我最近在学习javaweb |21xrx.com

我最近在学习javaweb

2023-06-15 07:42:15 深夜i -- --

javaweb 简单管理系统代码

我最近在学习javaweb，尝试着写了一个简单的管理系统。这个管理系统仅有几个基础功能，但也可以帮助我更好地理解Java语言的运用。今天我想和大家分享一下这个系统的关键代码。

首先，我在Eclipse中创建了一个动态Web项目。在这个项目中，我新建了三个Java类：User（用户）、Product（产品）和DBUtil（数据库工具类）。User和Product都继承了一个Base类，该类提供了关于ID和Name的公共属性。

以下是我的User和Product类：


public class User extends Base {
  private String password;
  private String email;
  public String getPassword()
    return password;
  
  public void setPassword(String password)
    this.password = password;
  
  public String getEmail()
    return email;
  
  public void setEmail(String email)
    this.email = email;
  
}


public class Product extends Base {
  private String description;
  private int price;
  public String getDescription()
    return description;
  
  public void setDescription(String description)
    this.description = description;
  
  public int getPrice()
    return price;
  
  public void setPrice(int price)
    this.price = price;
  
}

我使用了MySQL数据库来存储数据，所以我创建了一个DBUtil类，来建立与数据库的连接以及执行SQL语句。以下是我的DBUtil类：


public class DBUtil {
  // 数据库连接
  public static Connection getConnection() {
    String url = "jdbc:mysql://localhost:3306/test";
    String username = "root";
    String password = "password";
    try {
      Class.forName("com.mysql.jdbc.Driver");
      Connection conn = DriverManager.getConnection(url, username, password);
      return conn;
    } catch (ClassNotFoundException | SQLException e) {
      e.printStackTrace();
    }
    return null;
  }
  // 执行查询语句
  public static ResultSet executeQuery(String sql) {
    try {
      Connection conn = getConnection();
      Statement stmt = conn.createStatement();
      ResultSet rs = stmt.executeQuery(sql);
      return rs;
    } catch (SQLException e) {
      e.printStackTrace();
    }
    return null;
  }
  // 执行更新语句
  public static boolean executeUpdate(String sql) {
    try {
      Connection conn = getConnection();
      Statement stmt = conn.createStatement();
      int count = stmt.executeUpdate(sql);
      return count > 0;
    } catch (SQLException e) {
      e.printStackTrace();
    }
    return false;
  }
}

在这个简单的管理系统中，我只实现了两个基本功能：用户的新增和产品的查询。在我的Servlet类中，我实现了对用户和产品的增加和查找操作。以下是我的Servlet类：


public class UserServlet extends HttpServlet {
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    doPost(request, response);
  }
  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    request.setCharacterEncoding("UTF-8");
    response.setCharacterEncoding("UTF-8");
    String method = request.getParameter("method");
    if("add".equals(method)) {
      addUser(request, response);
    }
  }
  private void addUser(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    User user = new User();
    user.setName(request.getParameter("name"));
    user.setPassword(request.getParameter("password"));
    user.setEmail(request.getParameter("email"));
    boolean result = DBUtil.executeUpdate("insert into user(name,password,email) values('"+user.getName()+"','"+user.getPassword()+"','"+user.getEmail()+"')");
    if(result) {
      request.getRequestDispatcher("/success.jsp").forward(request, response);
    } else {
      request.getRequestDispatcher("/fail.jsp").forward(request, response);
    }
  }
}
public class ProductServlet extends HttpServlet {
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    doPost(request, response);
  }
  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    request.setCharacterEncoding("UTF-8");
    response.setCharacterEncoding("UTF-8");
    String method = request.getParameter("method");
    if("search".equals(method)) {
      searchProduct(request, response);
    }
  }
  private void searchProduct(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    String searchName = request.getParameter("searchName");
    ResultSet rs = DBUtil.executeQuery("select * from product where name='"+searchName+"'");
    List
  list = new ArrayList<>();
 
    try {
      while(rs.next()) {
        Product product = new Product();
        product.setId(rs.getInt("id"));
        product.setName(rs.getString("name"));
        product.setDescription(rs.getString("description"));
        product.setPrice(rs.getInt("price"));
        list.add(product);
      }
      request.setAttribute("list", list);
      request.getRequestDispatcher("/product.jsp").forward(request, response);
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
}

使用Servlet在前端页面上实现了用户的新增和产品的查询，这两项业务相对简单，足够了解Java语言在javaweb中的运用，通过实例加深对Java的理解。

以上就是我写的javaweb简单管理系统的代码，虽然只是一个简单的小项目，但也让我收获了不少，希望对那些和我一样正在学习javaweb的初学者对javaweb有更深入的了解与学习。

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