Java Web 学生信息管理系统：DAO、Model 和 Servlet 示例

以下是一个简单的学生信息管理系统的示例代码：\n\n1. DAO类（StudentDAO.java）：\n\njava\nimport java.util.ArrayList;\nimport java.util.List;\n\npublic class StudentDAO {\n private static List<Student> students = new ArrayList<>();\n\n public void addStudent(Student student) {\n students.add(student);\n }\n\n public void updateStudent(Student student) {\n for (int i = 0; i < students.size(); i++) {\n if (students.get(i).getId() == student.getId()) {\n students.set(i, student);\n break;\n }\n }\n }\n\n public void deleteStudent(int id) {\n for (int i = 0; i < students.size(); i++) {\n if (students.get(i).getId() == id) {\n students.remove(i);\n break;\n }\n }\n }\n\n public List<Student> getAllStudents() {\n return students;\n }\n\n public Student getStudentById(int id) {\n for (Student student : students) {\n if (student.getId() == id) {\n return student;\n }\n }\n return null;\n }\n}\n\n\n2. Model类（Student.java）：\n\njava\npublic class Student {\n private int id;\n private String name;\n private String grade;\n private String department;\n\n public Student(int id, String name, String grade, String department) {\n this.id = id;\n this.name = name;\n this.grade = grade;\n this.department = department;\n }\n\n // Getters and setters\n\n public int getId() {\n return id;\n }\n\n public void setId(int id) {\n this.id = id;\n }\n\n public String getName() {\n return name;\n }\n\n public void setName(String name) {\n this.name = name;\n }\n\n public String getGrade() {\n return grade;\n }\n\n public void setGrade(String grade) {\n this.grade = grade;\n }\n\n public String getDepartment() {\n return department;\n }\n\n public void setDepartment(String department) {\n this.department = department;\n }\n}\n\n\n3. Servlet类（StudentServlet.java）：\n\njava\nimport java.io.IOException;\nimport java.util.List;\n\nimport javax.servlet.ServletException;\nimport javax.servlet.http.HttpServlet;\nimport javax.servlet.http.HttpServletRequest;\nimport javax.servlet.http.HttpServletResponse;\n\npublic class StudentServlet extends HttpServlet {\n private static final long serialVersionUID = 1L;\n private StudentDAO studentDAO;\n\n public void init() {\n studentDAO = new StudentDAO();\n }\n\n protected void doPost(HttpServletRequest request, HttpServletResponse response)\n throws ServletException, IOException {\n doGet(request, response);\n }\n\n protected void doGet(HttpServletRequest request, HttpServletResponse response)\n throws ServletException, IOException {\n String action = request.getServletPath();\n\n switch (action) {\n case "/add":\n addStudent(request, response);\n break;\n case "/edit":\n editStudent(request, response);\n break;\n case "/update":\n updateStudent(request, response);\n break;\n case "/delete":\n deleteStudent(request, response);\n break;\n default:\n listStudents(request, response);\n break;\n }\n }\n\n private void addStudent(HttpServletRequest request, HttpServletResponse response)\n throws ServletException, IOException {\n String name = request.getParameter("name");\n String grade = request.getParameter("grade");\n String department = request.getParameter("department");\n\n Student student = new Student(studentDAO.getAllStudents().size() + 1, name, grade, department);\n studentDAO.addStudent(student);\n response.sendRedirect("list");\n }\n\n private void editStudent(HttpServletRequest request, HttpServletResponse response)\n throws ServletException, IOException {\n int id = Integer.parseInt(request.getParameter("id"));\n Student student = studentDAO.getStudentById(id);\n request.setAttribute("student", student);\n request.getRequestDispatcher("edit.jsp").forward(request, response);\n }\n\n private void updateStudent(HttpServletRequest request, HttpServletResponse response)\n throws ServletException, IOException {\n int id = Integer.parseInt(request.getParameter("id"));\n String name = request.getParameter("name");\n String grade = request.getParameter("grade");\n String department = request.getParameter("department");\n\n Student student = new Student(id, name, grade, department);\n studentDAO.updateStudent(student);\n response.sendRedirect("list");\n }\n\n private void deleteStudent(HttpServletRequest request, HttpServletResponse response)\n throws ServletException, IOException {\n int id = Integer.parseInt(request.getParameter("id"));\n studentDAO.deleteStudent(id);\n response.sendRedirect("list");\n }\n\n private void listStudents(HttpServletRequest request, HttpServletResponse response)\n throws ServletException, IOException {\n List<Student> students = studentDAO.getAllStudents();\n request.setAttribute("students", students);\n request.getRequestDispatcher("list.jsp").forward(request, response);\n }\n}\n\n\n以上是一个简单的学生信息管理系统的代码示例，包含了DAO类、Model类和Servlet类。你可以根据自己的需求进行修改和扩展。