写一个 java基于Spring框架的增删改查 教程

好的，下面是一个基于Spring框架的增删改查教程。

1. 配置数据库连接

首先需要在Spring配置文件中配置数据库连接信息，例如以下示例：

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
    <property name="url" value="jdbc:mysql://localhost:3306/mydb"/>
    <property name="username" value="root"/>
    <property name="password" value="123456"/>
</bean>

2. 创建实体类

创建一个Java Bean作为数据库表的映射，例如以下示例：

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

    // 省略getter和setter方法
}

3. DAO层

创建一个DAO（Data Access Object）接口，用于定义数据访问的方法，例如以下示例：

public interface StudentDAO {
    public void addStudent(Student student);
    public void updateStudent(Student student);
    public void deleteStudent(int id);
    public Student getStudentById(int id);
    public List<Student> getAllStudents();
}

4. DAO实现类

创建一个DAO实现类，实现DAO接口中定义的方法，例如以下示例：

@Repository
public class StudentDAOImpl implements StudentDAO {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    public void addStudent(Student student) {
        String sql = "INSERT INTO student(name, age, gender) VALUES (?, ?, ?)";
        jdbcTemplate.update(sql, student.getName(), student.getAge(), student.getGender());
    }

    public void updateStudent(Student student) {
        String sql = "UPDATE student SET name=?, age=?, gender=? WHERE id=?";
        jdbcTemplate.update(sql, student.getName(), student.getAge(), student.getGender(), student.getId());
    }

    public void deleteStudent(int id) {
        String sql = "DELETE FROM student WHERE id=?";
        jdbcTemplate.update(sql, id);
    }

    public Student getStudentById(int id) {
        String sql = "SELECT * FROM student WHERE id=?";
        return jdbcTemplate.queryForObject(sql, new Object[]{id}, new RowMapper<Student>() {
            public Student mapRow(ResultSet rs, int rowNum) throws SQLException {
                Student student = new Student();
                student.setId(rs.getInt("id"));
                student.setName(rs.getString("name"));
                student.setAge(rs.getInt("age"));
                student.setGender(rs.getString("gender"));
                return student;
            }
        });
    }

    public List<Student> getAllStudents() {
        String sql = "SELECT * FROM student";
        return jdbcTemplate.query(sql, new RowMapper<Student>() {
            public Student mapRow(ResultSet rs, int rowNum) throws SQLException {
                Student student = new Student();
                student.setId(rs.getInt("id"));
                student.setName(rs.getString("name"));
                student.setAge(rs.getInt("age"));
                student.setGender(rs.getString("gender"));
                return student;
            }
        });
    }
}

5. Service层

创建一个Service层，用于定义业务逻辑，例如以下示例：

@Service
public class StudentService {

    @Autowired
    private StudentDAO studentDAO;

    public void addStudent(Student student) {
        studentDAO.addStudent(student);
    }

    public void updateStudent(Student student) {
        studentDAO.updateStudent(student);
    }

    public void deleteStudent(int id) {
        studentDAO.deleteStudent(id);
    }

    public Student getStudentById(int id) {
        return studentDAO.getStudentById(id);
    }

    public List<Student> getAllStudents() {
        return studentDAO.getAllStudents();
    }
}

6. 控制器

创建一个控制器，用于处理HTTP请求和响应，例如以下示例：

@Controller
public class StudentController {

    @Autowired
    private StudentService studentService;

    @RequestMapping(value = "/addStudent", method = RequestMethod.POST)
    public String addStudent(@ModelAttribute("student") Student student, Model model) {
        studentService.addStudent(student);
        model.addAttribute("message", "添加成功");
        return "result";
    }

    @RequestMapping(value = "/updateStudent", method = RequestMethod.POST)
    public String updateStudent(@ModelAttribute("student") Student student, Model model) {
        studentService.updateStudent(student);
        model.addAttribute("message", "更新成功");
        return "result";
    }

    @RequestMapping(value = "/deleteStudent/{id}", method = RequestMethod.GET)
    public String deleteStudent(@PathVariable("id") int id, Model model) {
        studentService.deleteStudent(id);
        model.addAttribute("message", "删除成功");
        return "result";
    }

    @RequestMapping(value = "/getStudent/{id}", method = RequestMethod.GET)
    public String getStudent(@PathVariable("id") int id, Model model) {
        Student student = studentService.getStudentById(id);
        model.addAttribute("student", student);
        return "student";
    }

    @RequestMapping(value = "/getAllStudents", method = RequestMethod.GET)
    public String getAllStudents(Model model) {
        List<Student> students = studentService.getAllStudents();
        model.addAttribute("students", students);
        return "students";
    }
}

7. 视图

创建视图，用于展示数据和接收用户输入，例如以下示例：

student.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>学生信息</title>
</head>
<body>
    <h1>学生信息</h1>
    <p>姓名：${student.name}</p>
    <p>年龄：${student.age}</p>
    <p>性别：${student.gender}</p>
</body>
</html>

students.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>学生列表</title>
</head>
<body>
    <h1>学生列表</h1>
    <table>
        <thead>
            <tr>
                <th>ID</th>
                <th>姓名</th>
                <th>年龄</th>
                <th>性别</th>
                <th>操作</th>
            </tr>
        </thead>
        <tbody>
            <c:forEach var="student" items="${students}">
                <tr>
                    <td>${student.id}</td>
                    <td>${student.name}</td>
                    <td>${student.age}</td>
                    <td>${student.gender}</td>
                    <td><a href="/deleteStudent/${student.id}">删除</a></td>
                </tr>
            </c:forEach>
        </tbody>
    </table>
</body>
</html>

result.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>操作结果</title>
</head>
<body>
    <h1>${message}</h1>
    <a href="/getAllStudents">返回列表</a>
</body>
</html>

以上就是一个简单的基于Spring框架的增删改查教程。希望这份教程能够帮助你入门Spring数据库操作。