仿SQLPLUS

实现sqlplus的功能，代码如下：
import java.sql.*;
import java.io.*;

public class SQLTools{
public static void main(String[] args){
StringBuffer info=new StringBuffer();
info.append("-------read me--------\n");
info.append("commit;---excute con.commit();---\n");
info.append("rollback;---excute con.rollback();---\n");
info.append("sqlString;---excute sql command;---\n");
info.append("quit;---excute con.commit() and quit program---\n");
info.append("-----------end-----------\n");
System.out.println(info.toString());
Connection con= null;
while((con=getConnection())==null){}
try{
con.setAutoCommit(false);
StringBuffer sb=new StringBuffer();
String cmd="";
boolean flag=true;
int c=0;
String message="";
while(flag){

if(c++==0){
message="SQLTools-> ";
}else{
message=c+"-> ";
}
sb.append(prompt(message));
cmd=sb.toString().trim();
if(cmd.endsWith(";")){
String sql=cmd.substring(0,cmd.length()-1);

if("quit".equals(sql)){
flag=false;
con.commit();
sb=new StringBuffer();
c=0;
}else if("commit".equals(sql)){
con.commit();
sb=new StringBuffer();
c=0;
}else if("rollback".equals(sql)){
con.rollback();
sb=new StringBuffer();
c=0;
}else{
System.out.println(sql);
execute(sql,con);
sb=new StringBuffer();
c=0;
}
}
}

}catch(Exception e){System.out.println("rollback");
try{if(con!=null)con.rollback();
}catch(Exception e3){e3.printStackTrace();}
}
finally{JdbcUtil.release(con);}
}
public static Connection getConnection(){

String message="url:\n";
String url=prompt(message);
message="username:\n";
String username=prompt(message);
message="password:\n";
String pwd=prompt(message);
Connection con=null;
try{
con=DriverManager.getConnection(url,username,pwd);
}catch(Exception e){System.out.println("->connection failed");}
return con;
}
public static String prompt(String message){
BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
System.out.println(message);
String input="";
try{
input=in.readLine();
}catch(Exception e){e.printStackTrace();}
return input;
}
public static void execute(String sql,Connection con)throws Exception{
int c=0;
Statement stmt=null;
ResultSet rs=null;
try{
stmt=con.createStatement();
if(stmt.execute(sql)){
rs=stmt.getResultSet();
JdbcUtil.printRs(rs);
}else{
c=stmt.getUpdateCount();
System.out.println("update succefully!"+c);
}
}catch(Exception e){System.out.println("database manipulation failed!");}
finally{JdbcUtil.release(rs,stmt,null);}

}
}