写了 一个连接sql的bean可能不是非常好,但可以给参考:
package bbsBean;import java.sql.*;
import java.net.*;
import java.io.*;
import java.util.*;public class QueryData implements Serializable
{
//定义变量
static Connection conn=null;
Statement stmt=null;
ResultSet rs=null;
public QueryData(){}
//建立连接
public static void getConnection(){
try
{
//注册驱动
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
/*建立连接*/
conn=DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;User=sa;Password=manager2000;DatabaseName=bbs"); }
catch (ClassNotFoundException e)
{
e.printStackTrace();
}
catch (SQLException e)
{
e.printStackTrace();
}
}
//关闭数据库
public void closeConnection(){
try
{
if (rs!=null)
{
rs.close();
}
if (stmt!=null)
{
stmt.close();
}
if (conn!=null)
{
conn.close();
}
}
catch (SQLException e)
{
e.printStackTrace();
}
rs=null;
stmt=null;
conn=null;
} //returnResultQuery该方法返回一个得到的记录集,参数为sql语句
public ResultSet returnResultQuery(String sql){
rs=null;
try
{
if (conn==null)
{
getConnection();
}
if(conn!=null){
stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
//执行数据库的查询
rs=stmt.executeQuery(sql);
}
}
catch (SQLException e)
{
e.printStackTrace();
}
return rs;
} //executeUpdate用来更新数据库
//参数为sql语句,成功返回true,失败返回false;
public boolean executeUpdate(String sql){
boolean bupdate=false;
try
{
//判断是否连接
if (conn==null)
{
getConnection();
}
if(conn!=null){
stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
int rowCount=stmt.executeUpdate(sql);
if (rowCount!=0)
{
bupdate=true;
}
}
}
catch (SQLException e)
{
e.printStackTrace();
}
return bupdate;
}
//toChinese方法用于将一个字符串进行中文处理
public static String toChinese(String strValue){
try
{
if (strValue==null)
{
return null;
}
else{
strValue=new String(strValue.getBytes("ISO8856_1"),"GBK");
return strValue;
}
}
catch (Exception e)
{
e.printStackTrace();
return null;
}
}
//测试代码
/* public static void main(String arge[]){
ResultSet r=null;
QueryData q=new QueryData();
r=q.returnResultQuery("select * from liouyan");
try
{
while (r.next())
{
System.out.println(r.getString(2));
}
}
catch (SQLException e)
{
System.out.println("错误");
}
}
*/
}
package bbsBean;import java.sql.*;
import java.net.*;
import java.io.*;
import java.util.*;public class QueryData implements Serializable
{
//定义变量
static Connection conn=null;
Statement stmt=null;
ResultSet rs=null;
public QueryData(){}
//建立连接
public static void getConnection(){
try
{
//注册驱动
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
/*建立连接*/
conn=DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;User=sa;Password=manager2000;DatabaseName=bbs"); }
catch (ClassNotFoundException e)
{
e.printStackTrace();
}
catch (SQLException e)
{
e.printStackTrace();
}
}
//关闭数据库
public void closeConnection(){
try
{
if (rs!=null)
{
rs.close();
}
if (stmt!=null)
{
stmt.close();
}
if (conn!=null)
{
conn.close();
}
}
catch (SQLException e)
{
e.printStackTrace();
}
rs=null;
stmt=null;
conn=null;
} //returnResultQuery该方法返回一个得到的记录集,参数为sql语句
public ResultSet returnResultQuery(String sql){
rs=null;
try
{
if (conn==null)
{
getConnection();
}
if(conn!=null){
stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
//执行数据库的查询
rs=stmt.executeQuery(sql);
}
}
catch (SQLException e)
{
e.printStackTrace();
}
return rs;
} //executeUpdate用来更新数据库
//参数为sql语句,成功返回true,失败返回false;
public boolean executeUpdate(String sql){
boolean bupdate=false;
try
{
//判断是否连接
if (conn==null)
{
getConnection();
}
if(conn!=null){
stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
int rowCount=stmt.executeUpdate(sql);
if (rowCount!=0)
{
bupdate=true;
}
}
}
catch (SQLException e)
{
e.printStackTrace();
}
return bupdate;
}
//toChinese方法用于将一个字符串进行中文处理
public static String toChinese(String strValue){
try
{
if (strValue==null)
{
return null;
}
else{
strValue=new String(strValue.getBytes("ISO8856_1"),"GBK");
return strValue;
}
}
catch (Exception e)
{
e.printStackTrace();
return null;
}
}
//测试代码
/* public static void main(String arge[]){
ResultSet r=null;
QueryData q=new QueryData();
r=q.returnResultQuery("select * from liouyan");
try
{
while (r.next())
{
System.out.println(r.getString(2));
}
}
catch (SQLException e)
{
System.out.println("错误");
}
}
*/
}
package webmail;import java.sql.*;
public class conn
{
String driverName = "org.gjt.mm.mysql.Driver";
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
//String connURL= "jdbc:mysql://localhost:3306/webmail","root",""";
String connURL= "jdbc:mysql://localhost/webmail?user=root&password=root";
public conn()
{
try
{
Class.forName(driverName);
}
catch (java.lang.ClassNotFoundException e)
{
System.err.println("netzero(String): " + e.getMessage());
}
}
public ResultSet executeQuery(String sql) throws SQLException
{
conn = DriverManager.getConnection(connURL);
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
return rs;
} public boolean closeConn()
{
try
{
if (rs!=null) rs.close();
if (stmt!=null) stmt.close();
if (conn!=null) conn.close();
return true;
}
catch ( SQLException ex )
