Freemarker 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
}
]
}
]