后台菜单列表-懒加载列表实现代码

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前言

树状列表数据太多的时候，一次查询出所有数据，组装成树状数据比较浪费性能，所以，采用懒加载的方式，用户每次点击一个节点，查询下该节点下的数据，提高性能。

controller层实现代码

    @GetMapping("/lazy-list")
    @ApiImplicitParams({
            @ApiImplicitParam(name = "code", value = "菜单编号", paramType = "query", dataType = "string"),
            @ApiImplicitParam(name = "name", value = "菜单名称", paramType = "query", dataType = "string")
    })
    @PreAuth(RoleConstant.HAS_ROLE_ADMINISTRATOR)
    @ApiOperation(value = "懒加载列表", notes = "传入menu")
    public R<List<MenuVO>> lazyList(Long parentId, @ApiIgnore @RequestParam Map<String, Object> menu) {
        List<MenuVO> list = menuService.lazyList(parentId, menu);
        return R.data(MenuWrapper.build().listNodeLazyVO(list));
    }

菜单对象的MenuWrapper包装类

/**
 * 包装类,返回视图层所需的字段
 *
 * @author Chill
 */
public class MenuWrapper extends BaseEntityWrapper<Menu, MenuVO> {

	public static MenuWrapper build() {
		return new MenuWrapper();
	}

	@Override
	public MenuVO entityVO(Menu menu) {
		MenuVO menuVO = Objects.requireNonNull(BeanUtil.copy(menu, MenuVO.class));
		if (Func.equals(menu.getParentId(), BladeConstant.TOP_PARENT_ID)) {
			menuVO.setParentName(BladeConstant.TOP_PARENT_NAME);
		} else {
			Menu parent = SysCache.getMenu(menu.getParentId());
			menuVO.setParentName(parent.getName());
		}
		String category = DictCache.getValue(DictEnum.MENU_CATEGORY, Func.toInt(menuVO.getCategory()));
		String action = DictCache.getValue(DictEnum.BUTTON_FUNC, Func.toInt(menuVO.getAction()));
		String open = DictCache.getValue(DictEnum.YES_NO, Func.toInt(menuVO.getIsOpen()));
		menuVO.setCategoryName(category);
		menuVO.setActionName(action);
		menuVO.setIsOpenName(open);
		return menuVO;
	}

	public List<MenuVO> listNodeVO(List<Menu> list) {
		List<MenuVO> collect = list.stream().map(menu -> BeanUtil.copy(menu, MenuVO.class)).collect(Collectors.toList());
		return ForestNodeMerger.merge(collect);
	}

	public List<MenuVO> listNodeLazyVO(List<MenuVO> list) {
		return ForestNodeMerger.merge(list);
	}

}

菜单VO对象代码实现

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
import com.hxtx.spacedata.bladex.domain.entity.system.Menu;
import io.swagger.annotations.ApiModel;
import lombok.Data;
import lombok.EqualsAndHashCode;
import org.springblade.core.tool.node.INode;

import java.util.ArrayList;
import java.util.List;

/**
 * 视图实体类
 *
 * @author Chill
 */
@Data
@EqualsAndHashCode(callSuper = true)
@ApiModel(value = "MenuVO对象", description = "MenuVO对象")
public class MenuVO extends Menu implements INode<MenuVO> {
	private static final long serialVersionUID = 1L;

	/**
	 * 主键ID
	 */
	@JsonSerialize(using = ToStringSerializer.class)
	private Long id;

	/**
	 * 父节点ID
	 */
	@JsonSerialize(using = ToStringSerializer.class)
	private Long parentId;

	/**
	 * 子孙节点
	 */
	@JsonInclude(JsonInclude.Include.NON_EMPTY)
	private List<MenuVO> children;

	/**
	 * 是否有子孙节点
	 */
	@JsonInclude(JsonInclude.Include.NON_EMPTY)
	private Boolean hasChildren;

	@Override
	public List<MenuVO> getChildren() {
		if (this.children == null) {
			this.children = new ArrayList<>();
		}
		return this.children;
	}

	/**
	 * 上级菜单
	 */
	private String parentName;

	/**
	 * 菜单类型
	 */
	private String categoryName;

	/**
	 * 按钮功能
	 */
	private String actionName;

	/**
	 * 是否新窗口打开
	 */
	private String isOpenName;
}

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