SSM框架web开发代码

SSM（Spring + SpringMVC + MyBatis）是一种常用的 Java Web 开发框架组合，下面是一个简单的 SSM 框架的示例代码，用于实现一个简单的增删改查的学生信息管理系统：

首先是 `Student` 实体类：

public class Student {
    private Integer id;
    private String name;
    private Integer age;
    private String gender;
    private String major;
    // 省略 getter 和 setter 方法
}

接下来是 `StudentMapper` 接口，用于定义增删改查的方法：

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

然后是 `StudentMapper.xml` 文件，用于实现这些方法：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.example.mapper.StudentMapper">
    <resultMap id="StudentResultMap" type="com.example.entity.Student">
        <id column="id" property="id" />
        <result column="name" property="name" />
        <result column="age" property="age" />
        <result column="gender" property="gender" />
        <result column="major" property="major" />
    </resultMap>

    <select id="getAllStudents" resultMap="StudentResultMap">
        SELECT * FROM student;
    </select>

    <select id="getStudentById" resultMap="StudentResultMap">
        SELECT * FROM student WHERE id=#{id};
    </select>

    <insert id="addStudent">
        INSERT INTO student (name, age, gender, major) VALUES (#{name}, #{age}, #{gender}, #{major});
    </insert>

    <update id="updateStudent">
        UPDATE student SET name=#{name}, age=#{age}, gender=#{gender}, major=#{major} WHERE id=#{id};
    </update>

    <delete id="deleteStudent">
        DELETE FROM student WHERE id=#{id};
    </delete>
</mapper>

然后是 `StudentService` 接口，用于定义具体的增删改查操作：

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

接下来是 `StudentServiceImpl` 类，用于实现这些操作：

@Service
public class StudentServiceImpl implements StudentService {

    @Autowired
    private StudentMapper studentMapper;

    @Override
    public List<Student> getAllStudents() {
        return studentMapper.getAllStudents();
    }

    @Override
    public Student getStudentById(Integer id) {
        return studentMapper.getStudentById(id);
    }

    @Override
    public void addStudent(Student student) {
        studentMapper.addStudent(student);
    }

    @Override
    public void updateStudent(Student student) {
        studentMapper.updateStudent(student);
    }

    @Override
    public void deleteStudent(Integer id) {
        studentMapper.deleteStudent(id);
    }
}

最后是 `StudentController` 类，用于处理 HTTP 请求和响应：

@Controller
@RequestMapping("/student")
public class StudentController {

    @Autowired
    private StudentService studentService;

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

    @RequestMapping("/add")
    public String add() {
        return "add";
    }

    @RequestMapping("/doAdd")
    public String doAdd(Student student) {
        studentService.addStudent(student);
        return "redirect:/student/list";
    }

    @RequestMapping("/edit")
    public String edit(Integer id, Model model) {
        Student student = studentService.getStudentById(id);
        model.addAttribute("student", student);
        return "edit";
    }

    @RequestMapping("/doEdit")
    public String doEdit(Student student) {
        studentService.updateStudent(student);
        return "redirect:/student/list";
    }

    @RequestMapping("/delete")
    public String delete(Integer id) {
        studentService.deleteStudent(id);
        return "redirect:/student/list";
    }
}

在上面的代码中，`@Controller` 注解表示这是一个控制器类，`@RequestMapping` 注解用于映射 HTTP 请求路径。`Model` 参数用于向视图传递数据。`redirect:/student/list` 表示重定向到 `/student/list` 路径。

最后，在 `src/main/resources` 目录下创建 `applicationContext.xml` 文件，配置 Spring、MyBatis 和数据库连接信息：

<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">

    <context:component-scan base-package="com.example" />

    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.example.mapper" />
    </bean>

    <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/test" />
        <property name="username" value="root" />
        <property name="password" value="" />
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="typeAliasesPackage" value="com.example.entity" />
        <property name="mapperLocations" value="classpath:com/example/mapper/*.xml" />
    </bean>

    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>

    <tx:annotation-driven />
</beans>

这里使用的是 MySQL 数据库，修改 `url`、`username` 和 `password` 属性以适应你的环境。

以上就是一个简单的 SSM 框架的示例代码，它实现了一个简单的增删改查的学生信息管理系统。