通用的DAO类

import java.util.*;
import java.sql.*;
import javax.servlet.jsp.jstl.sql.*;

public class SQLCommandBean {
private Connection conn;
private String sqlValue;
private List values;

//设定连接类
public void setConn(Connection conn) {
this.conn = conn;
}
//设定sql语句
public void setSqlValue(String sqlValue) {
this.sqlValue = sqlValue;
}
//设定sql语句的参数
public void setValues(List values) {
this.values = values;
}


//执行查询
public Result executeQuery() throws SQLException{
Result result=null;
ResultSet rs=null;
PreparedStatement pstmt=null;
Statement stmt=null;
try{
if(values!=null&&values.size()>0)
{
pstmt=conn.prepareStatement(sqlValue);
setValues(pstmt,values);
rs=pstmt.executeQuery();
}
else
{
stmt=conn.createStatement();
rs=stmt.executeQuery(sqlValue);
}
result=ResultSupport.toResult(rs);
}
finally{

if(rs!=null)
{
try{rs.close();}catch(SQLException e){}
}
if(stmt!=null)
{
try{stmt.close();}catch(SQLException e){}
}

if(pstmt!=null)
{
try{pstmt.close();}catch(SQLException e){}
}
}
return result;
}

//执行Update语句
public int executeUpdate() throws SQLException{
int noOfRows=0;
ResultSet rs=null;
PreparedStatement pstmt=null;
Statement stmt=null;
try
{
if(values!=null&&values.size()>0)
{
pstmt=conn.prepareStatement(sqlValue);
setValues(pstmt,values);
noOfRows=pstmt.executeUpdate();
}
else
{
stmt=conn.createStatement();
noOfRows=stmt.executeUpdate(sqlValue);
}
}finally
{

if(rs!=null)
{
try{rs.close();}catch(SQLException e){}
}
if(stmt!=null)
{
try{stmt.close();}catch(SQLException e){}
}

if(pstmt!=null)
{
try{pstmt.close();}catch(SQLException e){}
}
}
return noOfRows;
}
//设定语句参数
private void setValues(PreparedStatement pstmt,List values)
throws SQLException {
for(int i=0;i<values.size();i++)
{
Object v=values.get(i);
pstmt.setObject(i+1, v);
}
}

}