基于jsTree的无限级树JSON数据的转换代码

jstree 主页 :
http://www.jstree.com/

其中提供了一种从后台取数据渲染成树的形式：

$("#mytree").tree({ 
data : { 
type : "json", 
url : "${ctx}/user/power!list.do" 
} 
});

对于url中返回的值必须是它定义的json数据形式:

$("#demo2").tree({ 
data : { 
type : "json", 
json : [ 
{ attributes: { id : "pjson_1" }, state: "open", data: "Root node 1", children : [ 
{ attributes: { id : "pjson_2" }, data: { title : "Custom icon", icon : "../media/images/ok.png" } }, 
{ attributes: { id : "pjson_3" }, data: "Child node 2" }, 
{ attributes: { id : "pjson_4" }, data: "Some other child node" } 
]}, 
{ attributes: { id : "pjson_5" }, data: "Root node 2" } 
] 
} 
});

这里需要一个从后台实例集合转换为它规定的json数据的形式.

/** *//** 
* 无限递归获得jsTree的json字串 
* 
* @param parentId 
* 父权限id 
* @return 
*/ 
private String getJson(long parentId) 
{ 
// 把顶层的查出来 
List<Action> actions = actionManager.queryByParentId(parentId); 
for (int i = 0; i < actions.size(); i++) 
{ 
Action a = actions.get(i); 
// 有子节点 
if (a.getIshaschild() == 1) 
{ 
str += "{attributes:{id:\"" + a.getAnid() 
+ "\"},state:\"open\",data:\"" + a.getAnname() + "\" ,"; 
str += "children:["; 
// 查出它的子节点 
List<Action> list = actionManager.queryByParentId(a.getAnid()); 
// 遍历它的子节点 
for (int j = 0; j < list.size(); j++) 
{ 
Action ac = list.get(j); 
//还有子节点(递归调用) 
if (ac.getIshaschild() == 1) 
{ 
this.getJson(ac.getParentid()); 
} 
else 
{ str += "{attributes:{id:\"" + ac.getAnid() 
+ "\"},state:\"open\",data:\"" + ac.getAnname() 
+ "\" " + " }"; 
if (j < list.size() - 1) 
{ 
str += ","; 
} 
} 
} 
str += "]"; 
str += " }"; 
if (i < actions.size() - 1) 
{ 
str += ","; 
} 
} 
} 
return str; 
}

调用:

@org.apache.struts2.convention.annotation.Action(results = 
{ @Result(name = "success", location = "/main/user/action-list.jsp") }) 
public String list() 
{ 
String str = "["; 
// 从根开始 
str += this.getJson(0); 
str += "]"; 
this.renderJson(str); 
return null; 
}

其中Action是菜单类或权限类等的实体。
效果图: