EasyUI实现异步加载tree 整合Struts2

最新推荐文章于 2019-05-05 23:38:01 发布

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最新推荐文章于 2019-05-05 23:38:01 发布

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本文链接：https://blog.youkuaiyun.com/hffygc/article/details/86687944

本文详细介绍了如何在EasyUI框架中使用Tree组件，并通过Struts2框架实现数据的动态加载。从配置Action到JDBC数据查询，再到JSON数据格式的处理，提供了完整的代码示例。

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首先jsp页面有一ul用于展现Tree

<ul id="mytree"></ul>

加载Tree

<script type="text/javascript"> $('#mytree').tree({        url:'treeLoad.action' }); </script>

配置Action

<struts> <package name="tree_json" extends="json-default">  <action name="treeLoad" method="treeLoad" class="com.home.web.TreeAction">   <result type="json">    <param name="root">treeNodes</param>   </result>  </action> </package></struts>

注意：

1.extends是json-default,表示返回json对象格式。

2.result中param的name为root,里面设置的值就是action中要返回的JSON对象

需要封装对象Tree

public class TreeNode { private static final long serialVersionUID = 1L; private String id;   // 节点id private String text; // 显示的节点文本 private String state = "open"; // 节点状态,'open'或者'closed',默认是'open' private boolean checked;       // 指明检查节点是否选中. public TreeNode() {} public TreeNode(String id, String text, String state, boolean checked) {  this.id = id;  this.text = text;  this.state = state;  this.checked = checked; } //...省略setXX() getXX()}

表结构如图

首先查询所有parentid为空值的数据,然后同时判断该节点下是否有子节点，如果有则状态是关闭状态

当继续展开树的时候会将该ID值传入,然后查询该节点的子节点。

action方法实现

import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.ArrayList;import java.util.List;import com.home.util.ConnectionManager;/** * 查询数据使用JDBC进行操作  * */public class TreeAction { private List<TreeNode> treeNodes = new ArrayList<TreeNode>(); //返回的JSON数据 private String id; // 树组件使用的ID public String treeLoad() {  Statement sta = null;  ResultSet rs = null;  try {   Connection conn = ConnectionManager.getConnection();   sta = conn.createStatement();   String sql = "";   if (id == null) {  //如果id为null则是根节点     sql = "select * from easyui_tree where parentid = ''";   } else {           //查询下面的子节点     sql = "select * from easyui_tree where parentid = " + id;   }   rs = sta.executeQuery(sql);   while (rs.next()) {    String id = rs.getString("id");    String name = rs.getString("name");    TreeNode node = new TreeNode();    node.setId(id);    node.setText(name);    node.setChecked(false);    //判断是否有子节点，如果有则closed否则open    if(isChildrenNode(id)){     node.setState("closed");    }else{     node.setState("open");    }        treeNodes.add(node);   }   // 关闭所有资源   ConnectionManager.closeAll(rs, sta, conn);  } catch (SQLException e) {   e.printStackTrace();  }  return "success"; } /**  * 判断是否有子节点  *   * @return  */ public boolean isChildrenNode(String id) {  Boolean flag = false;  Statement sta = null;  ResultSet rs = null;  try {   Connection conn = ConnectionManager.getConnection();   sta = conn.createStatement();   String sql = "select * from easyui_tree where parentid = " + id;   rs = sta.executeQuery(sql);   while (rs.next()) {    flag = true;   }   // 关闭所有资源   ConnectionManager.closeAll(rs, sta, conn);  } catch (SQLException e) {   e.printStackTrace();  }  return flag; } public List<TreeNode> getTreeNodes() {  return treeNodes; } public void setTreeNodes(List<TreeNode> treeNodes) {  this.treeNodes = treeNodes; } public String getId() {  return id; } public void setId(String id) {  this.id = id; }}

对获取Connection的方法进行了封装

import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class ConnectionManager { public static final String DRIVER = "com.mysql.jdbc.Driver"; public static final String URL = "jdbc:mysql://localhost:3306/easyui"; public static final String USERNAME = "root"; public static final String PASSWORD = "root"; /**  * 通过静态代码块 注册数据库驱动  */ static {  try {   Class.forName(DRIVER);  } catch (ClassNotFoundException e) {   e.printStackTrace();  } } /**  * 获得Connection  *   * @return  */ public static Connection getConnection() {  Connection conn = null;  try {   conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);  } catch (SQLException e) {   e.printStackTrace();  }  return conn; } /**  * 关闭ResultSet  *   * @param rs  */ public static void closeResultSet(ResultSet rs) {  if (rs != null) {   try {    rs.close();   } catch (SQLException e) {    e.printStackTrace();   }  } } /**  * 关闭Statement  *   * @param st  */ public static void closeStatement(Statement st) {  if (st != null) {   try {    st.close();   } catch (SQLException e) {    e.printStackTrace();   }  } } /**  * 关闭Connection  *   * @param conn  */ public static void closeConnection(Connection conn) {  if (conn != null) {   try {    conn.close();   } catch (SQLException e) {    e.printStackTrace();   }  } } /**  * 关闭全部  *   * @param rs  * @param sta  * @param conn  */ public static void closeAll(ResultSet rs, Statement sta, Connection conn) {  closeResultSet(rs);  closeStatement(sta);  closeConnection(conn); }}