javaweb写一个学生管理系统

以下是一个简单的JavaWeb学生信息管理系统的实现，包括学生信息的增删改查功能：

1. 首先创建一个名为Student的JavaBean类，用于存储学生信息，包括学号、姓名、性别、年龄等属性。

public class Student {
    private String id;
    private String name;
    private String gender;
    private int age;

    // 构造方法、getter和setter方法省略
}

2. 创建一个名为StudentDao的数据访问对象类，用于对学生信息进行增删改查操作。这里使用了JDBC连接数据库进行操作。

public class StudentDao {
    // 数据库连接信息
    private static final String URL = "jdbc:mysql://localhost:3306/student";
    private static final String USERNAME = "root";
    private static final String PASSWORD = "123456";

    // 添加学生信息
    public void addStudent(Student student) {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            // 加载数据库驱动
            Class.forName("com.mysql.jdbc.Driver");
            // 获取数据库连接
            conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
            // 定义SQL语句
            String sql = "INSERT INTO student(id, name, gender, age) VALUES(?, ?, ?, ?)";
            // 创建PreparedStatement对象
            pstmt = conn.prepareStatement(sql);
            // 设置参数
            pstmt.setString(1, student.getId());
            pstmt.setString(2, student.getName());
            pstmt.setString(3, student.getGender());
            pstmt.setInt(4, student.getAge());
            // 执行SQL语句
            pstmt.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 关闭数据库连接
            try {
                if (pstmt != null) {
                    pstmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    // 删除学生信息
    public void deleteStudent(String id) {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            // 加载数据库驱动
            Class.forName("com.mysql.jdbc.Driver");
            // 获取数据库连接
            conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
            // 定义SQL语句
            String sql = "DELETE FROM student WHERE id=?";
            // 创建PreparedStatement对象
            pstmt = conn.prepareStatement(sql);
            // 设置参数
            pstmt.setString(1, id);
            // 执行SQL语句
            pstmt.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 关闭数据库连接
            try {
                if (pstmt != null) {
                    pstmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    // 修改学生信息
    public void updateStudent(Student student) {
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            // 加载数据库驱动
            Class.forName("com.mysql.jdbc.Driver");
            // 获取数据库连接
            conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
            // 定义SQL语句
            String sql = "UPDATE student SET name=?, gender=?, age=? WHERE id=?";
            // 创建PreparedStatement对象
            pstmt = conn.prepareStatement(sql);
            // 设置参数
            pstmt.setString(1, student.getName());
            pstmt.setString(2, student.getGender());
            pstmt.setInt(3, student.getAge());
            pstmt.setString(4, student.getId());
            // 执行SQL语句
            pstmt.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 关闭数据库连接
            try {
                if (pstmt != null) {
                    pstmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    // 查询学生信息
    public List<Student> queryStudent() {
        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        List<Student> list = new ArrayList<Student>();
        try {
            // 加载数据库驱动
            Class.forName("com.mysql.jdbc.Driver");
            // 获取数据库连接
            conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
            // 定义SQL语句
            String sql = "SELECT * FROM student";
            // 创建PreparedStatement对象
            pstmt = conn.prepareStatement(sql);
            // 执行SQL语句
            rs = pstmt.executeQuery();
            // 处理结果集
            while (rs.next()) {
                Student student = new Student();
                student.setId(rs.getString("id"));
                student.setName(rs.getString("name"));
                student.setGender(rs.getString("gender"));
                student.setAge(rs.getInt("age"));
                list.add(student);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 关闭数据库连接
            try {
                if (rs != null) {
                    rs.close();
                }
                if (pstmt != null) {
                    pstmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return list;
    }
}

3. 创建一个名为StudentServlet的Servlet类，用于处理学生信息管理系统的请求。这里使用了JSP页面进行展示。

public class StudentServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

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

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 设置请求编码和响应编码
        request.setCharacterEncoding("UTF-8");
        response.setContentType("text/html;charset=UTF-8");

        // 获取操作类型
        String type = request.getParameter("type");

