求APPLET+SERVLET之间通讯简单DOME

搞定了`
现在问题是怎么从APPLET传参数给SERVLET
然后SERVLET根据APPLET传来的参数去查询数据库
然后把数据再返回给APPLWET

构造一个URL地址，然后作为参数传给URLConnection，获得URLConnection的结果流。

URL m_urlServlet = "http:\\xx.xxx.xxx";
URLConnection conn = m_urlServlet.openConnection();
conn.setRequestProperty("Content-type", "application/octet-stream");conn.setUseCaches(false);
conn.setDoOutput(true);
conn.setDoInput(true);ObjectOutputStream ObjOut = new ObjectOutputStream(conn.getOutputStream());
ObjOut.writeObject(ssbSQL);
ObjOut.flush();ObjectInputStream in = new ObjectInputStream(conn.getInputStream());
cmJANResultSet retVal = (cmJANResultSet) in.readObject();ObjOut.close();
in.close();

String urlSuffix = "/foldername/" + getServletName();
URL m_urlServlet = new URL(protocol, host, port, urlSuffix);

谢谢
请问在APPLET和SERVLET两端的具体传递和接受代码怎么写？
比如我在APPLET上面输入北京
然后SERVLET能通过数据库输出一串东西再返回APPLET

applet通过bean保存数据传递的source不是已经给出？

Servlet传送对象给Applet使用
前日,一位朋友与我谈论Servlet与Applet共享Java对象的问题,现发表出来与大家分享,文中瑕癖
之处甚多,望各位指教.
朋友谈论的需求是这样的:他想通过页面上一个Applet呼叫一个服务器Servlet,而从Servlet产生
一个Java对象再传给另外一个Applet,怎么样让Servlet实时地把对象传给Applet这是一个问题,有一个方
案是采用JMS(JavaMessageService),在我以后的文章中会有叙述的.这里我给大家展示一个简单的实现,那
就是让Applet主动访问Servlet,让Servlet返回Java对象.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.
第一步,编写需要传递的对象类
/**
* Class Person just a demo for translate this class to client
* @author:  rookie
* @datetime: 2002-7-26
*/
package exapplet;
import java.io.*;public class Person implements Serializable {//必须实现Serializable接口才能序列化
private String m_Name;
private int  m_Age; public Person() {
  this("",0);
}
public Person(String name,int age) {
  this.m_Name = name;
  this.m_Age = age;
}
public String getName() {
  return m_Name;
}
public int getAge() {
  return m_Age;
} //Serializable接口中声明的方法
private void writeObject(java.io.ObjectOutputStream out)
     throws IOException {
  out.defaultWriteObject();
} //Serializable接口中声明的方法
private void readObject(java.io.ObjectInputStream in)
     throws IOException, ClassNotFoundException {
  in.defaultReadObject();
}  public static void main(String[] args) {
  try {
   Person p = new Person("Liaoyuan",25);
   ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(new File("test.obj")));
   oos.writeObject(p);
   oos.close();
   ObjectInputStream ois = new ObjectInputStream (new FileInputStream(new File("test.obj")));
   Person q = (Person)ois.readObject();
   ois.close();
   System.out.println(q.getName());
   System.out.println(q.getAge());
  } catch(Exception exp) {
   exp.printStackTrace();
  }
}
}

第二步,实现Servlet
package exapplet;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;public class MyServlet extends HttpServlet
{
public void doGet(HttpServletRequest req,HttpServletResponse res)
  throws ServletException,IOException
{
  String fPath = "H:\\XSchool\\WorkingRoom\\exapplet\\src\\java.obj";

  String act = req.getParameter("Action");
  if ( act.equals("UpdateObject") ) {
   //创建更新JavaObject
   Person p = new Person("Liaoyuan",26);
   ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(new File(fPath)));
   oos.writeObject(p);
   oos.close();
   DataOutputStream dos = new DataOutputStream(res.getOutputStream());
   dos.writeBytes("Server Java Object Updated OK!");
   dos.close();
  } else if ( act.equals("GetObject") ) {
   //传回对象给Applet
   res.setContentType("application/octet-stream");
   Person p;
   ObjectInputStream ois = new ObjectInputStream(new FileInputStream(new File(fPath)));
   try {
    p    = (Person)ois.readObject();
   } catch (ClassNotFoundException e) {
    p = new Person();
   }
   ois.close();

