JSP下通过socket访问数据库
作者:不详
通过socket访问数据库,分 Clinet, Display,sqlServer三个类
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
/********************************************
格式化输出数据库记录,出自<<使用java进行SQL数据库程序设计>>
返回值为格式化的字符串
********************************************/
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
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(\"客户连接失败\"+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);
}
}
}
发布人:netbull 来自:LinuxAid