Flex 3通过Servlet连接数据库

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本文转自【onlyzhangqin的CSDN Blog http://blog.csdn.net/onlyzhangqin/archive/2008/06/03/2502512.aspx】

本文简单介绍了Flex如何通过servlet连接数据库(Access)。使用的是<mx:HttpService>给后台传递数据的方法。

本文开发使用的软件：

Flex3-eclipse plugin

Tomcat 6.0

microsoft access 2003

Eclipse 3.3

各个软件的安装和使用这里就不介绍了。

首先用Access建立一个名字叫做songs的table.包含了name,singer,lrc,addURL四个field.具体的可以参考附件中附带的access文件。关于Access部署参考：Java连接access数据库 .

其次新建一个mxml文件：Hello.mxml 。具体代码如下：

<?xmlversion="1.0"encoding="utf-8"?>
<mx:Applicationxmlns:mx="http://www.adobe.com/2006/mxml"layout="absolute"
creationComplete="feedRequest.send()">
<mx:HTTPServiceid="feedRequest"
url="http://localhost:8080/flexweb/HelloWorld"
useProxy="false"/>
<mx:Panelx="10"y="10"width="475"height="400"layout="absolute"
title="{dgPosts.selectedItem.name}"color="#1C06F6"fontSize="16">
<mx:DataGridx="20"y="20"id="dgPosts"width="400"dataProvider="{feedRequest.lastResult.songs.song}"fontFamily="TimesNewRoman"fontSize="16">
<mx:columns>
<mx:DataGridColumnheaderText="Name"dataField="name"/>
<mx:DataGridColumnheaderText="Singer"dataField="singer"/>
<mx:DataGridColumnheaderText="URL"dataField="addrURL"/>
</mx:columns>
</mx:DataGrid>
<mx:LinkButtonx="20"y="225"label="下载音乐"click="navigateToURL(newURLRequest(dgPosts.selectedItem.addrURL));"fontFamily="TimesNewRoman"fontSize="20"color="#0B3C0B"/>
<mx:TextAreax="20"y="175"width="400"text="{dgPosts.selectedItem.lrc}"fontFamily="TimesNewRoman"fontSize="16"/>
</mx:Panel>
</mx:Application>

<?xmlversion="1.0"encoding="utf-8"?>
<mx:Applicationxmlns:mx="http://www.adobe.com/2006/mxml"layout="absolute"
creationComplete="feedRequest.send()">
<mx:HTTPServiceid="feedRequest"
url="http://localhost:8080/flexweb/HelloWorld"
useProxy="false"/>
<mx:Panelx="10"y="10"width="475"height="400"layout="absolute"
title="{dgPosts.selectedItem.name}"color="#1C06F6"fontSize="16">
<mx:DataGridx="20"y="20"id="dgPosts"width="400"dataProvider="{feedRequest.lastResult.songs.song}"fontFamily="TimesNewRoman"fontSize="16">
<mx:columns>
<mx:DataGridColumnheaderText="Name"dataField="name"/>
<mx:DataGridColumnheaderText="Singer"dataField="singer"/>
<mx:DataGridColumnheaderText="URL"dataField="addrURL"/>
</mx:columns>
</mx:DataGrid>
<mx:LinkButtonx="20"y="225"label="下载音乐"click="navigateToURL(newURLRequest(dgPosts.selectedItem.addrURL));"fontFamily="TimesNewRoman"fontSize="20"color="#0B3C0B"/>
<mx:TextAreax="20"y="175"width="400"text="{dgPosts.selectedItem.lrc}"fontFamily="TimesNewRoman"fontSize="16"/>
</mx:Panel>
</mx:Application>

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"
     creationComplete="feedRequest.send()" >
   <mx:HTTPService id="feedRequest"
       url="http://localhost:8080/flexweb/HelloWorld"
       useProxy="false" />
    <mx:Panel x="10" y="10" width="475" height="400" layout="absolute"
        title="{dgPosts.selectedItem.name}" color="#1C06F6" fontSize="16">
    <mx:DataGrid x="20" y="20" id="dgPosts" width="400" dataProvider="{feedRequest.lastResult.songs.song}" fontFamily="Times New Roman" fontSize="16">
       <mx:columns>
         <mx:DataGridColumn headerText="Name" dataField="name"/>
         <mx:DataGridColumn headerText="Singer" dataField="singer"/>
         <mx:DataGridColumn headerText="URL" dataField="addrURL"/>
       </mx:columns>
    </mx:DataGrid>
    <mx:LinkButton x="20" y="225" label="下载音乐" click="navigateToURL(new URLRequest(dgPosts.selectedItem.addrURL));" fontFamily="Times New Roman" fontSize="20" color="#0B3C0B"/>
    <mx:TextArea x="20" y="175" width="400" text="{dgPosts.selectedItem.lrc}" fontFamily="Times New Roman" fontSize="16"/>
   </mx:Panel>
</mx:Application>

保存文件，编译执行。此刻由于没有部署本地服务器来执行http://localhost:8080/flexweb/HelloWorld

所以会出现错误信息，不要紧，我们开始搭建servlet.

