controller层用Map，如何在mapper里面引用

在Spring MVC架构中，Controller层通常会使用Map存储数据，例如保存请求参数到Map中以便后续处理。而在Mapper层（通常用于数据库操作），如果需要从Controller层获取这些数据，你可以通过以下步骤进行：

1. **注入Map**：在Mapper接口或者实现类上，使用@Autowired或@Resource注解将Controller层的Map注入进来。例如：

public interface MyMapper {
    void operate(@Autowired Map<String, Object> params);
}

2. **访问Map**：在具体的Mapper方法中，可以直接使用`params`关键字来访问Map中的值，假设键名为你要的操作参数：

void executeOperation(String paramKey) {
    String paramValue = (String) params.get(paramKey); // 获取Map中的字符串值
    // 使用paramValue进行数据库查询或操作
}

记得在Controller层处理完Map后将其设置好，然后注入给Mapper。

相关问题

Controller service mapper

As an AI language model, I do not have knowledge of specific tools or software. However, a controller service mapper is typically a software tool or framework that is used to map and manage controller services in a distributed computing environment. Controller services are software components that are responsible for managing and providing access to resources or data in a distributed system. A controller service mapper helps to simplify the management of these services by providing a centralized view of the services and their dependencies. It can also help to optimize the performance of the system by identifying and resolving any bottlenecks or issues with the services. The specific features and capabilities of a controller service mapper may vary depending on the specific tool or framework being used.

使用Java编程和springboot框架实现菜单权限表的树状结构接口，给出相应的controller层，service层，daoc层及mapper，

好的，下面是完整的代码实现。

先定义一个菜单权限的实体类`MenuPermission`，包含菜单ID、菜单名称、父级菜单ID等属性：

public class MenuPermission {
    private Long menuId;
    private String menuName;
    private Long parentId;

    // 省略getter和setter方法
}

定义一个菜单权限的Mapper接口`MenuPermissionMapper`，使用MyBatis注解实现SQL语句的映射。其中，`selectAll()`方法用于查询全部菜单权限数据：

@Mapper
public interface MenuPermissionMapper {
    @Select("SELECT * FROM menu_permission")
    List<MenuPermission> selectAll();
}

定义一个菜单权限的服务类`MenuPermissionService`，用于获取全部菜单权限数据：

@Service
public class MenuPermissionService {
    // 假设菜单权限数据存储在MySQL数据库中
    @Autowired
    private MenuPermissionMapper menuPermissionMapper;

    /**
     * 获取全部菜单权限数据
     */
    public List<MenuPermission> getAllMenuPermissions() {
        return menuPermissionMapper.selectAll();
    }
}

定义一个菜单权限的控制器`MenuPermissionController`，用于提供树状结构的菜单权限数据接口`/menu/tree`。其中，`buildMenuPermissionTree()`方法用于构建树状结构，`getMenuPermissionTree()`方法用于返回树状结构的菜单权限数据：

@RestController
@RequestMapping("/menu")
public class MenuPermissionController {
    @Autowired
    private MenuPermissionService menuPermissionService;

    @GetMapping("/tree")
    public List<MenuPermission> getMenuPermissionTree() {
        // 获取全部菜单权限数据
        List<MenuPermission> allMenuPermissions = menuPermissionService.getAllMenuPermissions();
        // 构建树状结构
        return buildMenuPermissionTree(allMenuPermissions);
    }

    /**
     * 构建树状结构的菜单权限数据
     */
    private List<MenuPermission> buildMenuPermissionTree(List<MenuPermission> menuPermissions) {
        // 构建菜单ID到菜单权限的映射表
        Map<Long, MenuPermission> menuIdMap = new HashMap<>();
        for (MenuPermission menuPermission : menuPermissions) {
            menuIdMap.put(menuPermission.getMenuId(), menuPermission);
        }

        // 构建父级菜单ID到子菜单列表的映射表
        Map<Long, List<MenuPermission>> parentIdMap = new HashMap<>();
        for (MenuPermission menuPermission : menuPermissions) {
            Long parentId = menuPermission.getParentId();
            if (parentId != null) {
                List<MenuPermission> childMenuPermissions = parentIdMap.computeIfAbsent(parentId, k -> new ArrayList<>());
                childMenuPermissions.add(menuPermission);
            }
        }

        // 遍历菜单权限数据，构建树状结构
        List<MenuPermission> rootMenuPermissions = new ArrayList<>();
        for (MenuPermission menuPermission : menuPermissions) {
            Long parentId = menuPermission.getParentId();
            if (parentId == null) {
                // 当前菜单是根菜单，直接添加到根菜单列表中
                rootMenuPermissions.add(menuPermission);
            } else {
                // 当前菜单是子菜单，添加到父级菜单的子菜单列表中
                MenuPermission parentMenuPermission = menuIdMap.get(parentId);
                if (parentMenuPermission != null) {
                    List<MenuPermission> childMenuPermissions = parentIdMap.get(parentId);
                    if (childMenuPermissions == null) {
                        childMenuPermissions = new ArrayList<>();
                        parentIdMap.put(parentId, childMenuPermissions);
                    }
                    childMenuPermissions.add(menuPermission);
                }
            }
        }
        return rootMenuPermissions;
    }
}

最后，我们需要在`application.properties`文件中配置数据库连接信息：

spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

以上就是完整的代码实现。需要注意的是，我们需要在`pom.xml`文件中添加相关依赖，如下所示：

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>

    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.1.4</version>
    </dependency>
</dependencies>