EasyUI实现异步加载tree(整合Struts2)详解编程语言

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); 
	} 
 
}

效果如图：

项目源码下载：http://download.csdn.net/detail/blog.ytso.com/7852021

转载请注明出处：blog.ytso.com/article/details/38818449