id}">编辑</a>
        <a href="${request.contextPath}/news?action=delete&id=${news.id}" onclick="return confirm('确定删除该新闻吗？')">删除</a>
    </p>
</body>
</html>

6. 部署项目

将代码打成 WAR 包，部署到 Tomcat 或其他 JavaEE 容器中即可。访问 http://localhost:8080/news 即可查看新闻列表。

以上就是一个简单的 JavaEE 新闻管理系统的实现，仅供参考。