Flex4之DataGrid增删改同步数据库及页面数据示例总结_JAVA_编程开发_程序员俱乐部

有关Flex的DataGrid文章的确不少，都是零零碎碎的，目前还没有发现有个完整的例子供网友参考，这次我花了两天时间做了下Flex关于DataGrid一个指标数据管理系统，当然设计到的mxml会很多，大都是与DataGrid相关，我就抽取最常用的DataGrid的增删改同步数据库及页面数据来讲解

首先整理下思路，首先无论是删除还是修改，必须得获取当前行所在的记录，那么可以设置个全局变量，当DataGrid的itemClick事件出发时将选中的行赋给全局变量

[Bindable]public var acItemsSelected:Object;;

//事件方法

?protected function myGrid_itemClickHandler(event:ListEvent):void
???{
????acItemsSelected = myGrid.selectedItem;?
???}

这样的话就可以获得了当前选中的对象了

如果删除和修改的话，通常传到后台的肯定含有对象的ID项，那么这个ID是怎么获取的呢，通过acItemsSelected.xxxId能获取，那么这个xxxId必须是在DataGrid中有，设置为不显示就好了，例如我就是这么做的

?<mx:DataGridColumn visible="false" dataField="targetCalId" />

这样的话，要更改的数据等都能通过ID传到后台查询相应对象更改删除了，接下来的事是比较重要的，如果光删除数据库是不行的，页面数据也要保持同步，关于dataGrid也没有好的刷新方法，所以你上网一搜，可能有的人会告诉你对于删除这样做：dataArray.removeItemAt(myGrid.selectedIndex);

增加这样做：dataArray.addItemAt(obj,0);

修改这样做：dataArray.setItemAt(obj,myGrid.selectedIndex);

这里说的dataArray是指的是DataGrid的DataProvider的值集合【当然肯定得声明称全局变量】

这样的写法呢可能你觉得，哎，是对的，其实不然，这并没有真正起到作用，对于FLEX来说缓存是相当大的，不行的话你通过这个修改行记录的属性后，再点这行记录的属性编辑页面发现值根本没改，所以所没有进行二次查询数据库了，利用的是缓存。即便是你调用了初始化查询数据库的那个方法，也是不行的，还是有缓存，最好的做法就是，抛弃上面的三种写法，只需要两步就可以实现刷新，第一初始化DataGrid的那个方法请求必须是URLRequest的，添加一个参数类似于

var u:URLVariables=new URLVariables("temp="+Math.random());

当然不一定非要是temp什么名字都行，然后在返回操作成功提示后调用这个初始化方法，你会发现真的起作用了。

其实建议关于URLRequest传参数的最好带上这个参数，也不费事，可以在很多场合下解决缓存不更新问题

说了这么多其实就是先做好个思想准备，理清思路，下面我就贴上我的一段代码

mxml文件

Xml代码 javascripts/syntaxhighlighter/clipboard_new.swf">?

