利用Dojo和JSON建立无限级AJAX动态加载的功能模块树

        看了“使用hibernate实现树形结构无限级分类”这篇文章后，我也想将自己在所有开发的项 目中使用的功能模块树的实现方法以及完整DEMO(含源码)贴出来和大家分享。其实在我的博客里是老早贴出来的，由于时间关系没好好整理。

       功能模块树是几乎在每个项目里都要用到的东西，利用Dojo的好处就是可以实现树的子节点的动态加载，这在树节点很多的情况下是很有用的。

        下载附件二dojotree.rar，解压后将dist\dojotree.war部署到应用服务器即可浏览DEMO，DEMO中内置HSQLDB数据库，启动时自动加载。DEMO运行截图见附件一。

一、tree.jsp主要代码

1、首先在head中导入Dojo库(dojo.js)和TreeWidget

<script type=< span="">"text/javascript" src="ajax/dojo/dojo.js">
<script type=<span class="string">"text/javascript">
dojo.require("dojo.widget.Tree");
dojo.require("dojo.widget.TreeNode");
dojo.require("dojo.widget.TreeSelector");
dojo.require("dojo.widget.TreeRPCController");
dojo.require("dojo.widget.TreeLoadingController");
dojo.require("dojo.widget.TreeContextMenu");
</script>

2、在body中放置TreeWidget，TreeLoadingController中的RPCUrl="treeServlet"为从后台获取数据的servlet名称，TreeNode中的expandLevel表示树初始张开级别

<div dojoType="TreeLoadingController" RPCUrl="treeServlet" widgetId="treeController" DNDController="create"><!---->div>
<div dojoType="TreeSelector" widgetId="treeSelector"><!---->div>
<div dojoType="Tree" DNDMode="between" selector="treeSelector" widgetId="bandTree" controller="treeController">
<div dojoType="TreeNode" title="root" widgetId="root" objectId="root" isFolder="true" childIconSrc="images/comm.gif" expandLevel="1"/>

3、建立TreeSelector事件处理函数

function treeSelectFired() {
    // get a reference to the treeSelector and get the selected node
    var treeSelector = dojo.widget.manager.getWidgetById('treeSelector');
    var treeNode = treeSelector.selectedNode;
    // get a reference to the songDisplay div
    var hostDiv = document.getElementById("songDisplay");
    var isFolder = treeNode['isFolder'];
    //alert(isFolder);
    if ( !isFolder) {
       var song = treeNode['title'];
       var url = treeNode['url'];
       link(url);
    } else {
    }
}

4、将select事件处理函数关联到treeSelector

function init() {

    //get a reference to the treeSelector
    var treeSelector = dojo.widget.manager.getWidgetById('treeSelector');

    //connect the select event to the function treeSelectFired()
    dojo.event.connect(treeSelector,'select','treeSelectFired');
}

dojo.addOnLoad(init);

二、主要java代码及数据结构

1、Gnmk.java中tree的属性

 private String id;

 private String gnmkdm;  //功能模块代码

private String gnmksm;  //功能模块说明

private String gnmktb;  //功能模块图标

 private String gnmklj;  //功能模块路径

 private String gnmkmc;  //功能模块名称

private String gnmksj;  //功能模块上级代码

private String gnmkbz;  //功能模块标志（‘N’为叶节点）

2、HSQLDB内存数据库加载SQL(db.sql)

