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发表时间:2008-08-29
struts 2中的doubleselect 实现了级联操作,本文通过一个简单的是实例,说明怎样对数据库中的表进行级联。 希望对初学者有点滴的帮助。 本文给出了完整的实现过程,并有源代码下载。 本文参考了http://opas.iteye.com/blog/183518 向作者表示谢意
注意:用IE来看本文,要不然贴图看不到
首先建立数据库 CREATE DATABASE JPETSTORE; USE JPETSTORE; create table category ( catid varchar(10) not null, name varchar(80) null, descn varchar(255) null, constraint pk_category primary key (catid) ); create table product ( productid varchar(10) not null, category varchar(10) not null, name varchar(80) null, descn varchar(255) null, constraint pk_product primary key (productid), constraint fk_product_1 foreign key (category) references category (catid) ); INSERT INTO category VALUES ('FISH','Fish','<image src="../images/fish_icon.gif"><font size="5" color="blue"> Fish</font>'); INSERT INTO category VALUES ('DOGS','Dogs','<image src="../images/dogs_icon.gif"><font size="5" color="blue"> Dogs</font>'); INSERT INTO category VALUES ('REPTILES','Reptiles','<image src="../images/reptiles_icon.gif"><font size="5" color="blue"> Reptiles</font>'); INSERT INTO category VALUES ('CATS','Cats','<image src="../images/cats_icon.gif"><font size="5" color="blue"> Cats</font>'); INSERT INTO category VALUES ('BIRDS','Birds','<image src="../images/birds_icon.gif"><font size="5" color="blue"> Birds</font>'); INSERT INTO product VALUES ('FI-SW-01','FISH','Angelfish','<image src="../images/fish1.gif">Salt Water fish from Australia'); INSERT INTO product VALUES ('FI-SW-02','FISH','Tiger Shark','<image src="../images/fish4.gif">Salt Water fish from Australia'); INSERT INTO product VALUES ('FI-FW-01','FISH', 'Koi','<image src="../images/fish3.gif">Fresh Water fish from Japan'); INSERT INTO product VALUES ('FI-FW-02','FISH', 'Goldfish','<image src="../images/fish2.gif">Fresh Water fish from China'); INSERT INTO product VALUES ('K9-BD-01','DOGS','Bulldog','<image src="../images/dog2.gif">Friendly dog from England'); INSERT INTO product VALUES ('K9-PO-02','DOGS','Poodle','<image src="../images/dog6.gif">Cute dog from France'); INSERT INTO product VALUES ('K9-DL-01','DOGS', 'Dalmation','<image src="../images/dog5.gif">Great dog for a Fire Station'); INSERT INTO product VALUES ('K9-RT-01','DOGS', 'Golden Retriever','<image src="../images/dog1.gif">Great family dog'); INSERT INTO product VALUES ('K9-RT-02','DOGS', 'Labrador Retriever','<image src="../images/dog5.gif">Great hunting dog'); INSERT INTO product VALUES ('K9-CW-01','DOGS', 'Chihuahua','<image src="../images/dog4.gif">Great companion dog'); INSERT INTO product VALUES ('RP-SN-01','REPTILES','Rattlesnake','<image src="../images/snake1.gif">Doubles as a watch dog'); INSERT INTO product VALUES ('RP-LI-02','REPTILES','Iguana','<image src="../images/lizard1.gif">Friendly green friend'); INSERT INTO product VALUES ('FL-DSH-01','CATS','Manx','<image src="../images/cat2.gif">Great for reducing mouse populations'); INSERT INTO product VALUES ('FL-DLH-02','CATS','Persian','<image src="../images/cat1.gif">Friendly house cat, doubles as a princess'); INSERT INTO product VALUES ('AV-CB-01','BIRDS','Amazon Parrot','<image src="../images/bird2.gif">Great companion for up to 75 years'); INSERT INTO product VALUES ('AV-SB-02','BIRDS','Finch','<image src="../images/bird1.gif">Great stress reliever'); 项目贴图:
数据库操作代码 package petstore.dbc; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; public class DataBaseConnection { private String DBDRIVER = "com.mysql.jdbc.Driver"; private String DBURL = "jdbc:mysql://localhost:3306/jpetstore?characterEncoding=gbk"; private String DBUSER = "root"; private String DBPASSWORD = ""; private Connection conn = null; public DataBaseConnection() { try { Class.forName(DBDRIVER); this.conn = DriverManager.getConnection(DBURL, DBUSER, DBPASSWORD); } catch (ClassNotFoundException e) { System.out.println("驱动程序不存在或名字写错"); System.out.println(e.getMessage()); } catch (SQLException e) { System.out.println("数据库操作错误"); System.out.println(e.getMessage()); } } public Connection getConnection() { return this.conn; } public void close() { try { this.conn.close(); } catch (Exception e) { } } }; 用到的实体类 package petstore.model; import