使用Spring+SpringMVC+Mybatis实现留言板的增删改查

以下是一个简化的例子，展示了如何使用Spring、Spring MVC和MyBatis实现一个留言板的基本功能。

1. 创建数据库表：

CREATE TABLE `message` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `content` varchar(255) NOT NULL,
  `create_time` datetime NOT NULL,
  PRIMARY KEY (`id`)
);

2. 创建Message实体类：

public class Message {
    private Integer id;
    private String content;
    private Date createTime;
    // 省略getter和setter方法
}

3. 创建MessageMapper接口：

@Mapper
public interface MessageMapper {
    int insertMessage(Message message);
    int deleteMessage(Integer id);
    int updateMessage(Message message);
    List<Message> selectAllMessages();
    Message selectMessageById(Integer id);
}

4. 创建MessageMapper.xml文件：

<mapper namespace="MessageMapper">
    <insert id="insertMessage">
        INSERT INTO message(content, create_time) VALUES(#{content}, #{createTime})
    </insert>
    <delete id="deleteMessage">
        DELETE FROM message WHERE id = #{id}
    </delete>
    <update id="updateMessage">
        UPDATE message SET content = #{content}, create_time = #{createTime} WHERE id = #{id}
    </update>
    <select id="selectAllMessages" resultType="Message">
        SELECT * FROM message
    </select>
    <select id="selectMessageById" resultType="Message">
        SELECT * FROM message WHERE id = #{id}
    </select>
</mapper>

5. 配置Spring和MyBatis：

<!-- 配置数据源 -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
    <property name="url" value="jdbc:mysql://localhost:3306/your_database"/>
    <property name="username" value="your_username"/>
    <property name="password" value="your_password"/>
</bean>
 
<!-- 配置SqlSessionFactory -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="dataSource"/>
    <property name="mapperLocations" value="classpath:MessageMapper.xml"/>
</bean>
 
<!-- 配置Mapper接口扫描器 -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com.yourpackage.mapper"/>
</bean>

6. 创建MessageController：

@Controller
@RequestMapping("/messages")
public class MessageController {
    @Autowired
    private MessageMapper messageMapper;
 
    @RequestMapping(method = RequestMethod.GET)
    public String list(Model model) {