使用ssm框架实现简单的增删改查的实例

好的，下面我就给你介绍一下如何使用 SSM 框架来实现简单的增删改查。

首先，你需要准备好开发环境，包括 JDK、MySQL 数据库、Maven 和 Eclipse 等软件。接下来，按照以下步骤进行操作：

1. 创建一个 Maven 项目，在 pom.xml 文件中添加 SSM 框架的依赖：

<dependencies>
    <!-- Spring -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>5.2.6.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>5.2.6.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>5.2.6.RELEASE</version>
    </dependency>
    <!-- MyBatis -->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.4</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis-spring</artifactId>
        <version>2.0.4</version>
    </dependency>
    <!-- MySQL Connector -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.22</version>
    </dependency>
</dependencies>

2. 创建数据库表，例如：

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(50) NOT NULL,
  `age` int(11) NOT NULL,
  `email` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4;

3. 创建 JavaBean，例如：

public class User {
    private int id;
    private String name;
    private int age;
    private String email;
    // 省略 getter 和 setter 方法
}

4. 创建 Mapper 接口和 XML 文件，例如：

public interface UserMapper {
    void addUser(User user);
    void deleteUser(int id);
    void updateUser(User user);
    User getUserById(int id);
    List<User> getAllUsers();
}

<?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.UserMapper">
    <insert id="addUser" parameterType="User">
        INSERT INTO `user` (`name`, `age`, `email`) VALUES (#{name}, #{age}, #{email})
    </insert>
    <delete id="deleteUser" parameterType="int">
        DELETE FROM `user` WHERE `id` = #{id}
    </delete>
    <update id="updateUser" parameterType="User">
        UPDATE `user` SET `name` = #{name}, `age` = #{age}, `email` = #{email} WHERE `id` = #{id}
    </update>
    <select id="getUserById" parameterType="int" resultType="User">
        SELECT * FROM `user` WHERE `id` = #{id}
    </select>
    <select id="getAllUsers" resultType="User">
        SELECT * FROM `user`
    </select>
</mapper>

5. 创建 Service 接口和实现类，例如：

public interface UserService {
    void addUser(User user);
    void deleteUser(int id);
    void updateUser(User user);
    User getUserById(int id);
    List<User> getAllUsers();
}

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private UserMapper userMapper;

    @Override
    public void addUser(User user) {
        userMapper.addUser(user);
    }

    @Override
    public void deleteUser(int id) {
        userMapper.deleteUser(id);
    }

    @Override
    public void updateUser(User user) {
        userMapper.updateUser(user);
    }

    @Override
    public User getUserById(int id) {
        return userMapper.getUserById(id);
    }

    @Override
    public List<User> getAllUsers() {
        return userMapper.getAllUsers();
    }
}

6. 创建 Controller 类，例如：

@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;

    @PostMapping("/add")
    public void addUser(@RequestBody User user) {
        userService.addUser(user);
    }

    @DeleteMapping("/delete/{id}")
    public void deleteUser(@PathVariable int id) {
        userService.deleteUser(id);
    }

    @PutMapping("/update")
    public void updateUser(@RequestBody User user) {
        userService.updateUser(user);
    }

    @GetMapping("/get/{id}")
    public User getUserById(@PathVariable int id) {
        return userService.getUserById(id);
    }

    @GetMapping("/getall")
    public List<User> getAllUsers() {
        return userService.getAllUsers();
    }
}

7. 配置 Spring 和 MyBatis，例如：

@Configuration
@MapperScan("com.example.mapper")
public class AppConfig {
    @Bean
    public DataSource dataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai");
        dataSource.setUsername("root");
        dataSource.setPassword("password");
        return dataSource;
    }

    @Bean
    public SqlSessionFactoryBean sqlSessionFactory() throws Exception {
        SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(dataSource());
        return sessionFactory;
    }

    @Bean
    public DataSourceTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dataSource());
    }
}

最后，运行项目，访问 http://localhost:8080/user/getall 可以看到所有的用户信息。你可以根据需要修改代码，实现更多功能。