Freemarker如何生成树形导航菜单（递归）

很多导航菜单是树形的，即一级一级往下分，这样的结构固然需要用递归来处理。

对于Freemarker 来说，宏就相当于函数，其定义了签名及参数列表。

所以在freemarker页面应这样写：

<#macro menuTree menus>
  <#if menus?? && menus?size gt 0>
   <#list menus as menu>
    <tr>
     <td>
      <input type="checkbox" name="ids" value="${menu.id}" />
     </td>
     <td>
   <span title="${menu.name!}" style="margin-left: ${menu.leaf * 30}px;[#if menu.leaf == 0] color: #000000;[/#if]">
   ${menu.menuName!}
   </span>
     </td>
     <td>
     ${menu.url!}
     </td>
     <td>
     ${menu.permissionText!}
     </td>
     <td>
     ${menu.sortNo!}
     </td>
     <td>
      <a href="edit.jhtml?id=${menu.id}">[编辑]</a>
     </td>
    </tr>
   <#if menu.menuBeans?? && menu.menuBeans?size gt 0>
    <@menuTree menus = menu.menuBeans/>
   </#if>
   </#list>
  </#if>
 </#macro>
 <!-- 调用宏 生成递归树 -->
<@menuTree menus = dto />

后台数据：

[
 {
  "id": 1,
  "enable": true,
  "remark": null,
  "createBy": 1,
  "createTime": 1503546411000,
  "updateBy": 1,
  "updateTime": 1503546415000,
  "keyword": null,
  "menuName": "系统管理",
  "menuType": 1,
  "parentId": null,
  "iconcls": null,
  "url": null,
  "expand": null,
  "sortNo": null,
  "permission": null,
  "moduleId": 1,
  "parentName": null,
  "leaf": 0,
  "typeName": null,
  "permissionText": null,
  "menuBeans": [
   {
    "id": 7,
    "enable": true,
    "remark": null,
    "createBy": 1,
    "createTime": 1503546411000,
    "updateBy": 1,
    "updateTime": 1503546415000,
    "keyword": null,
    "menuName": "模块管理",
    "menuType": 1,
    "parentId": 1,
    "iconcls": null,
    "url": "/module/list",
    "expand": null,
    "sortNo": null,
    "permission": null,
    "moduleId": 1,
    "parentName": null,
    "leaf": 1,
    "typeName": null,
    "permissionText": null,
    "menuBeans": null
   },
   {
    "id": 3,
    "enable": true,
    "remark": null,
    "createBy": 1,
    "createTime": 1503546411000,
    "updateBy": 1,
    "updateTime": 1503546415000,
    "keyword": null,
    "menuName": "菜单管理",
    "menuType": 1,
    "parentId": 1,
    "iconcls": null,
    "url": "/menu/list",
    "expand": null,
    "sortNo": null,
    "permission": "admin:add",
    "moduleId": 1,
    "parentName": null,
    "leaf": 1,
    "typeName": null,
    "permissionText": null,
    "menuBeans": null
   }
  ]
 },
 {
  "id": 2,
  "enable": true,
  "remark": null,
  "createBy": 1,
  "createTime": 1503546411000,
  "updateBy": 1,
  "updateTime": 1503546415000,
  "keyword": null,
  "menuName": "用户管理",
  "menuType": 1,
  "parentId": null,
  "iconcls": null,
  "url": null,
  "expand": null,
  "sortNo": null,
  "permission": null,
  "moduleId": 1,
  "parentName": null,
  "leaf": 0,
  "typeName": null,
  "permissionText": null,
  "menuBeans": [
   {
    "id": 9,
    "enable": true,
    "remark": null,
    "createBy": 1,
    "createTime": 1503546411000,
    "updateBy": 1,
    "updateTime": 1503546415000,
    "keyword": null,
    "menuName": "供应商管理",
    "menuType": 1,
    "parentId": 2,
    "iconcls": null,
    "url": null,
    "expand": null,
    "sortNo": null,
    "permission": null,
    "moduleId": 1,
    "parentName": null,
    "leaf": 1,
    "typeName": null,
    "permissionText": null,
    "menuBeans": null
   },
   {
    "id": 8,
    "enable": true,
    "remark": null,
    "createBy": 1,
    "createTime": 1503546411000,
    "updateBy": 1,
    "updateTime": 1503546415000,
    "keyword": null,
    "menuName": "部门管理",
    "menuType": 1,
    "parentId": 2,
    "iconcls": null,
    "url": null,
    "expand": null,
    "sortNo": null,
    "permission": null,
    "moduleId": 1,
    "parentName": null,
    "leaf": 1,
    "typeName": null,
    "permissionText": null,
    "menuBeans": null
   },
   {
    "id": 6,
    "enable": true,
    "remark": null,
    "createBy": 1,
    "createTime": 1503546411000,
    "updateBy": 1,
    "updateTime": 1503546415000,
    "keyword": null,
    "menuName": "权限管理",
    "menuType": 1,
    "parentId": 2,
    "iconcls": null,
    "url": "/user/list-6",
    "expand": null,
    "sortNo": null,
    "permission": null,
    "moduleId": 1,
    "parentName": null,
    "leaf": 1,
    "typeName": null,
    "permissionText": null,
    "menuBeans": null
   },
   {
    "id": 5,
    "enable": true,
    "remark": null,
    "createBy": 1,
    "createTime": 1503546411000,
    "updateBy": 1,
    "updateTime": 1503546415000,
    "keyword": null,
    "menuName": "角色管理",
    "menuType": 1,
    "parentId": 2,
    "iconcls": null,
    "url": "/user/list-5",
    "expand": null,
    "sortNo": null,
    "permission": null,
    "moduleId": 1,
    "parentName": null,
    "leaf": 1,
    "typeName": null,
    "permissionText": null,
    "menuBeans": null
   },
   {
    "id": 4,
    "enable": true,
    "remark": null,
    "createBy": 1,
    "createTime": 1503546411000,
    "updateBy": 1,
    "updateTime": 1503546415000,
    "keyword": null,
    "menuName": "分销商管理",
    "menuType": 1,
    "parentId": 2,
    "iconcls": null,
    "url": "/user/add-4",
    "expand": null,
    "sortNo": null,
    "permission": null,
    "moduleId": 1,
    "parentName": null,
    "leaf": 1,
    "typeName": null,
    "permissionText": null,
    "menuBeans": null
   },
   {
    "id": 10,
    "enable": true,
    "remark": null,
    "createBy": 1,
    "createTime": 1503546411000,
    "updateBy": 1,
    "updateTime": 1503546415000,
    "keyword": null,
    "menuName": "员工管理",
    "menuType": 1,
    "parentId": 2,
    "iconcls": null,
    "url": null,
    "expand": null,
    "sortNo": null,
    "permission": null,
    "moduleId": 1,
    "parentName": null,
    "leaf": 1,
    "typeName": null,
    "permissionText": null,
    "menuBeans": null
   }
  ]
 }
]

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