做完实验，来个小结。
【实验原理和步骤】
1. 定义学生成绩查询或教师信息查询的远程接口
2.
实现服务器端软件(程序):设计远程接口的实现类和服务器对象类,在服务器
上启动目录服务,并注册远程对象,供客户端访问。远程接口的实现类要从本地读取
数据信息(成绩或教师信息),数据信息可以存储在文件或数据库中。
3.
实现客户端软件(程序):实现访问远程对象的客户程序。
【方案设计】
1)编写 RMI 中的接口 public interface GetScoreInterface extends
Remote;
2)编写接口实现方案 public class GetScoreImpl extends UnicastRemoteObject
implements
GetScoreInterface,在此类中,完成对数据库的访问,获得需要的信息,并返回给客户端;
3)编写服务器端程序
public class rmi_server;
4)编写客户端程序 public class rmi_client;
5)用 rmic 命令生成
stub 文件后,对程序进行运行调试。
【实验环境】
ubuntu 12.04
java version "1.7.0_17"
mysql Ver 14.14 Distrib
5.5.37, for debian-linux-gnu (i686) using readline 6.2
Eclipse Platform
Version: 4.2.1
上面是从实验报告中直接复制粘贴过来的，下面说一些小细节：
1）RMI网络编程提供了各种接口，调用一套函数完后，就算写完了，真是清晰明了啊～
2）程序运行有一套安全机制，具体的我没深究=。=还有一堆实验要写。。。女神原谅我现在犯个懒先吧。。。
3）没了=。=下面给源码
interface GetScoreInterface extends Remote:
import java.rmi.*;
import java.sql.SQLException;/**
* This remote method return the students score
* @author Alex <[email protected]>
*
*/public interface GetScoreInterface extends Remote{
public String getScore(String sno)throws RemoteException,SQLException;
}
class GetScoreImpl extends UnicastRemoteObject implements
GetScoreInterface:
import java.rmi.*;
import java.rmi.server.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;/**
* This class implement the interface GetScoreInterface
* @author Alex <[email protected]>
*
*/
public class GetScoreImpl extends UnicastRemoteObject implements GetScoreInterface{String url="jdbc:mysql://localhost:3306/db_exam?&setUnicode=true&characterEncoding=utf-8";
String driver="com.mysql.jdbc.Driver";
Connection con=null;
private String usr="exam_admin";
private String psw="qaz123";
public GetScoreImpl() throws RemoteException{
super();
}/**
* Implement the interface abstract method getScore
*/
public String getScore(String sno)throws RemoteException,SQLException{
String scores="";
String sql=new String("select exam_name,mark from designs natural join marks where sno="+sno+";");
ResultSet rs=null;
try{
Class.forName(driver);
con=DriverManager.getConnection(url , usr, psw);
Statement st=con.createStatement();
rs=st.executeQuery(sql);while(rs.next()){
//System.out.print(rs.getString(1)+"\t"+rs.getString(2));
scores+=rs.getString(1)+"\t"+rs.getString(2)+"\n";
}}catch(SQLException e){
System.out.print("Exception in GetScoreImpl"+e.getMessage());
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return scores;
}/*
public static void main(String[] a) throws RemoteException, SQLException{
GetScoreImpl aaa=new GetScoreImpl();
String kkk=aaa.getScore("20110012");
System.out.print(kkk);}*/
}
View
Code
rmi_client:
import java.io.*;
import java.rmi.*;
/**
* License: GPL
* Description: RMI client which request the scores of the student whose number was given
* @author Alex <[email protected]>
*
*/public class rmi_client {
public static void main(String[] args){
try{
int RMIPort;
//String hostname;
InputStreamReader is=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(is);
//System.out.println("Enter the host name");
//hostname=br.readLine();
System.out.println("Enter the port number");
RMIPort=Integer.parseInt(br.readLine().trim());
String registryURL="rmi://localhost:"+RMIPort+"/GetScore";
GetScoreInterface kkk=(GetScoreInterface)Naming.lookup(registryURL);
System.out.println("Look up completed");
System.out.println("Enter the student number of which you want to check marks");
String sno=br.readLine().trim();
String score=kkk.getScore(sno);
System.out.println(score);}catch(Exception e){
System.out.println("Exception in rmi_client main: "+e.getMessage());
}
}
}
rmi_server:
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;/**
* License: GPL
* Description: RMI server which returns the scores of the student whose number was given
* @author Alex <[email protected]>
*
*/public class rmi_server {
public static void main(String[] args){
InputStreamReader is=new InputStreamReader(System.in);
BufferedReader br=new BufferedReader(is);
String registryURL;
int portNum;
try{
System.out.println("Enter RMIregistry porn number:");
portNum=Integer.parseInt((br.readLine()).trim());
registryURL="rmi://localhost:"+new Integer(portNum).toString()+"/GetScore";
register(registryURL,portNum);
GetScoreImpl exportedObj=new GetScoreImpl();
Naming.rebind(registryURL, exportedObj);
System.out.println("GetSocre server ready");
}catch(Exception e){
System.out.println("Exception in rmi_server main:"+e.getMessage());
}}
/**
* This method register a RMI local host
*/
public static void register(String registryURL,int RMIPortNum)throws RemoteException, MalformedURLException{
try{
Registry registry=LocateRegistry.getRegistry(RMIPortNum);
registry.list();}catch(RemoteException e){
System.out.println("RMI registry cannot be located port "+RMIPortNum);
LocateRegistry.createRegistry(RMIPortNum);
System.out.println("RMI registry created at port "+RMIPortNum);
}
try{
System.out.println("Registry"+registryURL+" contains:");
for(String name:Naming.list(registryURL))
System.out.println(name);
}
catch(MalformedURLException e){
System.out.println("Exception in rmi_server register,MalformedURLException"+e.getMessage());
}
}}
p个小s: 用rmic生成stub文件，在这里是rmic GetScoreImpl (后面不加后缀了)
打完收工=。=接着写下一个实验。。。