1. <span?style="font-size:?medium;"><?xml?version="1.0"?encoding="utf-8"?>??
2. <s:TitleWindow?xmlns:fx="http://ns.adobe.com/mxml/2009"???
3. ???????????????xmlns:s="library://ns.adobe.com/flex/spark"???
4. ???????????????xmlns:mx="library://ns.adobe.com/flex/mx"?width="668"?height="326"???
5. ???????????????creationComplete="initComponent()"?????
6. ???????????????title="指标计量单位"??
7. ???????????????fontSize="15"??
8. ???????????????close="closeWindow()">????
9. ??????
10. ????<s:layout>??
11. ????????<s:VerticalLayout?/>??
12. ????</s:layout>??
13. ????<fx:Declarations>??
14. ????????<mx:StringValidator?id="sval_1"?source="{targetTypeName}"?property="text"???
15. ????????????????????????????tooShortError="字符串太短了，请输入最少4个字符.?"???
16. ????????????????????????????tooLongError="字符串太长了，请输入最长20个字符.?"???
17. ????????????????????????????minLength="4"?maxLength="20"???
18. ????????????????????????????trigger="{myButton}"?triggerEvent="click"???
19. ????????????????????????????/>??
20. ????????<mx:StringValidator?id="sval_2"?source="{targetCal}"?property="text"???
21. ????????????????????????????tooShortError="字符串太短了，请输入最少4个字符.?"???
22. ????????????????????????????tooLongError="字符串太长了，请输入最长20个字符.?"???
23. ????????????????????????????minLength="4"?maxLength="20"???
24. ????????????????????????????trigger="{myButton}"?triggerEvent="click"???
25. ????????????????????????????/>??
26. ????</fx:Declarations>??
27. ??????
28. ????<fx:Script>??
29. ????????<![CDATA[?
30. ????????????import?com.adobe.serialization.json.JSON;?
31. ?????????????
32. ????????????import?mx.collections.ArrayCollection;?
33. ????????????import?mx.controls.Alert;?
34. ????????????import?mx.events.CloseEvent;?
35. ????????????import?mx.events.ListEvent;?
36. ????????????import?mx.managers.PopUpManager;?
37. ????????????import?mx.rpc.events.ResultEvent;?
38. ????????????import?mx.utils.URLUtil;?
39. ????????????import?mx.validators.Validator;?
40. ?????????????
41. ????????????import?org.osmf.utils.URL;???
42. ????????????[Bindable]public?static?var?mainApp:DataCenterTargetPreserve?=?null;??????
43. ????????????[Bindable]public?var?gsMyString:String;?????????
44. ????????????[Bindable]public?var?gnMyNumber:Number;?????????
45. ????????????[Bindable]public?var?acItemsSelected:Object;?
46. ????????????[Bindable]?
47. ????????????public?var?dataArray:ArrayCollection;??
48. ?????????????
49. ????????????private?function?initComponent():void???
50. ????????????{???
51. ????????????????var?u:URLVariables=new?URLVariables("temp="+Math.random());?
52. ????????????????var?r:URLRequest=new?URLRequest();?
53. ????????????????r.data=u;?
54. ????????????????r.method=URLRequestMethod.POST;?
55. ????????????????r.url=mainApp.urls+"/findTargetCal.do";?
56. ?????????????????
57. ????????????????var?l:URLLoader=new?URLLoader();?
58. ????????????????l.load(r);?
59. ????????????????l.addEventListener(Event.COMPLETE,?comp2);?
60. ?????????????????
61. ????????????}???
62. ????????????function?comp2(e:Event):void?
63. ????????????{?
64. ????????????????var?l:URLLoader=URLLoader(e.target);?
65. ????????????????var?array:Array=JSON.decode(String(l.data))?as?Array;?
66. ????????????????dataArray=new?ArrayCollection(array);?
67. ????????????????myGrid.dataProvider=dataArray;?
68. ????????????}??
69. ????????????private?function?closeWindow():void???
70. ????????????{???
71. ????????????????PopUpManager.removePopUp(this);???
72. ????????????}//closeWindow???
73. ????????????private?function?showFinalSelection(oEvent:Event):void???
74. ????????????{???
75. ????????????????//mainApp.tiFinalSelection.text?=?oEvent.target.selectedItem.album;???
76. ????????????}//showFinalSelection???
77. ?
78. ????????????protected?function?button1_clickHandler(event:MouseEvent):void?
79. ????????????{?
80. ????????????????PopUpManager.removePopUp(this);???
81. ?????????????????
82. ????????????}?
83. ?
84. ????????????protected?function?button2_clickHandler(event:MouseEvent):void?
85. ????????????{?
86. ?????????????????
87. ????????????????var?all:Array=Validator.validateAll([sval_1,sval_2]);?
88. ????????????????if(all.length==0){?
89. ????????????????var?v:URLVariables=new?URLVariables("targetTypeName="+targetTypeName.text+"&targetCal="+targetCal.text+"&temp="+Math.random());?
90. ????????????????var?r:URLRequest=new?URLRequest();?
91. ????????????????r.url=mainApp.urls+"/addTargetCal.do";?
92. ????????????????r.method=URLRequestMethod.POST;?
93. ????????????????r.data=v;?
94. ????????????????var?l:URLLoader=new?URLLoader();?
95. ????????????????l.load(r);?
96. ????????????????l.addEventListener(Event.COMPLETE,comp);?
97. ????????????????}else{?
98. ??????????????????Alert.show("新增失败");?
99. ????????????????}?
100. ?????????????????
101. ????????????}?
102. ????????????private?function?comp(e:Event):void{?
103. ????????????????var?l:URLLoader?=?URLLoader(e.target);???
104. ????????????????var?o:Object=URLUtil.stringToObject(l.data,";",true);?
105. ????????????????if(o.result=="add"){?
106. ??????????????????Alert.show("新增成功");?
107. ??????????????????var?obj:Object=(JSON.decode(o.datas)?as?Object);?
108. ??????????????????//dataArray.addItemAt(obj,0);?
109. ??????????????????Alert.show(obj.targetCalId);?
110. ????????????????}?
111. ????????????????initComponent();?
112. ?????????????
113. ????????????}?
114. ?
115. ????????????private?function?myClick(evt:CloseEvent):void{?
