WEB程序开发基础-作业3-WEB（JSP）下的JDBC操作

package com.zss.www;

import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;

public class DBconn { 


private Connection conn=null; 
private PreparedStatement stmt=null; 
private ResultSet rs=null; 

public DBconn(){ 


try { 
String driver="com.mysql.jdbc.Driver"; 
String url="jdbc:mysql://localhost:3306/school"; 
String user="root"; 
String password="711109"; 
Class.forName(driver); 
conn = (Connection) DriverManager.getConnection(url,user,password); 
System.out.println("-------连接成功------"); 
} catch(ClassNotFoundException classnotfoundexception) { 
classnotfoundexception.printStackTrace(); 
System.err.println("db: " + classnotfoundexception.getMessage()); 
} catch(SQLException sqlexception) { 
System.err.println("db.getconn(): " + sqlexception.getMessage()); 
} 







} 


public void DBConn(String driver,String url,String user,String password){

try { 
//driver="com.mysql.jdbc.Driver"; 
//url="jdbc:mysql://localhost:3306/school"; 
//user="root"; 
//password="711109"; 
Class.forName(driver); 
conn = (Connection) DriverManager.getConnection(url,user,password); 
System.out.println("-------连接成功------"); 
} catch(ClassNotFoundException classnotfoundexception) { 
classnotfoundexception.printStackTrace(); 
System.err.println("db: " + classnotfoundexception.getMessage()); 
} catch(SQLException sqlexception) { 
System.err.println("db.getconn(): " + sqlexception.getMessage()); 
} 

} 

public void doInsert(String sql) { 
try { 
stmt = (PreparedStatement)conn.prepareStatement(sql); 
int i = stmt.executeUpdate(sql); 
} catch(SQLException sqlexception) { 
System.err.println("db.executeInset:" + sqlexception.getMessage()); 
}finally{ 

} 
} 

public void doDelete(String sql) { 
try { 
stmt = (PreparedStatement)conn.prepareStatement(sql); 
int i = stmt.executeUpdate(sql); 
} catch(SQLException sqlexception) { 
System.err.println("db.executeDelete:" + sqlexception.getMessage()); 
} 
} 

public void doUpdate(String sql) { 
try { 
stmt = (PreparedStatement)conn.prepareStatement(sql); 
int i = stmt.executeUpdate(sql); 
} catch(SQLException sqlexception) { 
System.err.println("db.executeUpdate:" + sqlexception.getMessage()); 
} 
} 

public ResultSet doSelect(String sql) { 
try { 
stmt = (PreparedStatement)conn.prepareStatement(sql); 
rs = stmt.executeQuery(sql); 
System.out.println("取得结果集"); 
} catch(SQLException sqlexception) { 
System.err.println("db.executeQuery: " + sqlexception.getMessage()); 
} 
return rs; 
} 

public void close(ResultSet rs) throws SQLException, Exception { 

if (rs != null) { 
rs.close(); 
rs = null; 
} 

if (stmt != null) { 
stmt.close(); 
stmt = null; 
} 

if (conn != null) { 
conn.close(); 
conn = null; 
} 
} 

public void close() throws SQLException, Exception { 
if (stmt != null) { 
stmt.close(); 
stmt = null; 
} 

if (conn != null) { 
conn.close(); 
conn = null; 
} 
} 

public static void main(String []args) throws Exception { 
DBconn db=new DBconn(); 
ResultSet rs=db.doSelect("select * from dbuser where userNAME='chenjirong'"); 
try {
while(rs.next()) {
System.out.println(rs.getString(1)); 
System.out.println(rs.getString(2)); 
System.out.println(rs.getString(3)); 
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} 

rs.close();
db.close();
} 
}