CREATE TABLE GNMK (ID VARCHAR, GNMKDM VARCHAR, GNMKMC VARCHAR, GNMKLJ VARCHAR, GNMKTB VARCHAR, GNMKBZ VARCHAR, GNMKSJ VARCHAR);
INSERT INTO GNMK VALUES ('d098a59f0b765c30010b765d6b780001', '01', '一级目录1', null, 'system.gif', 'Y', '');
INSERT INTO GNMK VALUES ('d098a59f0b765e68010b765fda830001', '0101', '二级目录1', 'cxtjAction.do', 'system.gif', 'N', '01');
INSERT INTO GNMK VALUES ('d098a59f0b765e68010b765fda830001', '0102', '二级目录2', 'cxtjAction.do', 'system.gif', 'N', '01');
INSERT INTO GNMK VALUES ('d098a59f0b765c30010b765d6b780002', '02', '一级目录2', null, 'system.gif', 'Y', '');
INSERT INTO GNMK VALUES ('d098a59f0b765e68010b765fda830002', '0201', '二级目录1', 'cxtjAction.do', 'system.gif', 'N', '02');
INSERT INTO GNMK VALUES ('d098a59f0b765e68010b765fda830002', '0202', '二级目录2', 'cxtjAction.do', 'system.gif', 'Y', '02');
INSERT INTO GNMK VALUES ('d098a59f0b765e68010b765fda830002', '020201', '三级目录1', 'cxtjAction.do', 'system.gif', 'N', '0202');
INSERT INTO GNMK VALUES ('d098a59f0b765e68010b765fda830002', '020202', '三级目录2', 'cxtjAction.do', 'system.gif', 'N', '0202');

3、TreeServlet .java主要代码，在getGnmkByParent(String gnmksj)方法中可以实现自己的业务，DEMO中使用GnmkDAO

public class TreeServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        String action = request.getParameter("action");
        System.out.println("action b=>" + action);
        System.out.println("action b=>" + action);
        String data = request.getParameter("data");
        if (action.equalsIgnoreCase("getChildren")) {
            JSONTokener jsonTokener = new JSONTokener(data);
            JSONObject jsonObject = (JSONObject) jsonTokener.nextValue();
            JSONObject parentNodeObject = (JSONObject) jsonObject.get("node");

            response.setContentType("text/json; charset=gb2312");
            PrintWriter out = response.getWriter();
            out.write(getChildren(parentNodeObject));
        } else {
        }
    }

    private String getChildren(JSONObject parentNodeObject) {
        JSONArray result = new JSONArray();
        String parentObjectId = parentNodeObject.getString("objectId");// id 唯一
        // String parentWidgetId = parentNodeObject.getString("widgetId");// dm
        parentObjectId = parentObjectId.equalsIgnoreCase("root") ? ""
                : parentObjectId;
        System.out.println("parentObjectId=>" + parentObjectId);
        // 获取子功能模块
        List listGnmk = this.getGnmkByParent(parentObjectId);
        System.out.println("listGnmk=>" + listGnmk.size());
        if (listGnmk != null) {
            Iterator itGnmk = listGnmk.iterator();
            while (itGnmk.hasNext()) {
                Gnmk qxgnmk = (Gnmk) itGnmk.next();
                try {
                    JSONObject jsonGnmkObject = new JSONObject();
                    String gnmkbz = qxgnmk.getGnmkbz();
                    boolean isFolder = gnmkbz.equalsIgnoreCase("Y") ? true
                            : false;
                    jsonGnmkObject.put("title", qxgnmk.getGnmkmc());
                    jsonGnmkObject.put("isFolder", isFolder);
                    jsonGnmkObject.put("widgetId", qxgnmk.getGnmkdm());
                    jsonGnmkObject.put("objectId", qxgnmk.getGnmkdm());
                    jsonGnmkObject.put("childIconSrc", "images/"
                            + qxgnmk.getGnmktb());
                    jsonGnmkObject.put("url", qxgnmk.getGnmklj());
                    result.put(jsonGnmkObject);
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }
        return result.toString();
    }

    private List getGnmkByParent(String gnmksj) {
        GnmkDAO gnmkDao = new GnmkDAO();
        return gnmkDao.getGnmkByParent(gnmksj);
    }
}

三、关于DEMO的其它配置说明

1、实现javax.servlet.ServletContextListener接口的contextInitialized方法来加载HSQLDB及其数据， ContextListener.java主要代码

public void contextInitialized(ServletContextEvent event) {
    try {
        // load the driver
        Class.forName("org.hsqldb.jdbcDriver");
        // create the table and add sample data
        InputStreamReader in = new InputStreamReader(getClass().getClassLoader().getResourceAsStream("db.sql"));
        BufferedReader reader = new BufferedReader(in);
        DBUtils.setupDatabase(reader);
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

}

2、web.xml相关配置

<listener>
    <listener-class>
       dojo.sample.ContextListener
    <!----><!---->listener-class>
<!---->>