tree

宾仔 2009-03-09

展开全文

Struts2中可以通过s:tree标签轻松的实现一个树状结构。

下面是一个s:tree的具体实现的例子。数的结构用mysql数据库类维护。

1.创建数据库表

DROP TABLE IF EXISTS CATEGORY_MASTER ;
CREATE TABLE CATEGORY_MASTER(
CATEGORY_ID int auto_increment NOT NULL,
CATEGORY_NAME varchar(50) NOT NULL,
PARENT_CATEGORY_ID int DEFAULT -1 NOT NULL,
PRIMARY KEY (CATEGORY_ID)
)

2.创建数据库连接类

参看Struts2中DB操作的一个例子(1)

3.创建Category.java，用来保存DB数据和页面提交的数据

package s2.ex.data;

public class Category {

private int id;

private String name;

private Category[] children;

private int parentNodeId;

public Category[] getChildren() {

return children;

}

public void setChildren(Category[] children) {

this.children = children;

}

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getParentNodeId() {

return parentNodeId;

}

public void setParentNodeId(int parentNodeId) {

this.parentNodeId = parentNodeId;

}

4.创建对数据库表category_master操作的类

package s2.ex.svc;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;

import s2.ex.data.Category;
import s2.ex.db.DBConn;

public class CategoryService {
private static CategoryService instance;
private CategoryService() {

}
public static CategoryService getInstance() {
   if (instance == null){
    instance = new CategoryService();
   }
   return instance;
}
public Category[] getCategoryList() {
   Connection conn = DBConn.getConnection();
   final String SQL = "SELECT * FROM category_master";
   ResultSet rs = null;
   try {
    rs = conn.createStatement().executeQuery(SQL);
    ArrayList<Category> aryResult = new ArrayList<Category>();
    while (rs.next()) {
     Category category = new Category();
     category.setId(rs.getInt("CATEGORY_ID"));
     category.setName(rs.getString("CATEGORY_NAME"));
     aryResult.add(category);
    }
    Category[] result = new Category[aryResult.size()];
    result = aryResult.toArray(result);
    return result;

   } catch (SQLException e) {
    e.printStackTrace();
   } finally {
    try {
     if (rs != null){
      rs.close();
     }
     if (conn != null) {
      if (!conn.isClosed()) {
       conn.close();
      }

     }
    } catch (SQLException e) {
     e.printStackTrace();
    }
   }
   return null;
}
public boolean addNewTreeNode(Category category) {
   Connection conn = DBConn.getConnection();
   final String SQL = "INSERT INTO category_master(CATEGORY_NAME,PARENT_CATEGORY_ID) VALUES(?,?)";
   PreparedStatement pre = null;
   try {
    pre = conn.prepareStatement(SQL);
    pre.setString(1, category.getName());
    pre.setInt(2, category.getParentNodeId());
    int result = pre.executeUpdate();
    if (result >= 0) {
     return true;
    }

   } catch (SQLException e) {
    e.printStackTrace();
   } finally {
    try {

     if (pre != null){
      pre.close();
     }
     if (conn != null) {
      if (!conn.isClosed()) {
       conn.close();
      }

     }
    } catch (SQLException e) {
     e.printStackTrace();
    }
   }
   return false;
}
public Category[] getAllCategory() {
   Connection conn = DBConn.getConnection();
   final String SQL = "SELECT * FROM category_master where PARENT_CATEGORY_ID=-1";
   ResultSet rs = null;
   try {
    rs = conn.createStatement().executeQuery(SQL);
    ArrayList<Category> aryResult = new ArrayList<Category>();
    while (rs.next()) {
     Category category = new Category();
     category.setId(rs.getInt("CATEGORY_ID"));
     category.setName(rs.getString("CATEGORY_NAME"));
     category.setChildren(this.getChildren(category.getId()));
     aryResult.add(category);
    }
    Category[] result = new Category[aryResult.size()];
    result = aryResult.toArray(result);
    return result;