        // 根据操作类型进行相应的操作
        if ("add".equals(type)) {
            addStudent(request, response);
        } else if ("delete".equals(type)) {
            deleteStudent(request, response);
        } else if ("update".equals(type)) {
            updateStudent(request, response);
        } else if ("query".equals(type)) {
            queryStudent(request, response);
        }
    }

    // 添加学生信息
    private void addStudent(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 获取学生信息
        String id = request.getParameter("id");
        String name = request.getParameter("name");
        String gender = request.getParameter("gender");
        int age = Integer.parseInt(request.getParameter("age"));
        Student student = new Student(id, name, gender, age);

        // 调用数据访问对象添加学生信息
        StudentDao dao = new StudentDao();
        dao.addStudent(student);

        // 跳转到查询学生信息页面
        response.sendRedirect("query.jsp");
    }

    // 删除学生信息
    private void deleteStudent(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 获取学生学号
        String id = request.getParameter("id");

        // 调用数据访问对象删除学生信息
        StudentDao dao = new StudentDao();
        dao.deleteStudent(id);

        // 跳转到查询学生信息页面
        response.sendRedirect("query.jsp");
    }

    // 修改学生信息
    private void updateStudent(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 获取学生信息
        String id = request.getParameter("id");
        String name = request.getParameter("name");
        String gender = request.getParameter("gender");
        int age = Integer.parseInt(request.getParameter("age"));
        Student student = new Student(id, name, gender, age);

        // 调用数据访问对象修改学生信息
        StudentDao dao = new StudentDao();
        dao.updateStudent(student);

        // 跳转到查询学生信息页面
        response.sendRedirect("query.jsp");
    }

    // 查询学生信息
    private void queryStudent(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 调用数据访问对象查询学生信息
        StudentDao dao = new StudentDao();
        List<Student> list = dao.queryStudent();

        // 将查询结果存储到request对象中
        request.setAttribute("list", list);

        // 转发到查询学生信息页面
        request.getRequestDispatcher("query.jsp").forward(request, response);
    }
}

4. 创建一个名为add.jsp的JSP页面，用于添加学生信息。

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>添加学生信息</title>
</head>
<body>
    <h1>添加学生信息</h1>
    <form action="StudentServlet" method="post">
        <input type="hidden" name="type" value="add">
        学号：<input type="text" name="id"><br>
        姓名：<input type="text" name="name"><br>
        性别：<input type="radio" name="gender" value="男">男
             <input type="radio" name="gender" value="女">女<br>
        年龄：<input type="text" name="age"><br>
        <input type="submit" value="添加">
    </form>
</body>
</html>

5. 创建一个名为query.jsp的JSP页面，用于查询学生信息。

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>查询学生信息</title>
</head>
<body>
    <h1>查询学生信息</h1>
    <table border="1">
        <tr>
            <th>学号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>操作</th>
        </tr>
        <c:forEach items="${list}" var="student">
            <tr>
                <td>${student.id}</td>
                <td>${student.name}</td>
                <td>${student.gender}</td>
                <td>${student.age}</td>
                <td>
                    <a href="update.jsp?id=${student.id}&name=${student.name}&gender=${student.gender}&age=${student.age}">修改</a>
                    <a href="StudentServlet?type=delete&id=${student.id}">删除</a>
                </td>
            </tr>
        </c:forEach>
    </table>
    <br>
    <a href="add.jsp">添加学生信息</a>
</body>
</html>

6. 创建一个名为update.jsp的JSP页面，用于修改学生信息。

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>修改学生信息</title>
</head>
<body>
    <h1>修改学生信息</h1>
    <form action="StudentServlet" method="post">
        <input type="hidden" name="type" value="update">
        学号：<input type="text" name="id" value="${param.id}" readonly><br>
        姓名：<input type="text" name="name" value="${param.name}"><br>
        性别：<input type="radio" name="gender" value="男" <c:if test="${param.gender=='男'}">checked</c:if>>男
             <input type="radio" name="gender" value="女" <c:if test="${param.gender=='女'}">checked</c:if>>女<br>
        年龄：<input type="text" name="age" value="${param.age}"><br>
        <input type="submit" value="修改">
    </form>
</body>
</html>

以上就是一个简单的JavaWeb学生信息管理系统的实现。可以根据实际需求进行扩展和优化。