116. ????????????????//Alert.show("本次要删除的为"+mainDataGrid.selectedIndex);?
117. ????????????????if(evt.detail==Alert.YES){?
118. ????????????????????//Alert.show(acItemsSelected.getItemAt(0).targetId);?
119. ????????????????????var?v:URLVariables?=?new?URLVariables("id="+acItemsSelected.targetCalId+"&temp="+Math.random());?
120. ????????????????????var?r:URLRequest?=?new?URLRequest();???
121. ????????????????????r.url?=mainApp.urls+"/deleteTargetCal.do"?;???
122. ????????????????????r.method?=?URLRequestMethod.POST;???
123. ????????????????????r.data=v;?
124. ????????????????????var?l:URLLoader?=?new?URLLoader();???????????
125. ????????????????????l.load(r);???
126. ?????????????????????
127. ????????????????????//dataArray.removeItemAt(myGrid.selectedIndex);?
128. ????????????????????l.addEventListener(Event.COMPLETE,comp1);?//注册请求完成后?响应获取数据事件方法??
129. ?????????????????????
130. ????????????????}?
131. ????????????}?
132. ????????????private?function?comp1(e:Event):void???
133. ????????????{???
134. ????????????????var?l:URLLoader?=?URLLoader(e.target);?
135. ????????????????var?o:Object?=?URLUtil.stringToObject(l.data,?";",?true);?
136. ????????????????if(o.result=="delete"){?
137. ????????????????????Alert.show("删除成功！","友情提示");?
138. ????????????????}?
139. ????????????????initComponent();?
140. ?????????????????
141. ????????????}??
142. ????????????protected?function?button3_clickHandler(event:MouseEvent):void?
143. ????????????{?
144. ????????????????if(myGrid.selectedItem==null){?
145. ????????????????????Alert.show("请选择一项进行删除","友情提示");?
146. ????????????????}else{?
147. ????????????????????var?dlg_obj:Object=Alert.show("确认删除吗？",?"友情提示！",?Alert.YES|Alert.NO,null,myClick);?
148. ????????????????}?
149. ????????????}?
150. ?
151. ?
152. ????????????protected?function?button4_clickHandler(event:MouseEvent):void?
153. ????????????{?
154. ?????????????????
155. ????????????????if(myGrid.selectedItem==null){?
156. ????????????????????Alert.show("请选择一项进行修订!","友情提示");?
157. ????????????????}else{?
158. ????????????????????var?v:URLVariables?=?new?URLVariables("targetTypeName="+targetTypeName.text+"&targetCal="+targetCal.text+"&id="+acItemsSelected.targetCalId);?
159. ????????????????????var?r:URLRequest?=?new?URLRequest();???
160. ????????????????????r.url?=mainApp.urls+"/updateTargetCal.do";???
161. ????????????????????r.method?=?URLRequestMethod.POST;???
162. ????????????????????r.data?=?v;???
163. ????????????????????var?l:URLLoader?=?new?URLLoader();???????????
164. ????????????????????l.load(r);???
165. ????????????????????l.addEventListener(Event.COMPLETE,comp3);?//注册请求完成后?响应获取数据事件方法??
166. ????????????????}?
167. ????????????}?
168. ????????????private?function?comp3(e:Event):void???
169. ????????????{???
170. ?????????????????
171. ????????????????var?l:URLLoader?=?URLLoader(e.target);???
172. ????????????????var?o:Object?=?URLUtil.stringToObject(l.data,?";",?true);????????
173. ????????????????if(o.result=="update"){?
174. ????????????????????Alert.show("更新成功！","友情提示");?
175. ????????????????????var?obj:Object=(JSON.decode(o.datas)?as?Object);?
176. ????????????????????//dataArray.setItemAt(obj,myGrid.selectedIndex);?
177. ????????????????}else{?
178. ????????????????????Alert.show("操作失败！","友情提示");?
179. ????????????????}?
180. ????????????????initComponent();?
181. ????????????}???
182. ?
183. ????????????protected?function?myGrid_itemClickHandler(event:ListEvent):void?
184. ????????????{?
185. ????????????????acItemsSelected?=myGrid.selectedItem;?
186. ????????????}?
187. ?
188. ????????]]>??
189. ????</fx:Script>??
190. ????<mx:Form?width="651"?height="282">??
191. ????????<mx:DataGrid?width="616"?height="160"?id="myGrid"?itemClick="myGrid_itemClickHandler(event)">??
192. ????????????<mx:columns>??
193. ????????????????<mx:DataGridColumn?headerText="计量名称"?dataField="targetTypeName"/>??
194. ????????????????<mx:DataGridColumn?headerText="计量符号"?dataField="targetCal"/>??
195. ????????????????<mx:DataGridColumn?visible="false"?dataField="targetCalId"?/>??
196. ????????????</mx:columns>??
197. ????????</mx:DataGrid>??
198. ????????<mx:HBox>??
199. ????????????<s:Label??width="33"/>??
200. ????????????<mx:FormItem?label="计量名称"?>??
201. ????????????????<s:TextInput?id="targetTypeName"/>??
202. ????????????</mx:FormItem>??
203. ????????????<mx:FormItem?label="计量符号"?>??
204. ????????????????<s:TextInput?id="targetCal"/>??
205. ????????????</mx:FormItem>??
206. ????????????<mx:FormItem?>??
207. ????????????????<s:Button?label="新增"?id="myButton"?click="button2_clickHandler(event)"?/>??
208. ????????????</mx:FormItem>??
209. ??????????????
210. ????????</mx:HBox>??
211. ????????<mx:FormItem?>??
212. ????????</mx:FormItem>??
213. ??????????
214. ????????<mx:HBox>??
215. ????????????<s:Label??width="250"/>??
216. ????????????<mx:FormItem?>??
217. ????????????????<s:Button?label="删除"?click="button3_clickHandler(event)"/>??
218. ????????????</mx:FormItem>??
219. ????????????<mx:FormItem?>??
220. ????????????????<s:Button?label="修改"?click="button4_clickHandler(event)"/>??
221. ????????????</mx:FormItem>??
222. ????????????<mx:FormItem?>??
223. ????????????????<s:Button?label="刷新"/>??
224. ????????????</mx:FormItem>??
225. ????????????<mx:FormItem?>??
226. ????????????????<s:Button?label="关闭"?click="button1_clickHandler(event)"/>??
227. ????????????</mx:FormItem>??
228. ????????</mx:HBox>??
229. ??????????
230. ????</mx:Form>??
231. </s:TitleWindow>??
232. </span>??