{
System.err.println("closeConn: " + ex.getMessage());
return false;
}
} }
String sDBDriver = "com.microsoft.jdbc.sqlserver.SQLServerDriver";
String sConnStr = "jdbc:microsoft:sqlserver://192.168.0.206:1433;DatabaseName=source_index_db";
Connection conn = null;
ResultSet rs = null;public faq()
{
try {
Class.forName(sDBDriver);
conn = DriverManager.getConnection(sConnStr,"sa","2394232");
}
catch(java.lang.ClassNotFoundException e)
{
System.err.println("faq(): " + e.getMessage());
}
catch(SQLException ex)
{
System.err.println("aq.executeQuery: " + ex.getMessage());
}
}
public ResultSet executeQuery(String sql)
{
rs = null;
try
{
Statement stmt = conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);
rs = stmt.executeQuery(sql);
}
catch(SQLException ex)
{
System.err.println("aq.executeQuery: " + ex.getMessage());
}
return rs;
}
}
package bean;
在JSP中:
<jsp:useBean id="work" scope="page" class="bean.faq" />执行查询:
ResultSet RS = work.executeQuery("SELECT * FROM table_name ");
import java.util.*;
import java.sql.*;
import java.io.*;public class DBBean
{
String sDBDriver = "";//数据库驱动
String sConnStr = "";//数据库连接
String suser = "";//用户名
String spass = "";//密码
String sHint = "";//提示信息
ResultSet rs = null;//结果数据集
Connection conn = null;
Statement stmt = null;
//返回提示信息
public String getHint()
{
return sHint;
}
//设置数据库驱动
public void setDBDriver(String s)
{
sDBDriver = "" + s;
}
//返回数据库驱动
public String getDBDriver()
{
return sDBDriver;
}
//设置数据库连接
public void setConnStr(String s)
{
sConnStr = "" + s;
}
//返回数据库连接
public String getConnStr()
{
return sConnStr;
}
//返回结果数据集
public ResultSet getResultSet()
{
return rs;
}
//初始化数据库
public boolean Initialization(String dbDrive,String dbConn,String user,String pass)
{
sDBDriver = dbDrive;
sConnStr = dbConn;
suser = user;
spass = pass;
try{
Class.forName(sDBDriver);
sHint = "Initialisation sucessfully";
return true;
} catch(java.lang.ClassNotFoundException e)
{
sHint = "Initialisation :" + e.getMessage();
return false;
}
}
//执行SQL语句,返回一个数据集
public ResultSet executeQuery(String sql)
{
rs = null;
try
{
conn = DriverManager.getConnection(sConnStr,suser,spass);
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
}
catch(SQLException ex)
{
sHint = "executeQuery:" + ex.getMessage();
}
return rs;
}
//执行一个sql语句,但不返回数据集
public boolean executeUpdate(String sql)
{
try
{
conn = DriverManager.getConnection(sConnStr,suser,spass);
stmt = conn.createStatement();
stmt.executeUpdate(sql);
return true;
}
catch(SQLException ex)
{
sHint = "executeUpdate;" + ex.getMessage();
return false;
}
}
//正常关闭所有连接
public boolean closeConn()
{
try {
if (rs != null)
rs.close();
if(stmt != null)
stmt.close();
if (conn != null)
conn.close();
return true;
}
catch (SQLException ex)
{
sHint = "closeconn:" + ex.getMessage();
return false;
}
}
}
package k_javaServlet;//建立和数据库的连接
//yxy
//12.9
import java.sql.*;
import java.io.*;
import javax.servlet.http.*;public class k_Connection implements HttpSessionBindingListener, Serializable { private Connection m_con=null;
private String m_className="com.microsoft.jdbc.sqlserver.SQLServerDriver";
private String m_user="sa";
private String m_password=null;
private String m_databaseName="pubs";
private String m_IPAdress="127.0.0.1";
private String m_url="jdbc:microsoft:sqlserver://192.168.0.32:1433;DatabaseName=pubs";
//定义连接字符串
private String m_connectString=null; public k_Connection(){
this.buildConnection();
} public k_Connection(String user,String password,String databasename,String ip){
this.setDatabasePara(user,password,databasename,ip);
this.buildConnection();
} public void setDatabasePara(String user,String password,String databasename,String ip)
{
this.m_user=user;
this.m_password=password;
this.m_databaseName=databasename;
this.m_IPAdress=ip;
this.m_connectString="jdbc:microsoft:sqlserver://"+this.m_IPAdress+":1433;DatabaseName="
+this.m_databaseName;
} public void setURL(String url)
{
this.m_url=url;
} //得到连接字符串
public String getConString()
{
return this.m_connectString;
} //建立一个数据库的连接
private void buildConnection()
{
try{
if(this.m_connectString==null)
this.m_connectString=this.m_url;
Class.forName(this.m_className);
this.m_con=DriverManager.getConnection(this.m_connectString,this.m_user,this.m_password);
}
catch(Exception ex)
{
System.out.println(ex.toString());
}
} public void valueBound(HttpSessionBindingEvent event) {
/**@todo Implement this javax.servlet.http.HttpSessionBindingListener method*/
} public void valueUnbound(HttpSessionBindingEvent event) {
/**@todo Implement this javax.servlet.http.HttpSessionBindingListener method*/
if(this.m_con!=null)
this.close();
} public Connection getConnection()
{
if(this.m_con==null)
this.buildConnection();
return this.m_con;
} public void close()
{
try{
this.m_con.close();
this.m_con=null;
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
}
http://www.csdn.net/develop/Read_Article.asp?Id=9825
实用中都得建立连接池?
有这样的例子吗?谢谢