servlet的具体代码如下: HelloWorld.java

packagetest;
importjava.io.*;
importjava.sql.Connection;
importjava.sql.DriverManager;
importjava.sql.ResultSet;
importjava.sql.SQLException;
importjava.sql.Statement;

importjavax.servlet.*;
importjavax.servlet.http.*;

publicclassHelloWorldextendsHttpServlet{
publicstaticStringdbDriver="sun.jdbc.odbc.JdbcOdbcDriver";
publicStringconnStr="jdbc:odbc:songs";
publicResultSetrs=null;
publicConnectioncon=null;
publicStatementst=null;
publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{

response.setContentType("text/xml;charset=utf-8");
response.setHeader("Cache-Control","no-cache");
Stringcontent="";
Stringname="";
Stringsinger="";
Stringlrc="";
StringaddrURL="";
try{
Connectioncondb=getConnection();
st=condb.createStatement();
rs=st.executeQuery("select*fromsongs");
while(rs.next()){
name=rs.getString("name");
singer=rs.getString("singer");
lrc=rs.getString("lrc");
addrURL=rs.getString("url");
content+="<song><name>"+name+"</name><singer>"+singer+"</singer><lrc>"+
lrc+"</lrc><addrURL>"+addrURL+"</addrURL></song>";
}
}catch(ClassNotFoundExceptione){
e.printStackTrace();
}catch(SQLExceptione1){
e1.printStackTrace();
}
content="<?xmlversion=/"1.0/"encoding=/"utf-8/"?><songs>"+content;
content+="</songs>";

System.out.println(content);
response.getWriter().write(content);
}
publicConnectiongetConnection()throwsClassNotFoundException{
try{
Class.forName(dbDriver);
System.out.println("Connecttodbsuccessfuly!");
con=DriverManager.getConnection(connStr);

}catch(SQLExceptione){
con=null;
System.err.println(e.getMessage());
}
returncon;
}
}

packagetest;
importjava.io.*;
importjava.sql.Connection;
importjava.sql.DriverManager;
importjava.sql.ResultSet;
importjava.sql.SQLException;
importjava.sql.Statement;

importjavax.servlet.*;
importjavax.servlet.http.*;

publicclassHelloWorldextendsHttpServlet{
publicstaticStringdbDriver="sun.jdbc.odbc.JdbcOdbcDriver";
publicStringconnStr="jdbc:odbc:songs";
publicResultSetrs=null;
publicConnectioncon=null;
publicStatementst=null;
publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{

response.setContentType("text/xml;charset=utf-8");
response.setHeader("Cache-Control","no-cache");
Stringcontent="";
Stringname="";
Stringsinger="";
Stringlrc="";
StringaddrURL="";
try{
Connectioncondb=getConnection();
st=condb.createStatement();
rs=st.executeQuery("select*fromsongs");
while(rs.next()){
name=rs.getString("name");
singer=rs.getString("singer");
lrc=rs.getString("lrc");
addrURL=rs.getString("url");
content+="<song><name>"+name+"</name><singer>"+singer+"</singer><lrc>"+
lrc+"</lrc><addrURL>"+addrURL+"</addrURL></song>";
}
}catch(ClassNotFoundExceptione){
e.printStackTrace();
}catch(SQLExceptione1){
e1.printStackTrace();
}
content="<?xmlversion=/"1.0/"encoding=/"utf-8/"?><songs>"+content;
content+="</songs>";

<Atitle=systemhref="http://www.alimama.com/membersvc/buyadzone/buy_ad_zone.htm?adzoneid=892989"target=_blank>system</A>.out.println(content);
response.getWriter().write(content);
}
publicConnectiongetConnection()throwsClassNotFoundException{
try{
Class.forName(dbDriver);
<Atitle=systemhref="http://www.alimama.com/membersvc/buyadzone/buy_ad_zone.htm?adzoneid=892989"target=_blank>system</A>.out.println("Connecttodbsuccessfuly!");
con=DriverManager.getConnection(connStr);

}catch(SQLExceptione){
con=null;
<Atitle=systemhref="http://www.alimama.com/membersvc/buyadzone/buy_ad_zone.htm?adzoneid=892989"target=_blank>system</A>.err.println(e.getMessage());
}
returncon;
}
}

package test;
import java.io.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.servlet.*;
import javax.servlet.http.*;

public class HelloWorld extends HttpServlet {
    public static String dbDriver ="sun.jdbc.odbc.JdbcOdbcDriver";
    public String connStr ="jdbc:odbc:songs";
    public ResultSet rs =null;
    public Connection con=null;
    public Statement st=null;
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException{

        response.setContentType("text/xml;charset=utf-8");
        response.setHeader("Cache-Control", "no-cache");
        String content = "";
        String name="";
        String singer="";
        String lrc="";
        String addrURL="";
        try{
        Connection condb = getConnection();
        st = condb.createStatement();
        rs=st.executeQuery("select * from songs");
        while(rs.next()){
            name = rs.getString("name");
            singer = rs.getString("singer");
            lrc = rs.getString("lrc");
            addrURL = rs.getString("url");
            content+="<song><name>"+name+"</name><singer>"+singer+"</singer><lrc>"+
             lrc+"</lrc><addrURL>"+addrURL+"</addrURL></song>";
        }
        }catch(ClassNotFoundException e){
            e.printStackTrace();
        }catch( SQLException e1){
            e1.printStackTrace();
        }
        content="<?xml version=/"1.0/" encoding=/"utf-8/"?><songs>"+content;
        content+="</songs>";

        system.out.println(content);
        response.getWriter().write(content);
    }
    public Connection getConnection() throws ClassNotFoundException{
        try{
            Class.forName(dbDriver);
            system.out.println("Connect to db successfuly!");
            con = DriverManager.getConnection(connStr);
            
        }catch(SQLException e){
            con=null;
            system.err.println(e.getMessage());
        }
        return con;
    }
}

关于如何利用Tomcat搭建可执行的servlet程序参考：Servlet平台搭建 这里就不介绍了。上面的servlet程序连接access数据库，取出数据后然后生成XML文件，然后在传给Flex应用程序，显示在GUI界面中。截图：

如果部署程序有问题的话，可以留言交流。

附件下载：Flex3通过Servlet连接数据库

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