?

关于上面这个程序的mainApp就不用管它，它只是主应用程序而已，细心的可以发现这个是个弹出窗口程序

?关于这个程序的三个Servletet处理类【只贴上关键代码】

FindTargetCalServlet

Java代码 ?

1. <span?style="font-size:?medium;">public?void?doPost(HttpServletRequest?request,?HttpServletResponse?response)??
2. ????????????throws?ServletException,?IOException?{??
3. ????????request.setCharacterEncoding("UTF-8");??
4. ????????TTargetCalDAO?dao=new?TTargetCalDAO();??
5. ????????List<TTargetCal>?cals=dao.findAll();??
6. ????????JSONArray?json?=?JSONArray.fromObject(cals);??
7. ????????String?datas?=?json.toString();??
8. ????????System.out.println(datas);??
9. ????????System.out.println(datas);??
10. ????????response.setCharacterEncoding("UTF-8");??
11. ????????response.getWriter().write(datas);??
12. ??????????
13. ????}</span>??

?

DeleteTargetCalServlet

Java代码 ?

1. <span?style="font-size:?medium;">public?void?doPost(HttpServletRequest?request,?HttpServletResponse?response)??
2. ????????????throws?ServletException,?IOException?{??
3. ????????TTargetCalDAO?dao?=?new?TTargetCalDAO();??
4. ????????String?id?=?request.getParameter("id");??
5. ????????if?(DataOptUtils.isNotNull(id))?{??
6. ????????????TTargetCal?rr?=?dao.findById(Integer.valueOf(id));??
7. ????????????dao.delete(rr);??
8. ????????}??
9. ????????response.setCharacterEncoding("UTF-8");??
10. ????????response.getWriter().write("result=delete");??
11. ??
12. ????}</span>??

?

AddTargetCalServlet

Java代码 ?

1. <span?style="font-size:?medium;">public?void?doPost(HttpServletRequest?request,?HttpServletResponse?response)??
2. ????????????throws?ServletException,?IOException?{??
3. ????????????request.setCharacterEncoding("UTF-8");??
4. ????????????TTargetCalDAO?dao=new?TTargetCalDAO();??
5. ????????????String?targetCal=request.getParameter("targetCal");??
6. ????????????String?targetTypeName=request.getParameter("targetTypeName");??
7. ????????????TTargetCal?cal=new?TTargetCal();??
8. ????????????cal.setTargetCal(targetCal);??
9. ????????????cal.setTargetTypeName(targetTypeName);??
10. ????????????dao.save(cal);??
11. ????????????TTargetCal?re?=dao.findById(dao.findLastId());??
12. ????????????JSONObject?json?=?JSONObject.fromObject(re);??
13. ????????????String?datas?=?json.toString();??
14. ????????????response.getWriter().write("result=add;datas="?+?datas);??
15. ??????????
16. ??
17. ????}</span>??