     }
    } catch (SQLException e) {
     e.printStackTrace();
    }
   }
   return null;
}
public Category[] getChildren(int categoryId) {
   Connection conn = DBConn.getConnection();
   final String SQL = "SELECT * FROM category_master where PARENT_CATEGORY_ID=?";
   PreparedStatement pre = null;
   ResultSet rs = null;
   try {
    pre = conn.prepareStatement(SQL);
    pre.setInt(1, categoryId);
    rs = pre.executeQuery();
    ArrayList<Category> aryResult = new ArrayList<Category>();
    while (rs.next()) {
     Category category = new Category();
     category.setId(rs.getInt("CATEGORY_ID"));
     category.setName(rs.getString("CATEGORY_NAME"));
     category.setChildren(this.getChildren(category.getId()));
     aryResult.add(category);
    }
    Category[] result = new Category[aryResult.size()];
    result = aryResult.toArray(result);
    return result;
   } catch (SQLException e) {
    e.printStackTrace();
   } finally {
    try {
     if (rs != null){
      rs.close();
     }
     if (pre != null){
      pre.close();
     }
     if (conn != null) {
      if (!conn.isClosed()) {
       conn.close();
      }

     }
    } catch (SQLException e) {
     e.printStackTrace();
    }
   }
   return null;
}
}

上面getChildren方法里面用到了递归。

5.创建action类

package s2.ex.action;

import s2.ex.data.Category;
import s2.ex.svc.CategoryService;

import com.opensymphony.xwork2.ActionSupport;

public class SimpleTreeAction extends ActionSupport {

private static final long serialVersionUID = 1L;
private Category root;
private Category[] parentNodeIds;
private Category editCategory;
public String displayTree() {
   root = new Category();
   root.setId(-1);
   root.setName("root");
   root.setChildren(CategoryService.getInstance().getAllCategory());
   return SUCCESS;
}
public Category getRoot() {
   return root;
}
public void setRoot(Category root) {
   this.root = root;
}
public String goTreeEdit(){
   this.parentNodeIds = CategoryService.getInstance().getCategoryList();
   return SUCCESS;
}
public Category[] getParentNodeIds() {
   return parentNodeIds;
}
public void setParentNodeIds(Category[] parentNodeIds) {
   this.parentNodeIds = parentNodeIds;
}

public Category getEditCategory() {
   return editCategory;
}
public void setEditCategory(Category editCategory) {
   this.editCategory = editCategory;
}
public String saveTreeNode() {
   if (CategoryService.getInstance().addNewTreeNode(this.editCategory)){
    return SUCCESS;
   }else {
    return INPUT;
   }
}
}

6.创建TreeIndex.jsp，用来显示树

<%@ page contentType="text/html; charset=UTF-8" %>
<%@page pageEncoding="utf-8" %>
<%@taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>Tree</title>
<s:head theme="ajax" debug="true" />
</head>

<body>
<script language="JavaScript">
function treeNodeSelected(arg) {
    alert("id["+arg.source.widgetId+"], name["+ arg.source.title+ "] selected");
}
dojo.addOnLoad(function() {
    var s = dojo.widget.byId('treeTestId').selector;
    dojo.event.connect(s, 'select', 'treeNodeSelected');
});</script>
<div style="float:left; margin-right: 50px;">
<s:tree id="treeTestId"
theme="ajax"
rootNode="root"
childCollectionProperty="children"
nodeIdProperty="id"
nodeTitleProperty="name"
treeSelectedTopic="treeSelected">
</s:tree>
<s:form action="GoTreeEdit">
<s:submit value="Add New"/>
</s:form>
</div>

</body>
</html>

7.创建用来增加节点的TreeEdit.jsp

<%@ page contentType="text/html; charset=UTF-8" %>
<%@page pageEncoding="utf-8" %>
<%@taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>Session Test</title>
<s:head theme="xhtml"/>
</head>

</body>
</html>

8.配置struts.xml

<package name="Test" extends="struts-default" namespace="/test">
   <action name="DisplayTree" class="s2.ex.action.SimpleTreeAction" method="displayTree">
    <result>TreeIndex.jsp</result>
   </action>
   <action name="GoTreeEdit" class="s2.ex.action.SimpleTreeAction" method="goTreeEdit">
    <result>TreeEdit.jsp</result>
   </action>
   <action name="SaveTreeNode" class="s2.ex.action.SimpleTreeAction" method="saveTreeNode">
    <result name="input">TreeEdit.jsp</result>
    <result type="redirect">DisplayTree.action</result>
   </action>
</package>