java.io.Serializable; public class Category implements Serializable { private String categoryId; private String name; private String description; public String getCategoryId() { return categoryId; } public void setCategoryId(String categoryId) { this.categoryId = categoryId.trim(); } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } } package petstore.model; import java.io.Serializable; public class Product implements Serializable { private String productId; private String categoryId; private String name; private String description; public String getProductId() { return productId; } public void setProductId(String productId) { this.productId = productId.trim(); } public String getCategoryId() { return categoryId; } public void setCategoryId(String categoryId) { this.categoryId = categoryId; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } public String toString() { return getName(); } } dao类: /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package petstore.dao; import petstore.dbc.DataBaseConnection; import petstore.model.Category; import java.sql.* ; import java.util.* ; public class CategoryDao { // 增加操作 // 查询全部 public List<Category> findAll() throws Exception { List <Category>all = new ArrayList<Category>() ; String sql = "SELECT CatId,name,descn FROM Category" ; PreparedStatement pstmt = null ; DataBaseConnection dbc = null ; dbc = new DataBaseConnection() ; try { pstmt = dbc.getConnection().prepareStatement(sql) ; ResultSet rs = pstmt.executeQuery() ; while(rs.next()) { Category Category = new Category() ; Category.setCategoryId(rs.getString(1)) ; Category.setName(rs.getString(2)) ; Category.setDescription(rs.getString(3)) ; all.add(Category) ; } rs.close() ; pstmt.close() ; } catch (Exception e) { System.out.println(e) ; throw new Exception("操作中出现错误!!!") ; } finally { dbc.close() ; } return all ; } // 模糊查询 }; /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package petstore.dao; import petstore.dbc.DataBaseConnection; import petstore.model.Product; import java.sql.* ; import java.util.* ; public class ProductDao { // 增加操作 // 查询全部 public List findAll() throws Exception { List all = new ArrayList() ; String sql = "SELECT productId,categoryId,name,description FROM Product" ; PreparedStatement pstmt = null ; DataBaseConnection dbc = null ; dbc = new DataBaseConnection() ; try { pstmt = dbc.getConnection().prepareStatement(sql) ; ResultSet rs = pstmt.executeQuery() ; while(rs.next()) { Product Product = new Product() ; Product.setProductId(rs.getString(1)) ; Product.setCategoryId(rs.getString(2)) ; Product.setName(rs.getString(3)) ; Product.setDescription(rs.getString(4)) ; all.add(Product) ; } rs.close() ; pstmt.close() ; } catch (Exception e) { System.out.println(e) ; throw new Exception("操作中出现错误!!!") ; } finally { dbc.close() ; } return all ; } public List findProductByCategoryId(String id) throws Exception { List all = new ArrayList() ; String sql = "SELECT productId,category,name,descn FROM Product where category=? " ; PreparedStatement pstmt = null ; DataBaseConnection dbc = null ; dbc = new DataBaseConnection() ; try { pstmt = dbc.getConnection().prepareStatement(sql) ; pstmt.setString(1, id); ResultSet rs = pstmt.executeQuery() ; while(rs.next()) { Product product = new Product() ; product.setProductId(rs.getString(1)) ; product.setCategoryId(rs.getString(2)) ; product.setName(rs.getString(3)) ; product.setDescription(rs.getString(4)) ; all.add(product); } rs.close() ; pstmt.close() ; } catch (Exception e) { System.out.println(e) ; throw new Exception("操作中出现错误!!!") ; } finally { dbc.close() ; } return all; } // 模糊查询 }; Struts 2的action: package petstore.action.redirect; import java.util.HashMap; import java.util.LinkedList; import java.util.List; import java.util.Map; import com.opensymphony.xwork2.ActionContext; import com.opensymphony.xwork2.ActionSupport; import petstore.dao.CategoryDao; import petstore.dao.ProductDao; import petstore.model.Category; import petstore.model.Product; public class ItemAddRedirectAction extends ActionSupport { private static final long serialVersionUID = 1L; public static final String GLOBAL_CATEGORY = "global_category_list"; // 宠物大类列表 public static final String GLOBAL_DOUBLE_LIST = "global_double_list"; // 宠物类列表 private ProductDao productDao=new ProductDao(); private CategoryDao categoryDao=new CategoryDao() ; private List<Category> categorys; @SuppressWarnings("unchecked") private Map doubleMap = new HashMap(); public List<Category> getCategorys() { return categorys; } public void setCategorys(List<Category> categorys) { this.categorys = categorys; } @SuppressWarnings("unchecked") public Map getDoubleMap() { return doubleMap; } @SuppressWarnings("unchecked") public void setDoubleMap(Map doubleMap) { this.doubleMap = doubleMap; } public void setProductDao(ProductDao productDao) { this.productDao = productDao; } public void setCategoryDao(CategoryDao categoryDao) { this.categoryDao = categoryDao; } @SuppressWarnings("unchecked") @Override public String execute() throws Exception { //优化数据库性能 categorys = (List) ActionContext.getContext().getSession().get( GLOBAL_CATEGORY); if (categorys == null) { categorys = categoryDao.findAll(); ActionContext.getContext().getSession().put(GLOBAL_CATEGORY, categorys); } for (int i = 0; i < categorys.size(); i++) { List<Product> products = productDao .findProductByCategoryId(categorys.get(i).getCategoryId()); List c = new LinkedList(); for (int j = 0; j < products.size(); j++) { c.add(products.get(j)); } doubleMap.put(categorys.get(i), c); } return SUCCESS; } } itemAdd.jsp文件:
<%@ page language="java" contentType="text/html; charset=GB18030" pageEncoding="GB18030"%> <%@ taglib prefix="s" uri="/struts-tags"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=GB18030"> <title><s:text name="additem_page" /></title> </head> <body> <s:actionerror /> <p id="title"> 增加宠物 </p> <s:form action="itemAddAction" enctype="multipart/form-data" name="itemAdd" id="itemAdd"> <s:doubleselect name="category" list="categorys" doubleName="product" doubleList="doubleMap.get(top)"></s:doubleselect> <s:submit key="submit"></s:submit><s:reset key="reset"></s:reset> </s:form> </body> </html> 需要注意: <s:doubleselect name="category" list="categorys" doubleName="product" doubleList="doubleMap.get(top)"></s:doubleselect> doubleselect中的list属性是一个Arraylist doublelist属性是一个HashMap 和ItemAddRedirectAction类中的下列代码对应 private List<Category> categorys; private Map doubleMap = new HashMap();
struts.xml <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <include file="struts-default.xml"/> <package name="struts2" extends="struts-default"> <action name="directItemAdd" class="petstore.action.redirect.ItemAddRedirectAction"> <result>/itemAdd.jsp</result> </action> </package> </struts>
web.xml <?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <filter> <filter-name>struts2</filter-name> <filter-class>org.apache.struts2.dispatcher.FilterDispatcher </filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app> 运行图片:用iE才能看到
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发表时间:2008-09-01
用iBatis吧,数据访问会简单很多
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发表时间:2009-04-25
我做的怎么报错呢。是网页上有个错误
找不到哪的错。代码如下 items = this.getItemManager().queryAll(); for(int i=0; i<items.size(); i++){ item = items.get(i); subitems = item.getSubitems(); List<Subitem> c = new LinkedList<Subitem>(); Iterator iter = subitems.iterator(); while(iter.hasNext()){ c.add((Subitem)iter.next()); } doubleMap.put(items.get(i), c); } return SUCCESS; <s:doubleselect doubleList="doubleMap.get(top)" doubleName="subitemname" doubleListValue="subitemname" name="itemname" list="items" listValue="itemname" formName="form1"></s:doubleselect> |
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发表时间:2009-04-26
itemAdd.jsp页面里,form action="itemAddAction",而struts.xml里,action name="directItemAdd",两个action名字不一样,不知道是不是楼主写错了?
另在itemAdd.jsp里,我试的时候,页面有错误:The attribute prefix COLOR does not correspond to any imported tag library。我把span都删除后,又报这个错:org.apache.jasper.JasperException: tag 'doubleselect', field 'list', name 'category': The requested list key 'categorys' could not be resolved as a collection/array/map/enumeration/iterator type 我用的是myeclipse做的。 BTW:用IE还是看不到图,不知道是不是自己RP有问题了 |
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