实现Applet与Servlet之间进行通讯的简单实例
Servlet传送查询记录集给Applet
这篇文章是继<<Servlet传送对象给Applet使用>>后,征对网友的特殊问题写的又一个实例.
现发表出来与大家分享,文中瑕癖之处甚多,望各位指教.
这个问题在csdn上已经有讨论了http://www.csdn.net/expert/topic/971/971710.xml.
具体的需求就不讲了,这里把我的实现步骤详细写下,与<<Servlet传送对象给Applet使用>>中提到的方法
一样.用到的CachedRowSet可以到
http://java.sun.com//Download4?userid=zlyperson&platform=zip&button=continue&config-file=rowset-1_0-ea4.config
去下.还有一个netscape的包,在C:\WINNT\java\Packages\0S0W0NFX.ZIP中.
我也把所需要的包及我的实现代码打成了包,其中包扩了CachedRowSet&netscape&本文.
http://63.210.240.215/rookieport/rowset.jar
下面给出全部代码和配置,其中Applet部分涵盖
了Javascript与Applet的互相调用,对于该部分不感兴趣的朋友可以复略.
<pre>
第一步,实现Servlet
packageexapplet;
importjava.io.*;
importjava.sql.*;
importjavax.sql.*;
importsun.jdbc.rowset.*;
importjavax.servlet.*;
importjavax.servlet.http.*;
publicclassMyServletextendsHttpServlet
{
static{
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
}catch(Exceptione){
e.printStackTrace();
}
}
publicvoiddoGet(HttpServletRequestreq,HttpServletResponseres)
throwsServletException,IOException
{
try{
Connectiondbconn=DriverManager.getConnection("jdbc:odbc:BlueSite");
Statementstmt=dbconn.createStatement();
Stringdbsql=req.getParameter("DBSQL");
ResultSetdbrest=stmt.executeQuery(dbsql);
CachedRowSetcrs=newCachedRowSet();
crs.populate(dbrest);
dbrest.close();
stmt.close();
dbconn.close();
//传回对象给Applet
res.setContentType("application/octet-stream");
ObjectOutputStreamoos=newObjectOutputStream(res.getOutputStream());
oos.writeObject(crs);
oos.close();
}catch(Exceptionexp){
exp.printStackTrace();
}
}
publicStringgetServletInfo()
{
return"AsimpleServlet!";
}
}
第二步,实现提取对象的Applet
packageexapplet;
importjava.awt.*;
importjava.applet.*;
importjava.io.*;
importjava.net.*;
importjavax.sql.*;
importsun.jdbc.rowset.*;
importnetscape.javascript.*;
publicclassMyAppletBextendsjava.applet.Applet
{
publicvoidinit()
{
}
publicvoidpaint(Graphicsg)
{}
//Thismethodwillbecallinhtml
publicvoidinvoke(){
try{
URLurl=newURL("http://Liaoyuan:8080/WorkingRoom/exapplet/PostToApplet?DBSQL=Select%20TopicName,TopicName,TopicName%20from%20Topic");
//注意url中的空个用%20替代.
URLConnectionurlcon=url.openConnection();
urlcon.connect();
ObjectInputStreamois=newObjectInputStream(urlcon.getInputStream());
CachedRowSetcrs=(CachedRowSet)ois.readObject();
ois.close();
while(crs.next()){
JSObject.getWindow(this).call("alert",newString[]{crs.getString(1)});
}
crs.close();
}catch(Exceptione){
}
}
}
第三步,配制WebServer(我用的是Tomcat4.0)
拷贝编译后的MyServlet.class到相应目录下,或者下载我打的包到WEB-INF\lib下
编辑对应的web.xml文件,确保下面的内容正确
<?xmlversion="1.0"encoding="UTF-8"?>
<!DOCTYPEweb-appPUBLIC"-//SunMicrosystems,Inc.//DTDWebApplication2.2//EN""http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
<web-app>
<servlet>
<servlet-name>PostToApplet</servlet-name>
<servlet-class>exapplet.MyServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>
PostToApplet
</servlet-name>
<url-pattern>
/exapplet/PostToApplet
</url-pattern>
</servlet-mapping>
</web-app>
第四步,编写html文件
提取对象的html
<HTML>
<HEAD>
<TITLE>NewDocumentForUsingApplet</TITLE>
</HEAD>
<BODY>
HelloThisisaTest!<br>
<APPLETid="obj_applet"align=centercode="exapplet.MyAppletB"codeBase="."width=400height=300name="obj_applet"archive="BV7RFD3P.ZIP"></APPLET>
<Inputtype=buttonvalue="CallAppletMethod"onclick="callApplet()">
<Scriptlanguage=javascript>
functioncallApplet()
{
obj_applet.invoke();
}
</Script>
</BODY>
</HTML>
</pre>