作者：zergman
email: zergman@chinaasp.com
日期：6/12/2001 1:15:04 PM
發布者:flyfox 

Tip:通過socket訪問數據庫,分 Clinet, Display,sqlServer三個類 

Client.java 

import java.awt.*; 
import java.io.*; 
import java.net.*; 
import java.applet.*; 

public class Client extends Applet 
{ 
public TextArea chat_txt; 
private TextField sql_txt; 
private Button connect,execute; 
private Socket soc= null; 
private PrintStream ps= null; 
Listen listen; 

public void init() 
{ 
chat_txt= new TextArea(); 
sql_txt= new TextField(20); 
connect= new Button("Connect"); 
execute= new Button("Execute"); 
execute.disable(); 

Panel pp= new Panel(); 
pp.setLayout(new FlowLayout()); 
pp.add(sql_txt); 
pp.add(connect); 
pp.add(execute); 

add("North",pp); 
add("Center",chat_txt); 
} 

public boolean action(Event evt,Object obj) 
{ 
if(evt.target instanceof Button) 
{ 
String label= (String)obj; 
if(label.equals("Connect")) 
{ 

try{ 
soc= new Socket(InetAddress.getLocalHost(),4700); 
ps= new PrintStream(soc.getOutputStream()); 
ps.println("HELLO"); 
ps.flush(); 
listen= new Listen(this,soc); 
listen.start(); 
}catch(Exception e) 
{ 
chat_txt.setText(e.toString()); 
disconnect(); 
} 
connect.setLabel("Disconnect"); 
execute.enable(); 
}else if(label.equals("Disconnect")) 
disconnect(); 
else if(label.equals("Execute")) 
{ 
if(sql_txt.getText()!= null) 
{ 
ps.println("FIND"); 
ps.flush(); 
ps.println(sql_txt.getText()); 
ps.flush(); 
} 
} 
} 
return false; 
} 

public void disconnect() 
{ 
if(soc!= null) 
{ 
try{ 
listen.stop(); 
ps.println("QUIT"); 
ps.flush(); 
soc.close(); 
}catch(Exception e){} 
finally{ 
listen.stop(); 
listen= null; 
soc= null; 
} 
execute.disable(); 
connect.setLabel("Disconnect"); 
} 
} 
} 

class Listen extends Thread 
{ 
Socket socket= null; 
DataInputStream dis= null; 
Client parent= null; 

public Listen(Client p,Socket s) 
{ 
parent= p; 
socket= s; 
try{ 
dis= new DataInputStream(socket.getInputStream()); 
}catch(Exception e){} 
} 

public void run() 
{ 
String line= null; 

while(true) 
{ 
try{ 
line= dis.readLine(); 
}catch(Exception e){} 
if(line!= null) 
parent.chat_txt.appendText(line); 
} 
} 
} 


Display.java 

/******************************************** 
格式化輸出數據庫記錄,出自<<使用java進行SQL數據庫程序設計>> 
返回值為格式化的字符串 
********************************************/ 
import java.sql.*; 

class Display extends Object 
{ 
ResultSet theResultSet; 
String theResult; 

public void display() 
{} 

public void setResult(ResultSet result) 
{ 
theResultSet= result; 
} 

public String getString() 
throws SQLException,NoClassDefFoundError 
{ 
theResult= ""; 
ResultSetMetaData metaData= theResultSet.getMetaData(); 
int colcount = metaData.getColumnCount(); 
int colSize[]= new int[colcount]; 
String colLabel[]= new String[colcount]; 
int colType[]= new int[colcount]; 
String colTName[]= new String[colcount]; 
int colPrec[]= new int[colcount]; 
int colScale[]= new int[colcount]; 

theResult +="\n"; 
for(int i= 1;i<= colcount;i++) 
{ 
colSize[i-1] = metaData.getColumnDisplaySize(i); 
colLabel[i-1]= metaData.getColumnLabel(i); 
colType[i-1] = metaData.getColumnType(i); 
colTName[i-1]= metaData.getColumnTypeName(i); 
colPrec[i-1] = metaData.getPrecision(i); 
colScale[i-1]= metaData.getScale(i); 

if(colSize[i-1]<1+ colLabel[i-1].length()) 
colSize[i-1]= 1+colLabel[i-1].length(); 
theResult+= rightPad(colLabel[i-1],colSize[i-1]); 
} 

theResult +="\n\n"; 
int row= 0; 

while(theResultSet.next()) 
{ 
row++; 
for(int i=1;i<= colcount;i++) 
{ 
String colvalue= theResultSet.getString(i); 
if(colvalue== null) 
colvalue=""; 
theResult+= rightPad(colvalue,colSize[i-1]); 
} 
theResult+="\n"; 
} 
theResult+="\n(" +row+ "rows included)\n"; 
return theResult; 
} 

private String rightPad(String s,int len) 
{ 
int curlen= s.length(); 
if(curlen>len) 
return repString("*",len); 
return (s+repString(" ",(len-curlen))); 
} 

private String repString(String s,int times) 
{ 
String result=""; 
for(int i=0;i<times;i++) 
result+= s; 
return result; 
} 
} 


sqlServer.java 

import java.awt.*; 
import java.sql.*; 
import java.io.*; 
import java.net.*; 
import Display; 

public class sqlServer 
{ 
public static void main(String[] args) 
{ 
System.out.println("Waiting for connection"); 

try{ 
ServerSocket session= new ServerSocket(4700); 
handleRequests handler= null; 
System.out.println("Waiting for connection"); 
while(true) 
{ 
Socket socket= null; 
socket= session.accept(); 
if(socket== null) 
continue; 
System.out.println("Connection made"); 
handler= new handleRequests(socket); 
handler.start(); 
} 
}catch(Exception e) 
{ 
System.out.println("客戶連接失敗"+e); 
} 
} 
} 

class handleRequests extends Thread 
{ 
private DataInputStream in= null; 
private PrintStream out= null; 
private Socket socket= null; 

Connection theConnection= null; 
Statement theStatement= null; 
ResultSet theResultSet= null; 
Display display= null; 

public handleRequests(Socket s) 
throws IOException 
{ 
socket= s; 
in= new DataInputStream(socket.getInputStream()); 
out= new PrintStream(socket.getOutputStream()); 
} 

public void openConnection() 
{ 
try{ 
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); 
if(theConnection!= null) 
theConnection.close(); 
theConnection= DriverManager.getConnection("jdbc:odbc:test","admin","1234"); 
theStatement= theConnection.createStatement(); 
display= new Display(); 
}catch(Exception e) 
{ 
System.out.println(e); 
} 
} 

public void run() 
{ 
openConnection(); 
try{ 
String line= null; 
while(true) 
{ 
line = in.readLine(); 
if(line!= null) 
line= line.trim(); 
if(line.equals("FIND")) 
{ 
line = in.readLine(); 
line= line.trim(); 
theResultSet= theStatement.executeQuery(line); 
display.setResult(theResultSet); 
out.print(display.getString()); 
out.flush(); 
} 
if(line.equals("QUIT")) 
break; 
if(line.equals("HELLO")) 
{ 
out.println("Welcome to join us"); 
out.flush(); 
} 
} 
in.close(); 
out.close(); 
socket.close(); 
}catch(Exception e) 
{ 
System.out.println(e); 
} 
} 
}