   ObjectOutputStream oos = new ObjectOutputStream(res.getOutputStream());
   oos.writeObject(p);
   oos.close();
  }
}
public String getServletInfo()
{
  return "A simple Servlet!";
}
}

第三步,实现呼叫Servlet更新对象的Applet
package exapplet;
import java.awt.*;
import java.applet.*;
import java.io.*;
import java.net.*;
import netscape.javascript.*;public class MyApplet extends java.applet.Applet
{
public void init()
{
}
public void paint(Graphics g)
{} //This method will be call in html
public void invoke() {
  try {
   URL url = new URL("http://rookie:8080/workingroom/exapplet/PostToApplet?Action=UpdateObject");
   URLConnection urlcon = url.openConnection();
   urlcon.connect();

   DataInputStream dis=new DataInputStream(urlcon.getInputStream());
   String txt = dis.readLine();
   dis.close();

   String[] info = new String[]{txt};
   JSObject.getWindow(this).call("alert",info);
  } catch (Exception e) {
  }
}
}

第四步,实现提取对象的Applet
package exapplet;
import java.awt.*;
import java.applet.*;
import java.io.*;
import java.net.*;
import netscape.javascript.*;public class MyAppletB extends java.applet.Applet
{
public void init()
{
}
public void paint(Graphics g)
{} //This method will be call in html
public void invoke() {
  try {
   URL url = new URL("http://rookie:8080/workingroom/exapplet/PostToApplet?Action=GetObject");
   URLConnection urlcon = url.openConnection();
   urlcon.connect();
   ObjectInputStream ois=new ObjectInputStream(urlcon.getInputStream());
   Person p = (Person)ois.readObject();
   ois.close();
   String[] info = new String[]{"Person Info\n\n-Name: "+p.getName()+"\n-Age : "+p.getAge()};
   JSObject.getWindow(this).call("alert",info);
  } catch (Exception e) {
  }
}
}第五步,配制WebServer(我用的是Tomcat

第五步,配制WebServer(我用的是Tomcat4.0)
拷贝编译后的MyServlet.class到相应目录下,
编辑对应的web.xml文件,确保下面的内容正确
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//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>第六步,编写html文件
呼叫更新的html
<HTML>
<HEAD>
<TITLE> New Document For Using Applet Call Servlet Update Java Object</TITLE>
</HEAD><BODY>
Hello This is a Test!<br>
<APPLET id="obj_applet" align=center code="exapplet.MyApplet" codeBase="." width=400 height=300 name="obj_applet" archive="BV7RFD3P.ZIP"></APPLET>
<Input type=button value="CallAppletMethod" onclick="callApplet()">
<Script language=javascript>
function callApplet()
{
obj_applet.invoke();
}
</Script>
</BODY>
</HTML>提取对象的html
<HTML>
<HEAD>
<TITLE> New Document For Using Applet </TITLE>
</HEAD><BODY>
Hello This is a Test!<br>
<APPLET id="obj_applet" align=center code="exapplet.MyAppletB" codeBase="." width=400 height=300 name="obj_applet" archive="BV7RFD3P.ZIP"></APPLET>
<Input type=button value="CallAppletMethod" onclick="callApplet()">
<Script language=javascript>
function callApplet()
{
obj_applet.invoke();
}
</Script>
</BODY>
</HTML>

to：java小菜鸟多谢了`
  从servlet传递对象给applet好实现。现在问题是我要通过applet传递一个参数给servlet
或者是一个查询语句。然后servlet根据applet传过来的查询语句去查数据库，然后把结果再返回给servlet
  我想首先在客户端建立连接，然后得到OutputStream
接着用ObjectOutputSttream写对象，而servlet端则需要通过request.getInputStream()得到输入流，然后读出内容，关闭输入流，然后建立输出流，写输入流，然后关闭！而客户端要再次接收这个服务器端的输出流，读完内容后关闭。客户端即有输出流又有输入流。
  现在我想请教高手如何实现代码！！
  万分感谢~

上面一句话写错了：应该是把结果再返回给applet

上面只是从servlet传了个对象给applet并显示出来
不是一个结果集而且也没applet传送给servlet信息

request.getParameter()方法也许对你有帮助。

request.getParameter()是传递一个参数
我是想要返回一个结果集
这该如何

调试易

求APPLET+SERVLET之间通讯简单DOME

解决方案 »