?

UpdateTargetCalServlet

Java代码 ?

1. <span?style="font-size:?medium;">public?void?doPost(HttpServletRequest?request,?HttpServletResponse?response)??
2. ????????????throws?ServletException,?IOException?{??
3. ?????????request.setCharacterEncoding("UTF-8");??
4. ????????????response.setCharacterEncoding("UTF-8");??
5. ????????????TTargetCalDAO?dao?=?new?TTargetCalDAO();??
6. ????????????String?targetTypeName?=?request.getParameter("targetTypeName");??
7. ????????????String?targetCal?=?request.getParameter("targetCal");??
8. ????????????String?id?=?request.getParameter("id");??
9. ????????????if?(DataOptUtils.isNotNull(id))?{??
10. ????????????????TTargetCal?rr?=?dao.findById(Integer.valueOf(id));??
11. ????????????????if(DataOptUtils.isNotNull(targetCal)){??
12. ????????????????????rr.setTargetCal(targetCal);??
13. ????????????????}??
14. ????????????????if(DataOptUtils.isNotNull(targetTypeName)){??
15. ????????????????????rr.setTargetTypeName(targetTypeName);??
16. ????????????????}??
17. ????????????????dao.merge(rr);??
18. ????????????????TTargetCal?tc?=?dao.findById(rr.getTargetCalId());??
19. ????????????????JSONObject?json?=?JSONObject.fromObject(tc);??
20. ????????????????String?datas?=?json.toString();??
21. ????????????????response.getWriter().write("result=update;datas="?+?datas);??
22. ????????????}??
23. ??????????????
24. ??
25. ????}</span>??

?这里的DataOptUtils是我写的一个数据处理类，判断是否为空什么的

?还有就是TTargetCal

Java代码 ?

1. <span?style="font-size:?medium;">@Entity??
2. @Table(name?=?"t_target_cal",?catalog?=?"sxtele")??
3. public?class?TTargetCal?implements?java.io.Serializable?{??
4. ??
5. ????//?Fields??
6. ??
7. ????private?Integer?targetCalId;??
8. ????private?String?targetCal;??
9. ????private?String?targetTypeName;??
10. ??
11. ????//?Constructors??
12. ??
13. ????/**?default?constructor?*/??
14. ????public?TTargetCal()?{??
15. ????}??
16. ??
17. ????/**?minimal?constructor?*/??
18. ????public?TTargetCal(String?targetCal)?{??
19. ????????this.targetCal?=?targetCal;??
20. ????}??
21. ??
22. ????/**?full?constructor?*/??
23. ????public?TTargetCal(String?targetCal,?String?targetTypeName)?{??
24. ????????this.targetCal?=?targetCal;??
25. ????????this.targetTypeName?=?targetTypeName;??
26. ????}??
27. ??
28. ????//?Property?accessors??
29. ????@Id??
30. ????@GeneratedValue??
31. ????@Column(name?=?"Target_cal_id",?unique?=?true,?nullable?=?false)??
32. ????public?Integer?getTargetCalId()?{??
33. ????????return?this.targetCalId;??
34. ????}??
35. ??
36. ????public?void?setTargetCalId(Integer?targetCalId)?{??
37. ????????this.targetCalId?=?targetCalId;??
38. ????}??
39. ??
40. ????@Column(name?=?"Target_cal",?nullable?=?false,?length?=?50)??
41. ????public?String?getTargetCal()?{??
42. ????????return?this.targetCal;??
43. ????}??
44. ??
45. ????public?void?setTargetCal(String?targetCal)?{??
46. ????????this.targetCal?=?targetCal;??
47. ????}??
48. ??
49. ????@Column(name?=?"Target_type_name",?length?=?50)??
50. ????public?String?getTargetTypeName()?{??
51. ????????return?this.targetTypeName;??
52. ????}??
53. ??
54. ????public?void?setTargetTypeName(String?targetTypeName)?{??
55. ????????this.targetTypeName?=?targetTypeName;??
56. ????}??
57. ??
58. }</span>??

?源地址：http://javacrazyer.iteye.com/blog/742801