java的mysqlhelper类如何释放连接池
发布网友
发布时间：2022-04-08 04:07
我来回答
共2个回答
懂视网
时间：2022-04-08 08:29
System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;
using System.Data.SqlClient;
using System.Data;
namespace MySqlHelper
{
public class SQLHelper
{
private static readonly string connstr = ConfigurationManager.ConnectionStrings["connstr"].ConnectionString;
/// <summary>
/// 连接数据库
/// </summary>
/// <returns></returns>
public static SqlConnection CreateConnection()
{
SqlConnection conn = new SqlConnection(connstr);
conn.Open();
return conn;
}
/// <summary>
/// 返回受影响行数
/// </summary>
/// <param name="conn"></param>
/// <param name="sql"></param>
/// <param name="parameters"></param>
/// <returns></returns>
public static int ExecuteNonQuery(SqlConnection conn, string sql, params SqlParameter[] parameters)
{
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = sql;
cmd.Parameters.AddRange(parameters);
return cmd.ExecuteNonQuery();
}
}
/// <summary>
/// 按现有连接，返回受影响行数
/// </summary>
/// <param name="sql"></param>
/// <param name="parameters"></param>
/// <returns></returns>
public static int ExecuteNonQuery(string sql, params SqlParameter[] parameters)
{
using (SqlConnection conn = CreateConnection())
{
return ExecuteNonQuery(conn,sql,parameters);
}
}
/// <summary>
/// 返回第一行第一条数据
/// </summary>
/// <param name="conn"></param>
/// <param name="sql"></param>
/// <param name="parameters"></param>
/// <returns></returns>
public static object ExecuteScalar(SqlConnection conn, string sql, params SqlParameter[] parameters)
{
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = sql;
cmd.Parameters.AddRange(parameters);
return cmd.ExecuteScalar();
}
}
/// <summary>
/// 按现有连接，返回第一行第一条数据
/// </summary>
/// <param name="sql"></param>
/// <param name="parameters"></param>
/// <returns></returns>
public static object ExecuteScalar(string sql, params SqlParameter[] parameters)
{
using (SqlConnection conn = CreateConnection())
{
return ExecuteScalar(conn,sql,parameters);
}
}
/// <summary>
/// 返回多条数据
/// </summary>
/// <param name="conn"></param>
/// <param name="sql"></param>
/// <param name="parameters"></param>
/// <returns></returns>
public static DataTable ExecuteReader(SqlConnection conn, string sql, params SqlParameter[] parameters)
{
DataTable table = new DataTable();
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = sql;
cmd.Parameters.AddRange(parameters);
using (SqlDataReader reader = cmd.ExecuteReader())
{
table.Load(reader);
}
}
return table;
}
/// <summary>
/// 按现有连接，返回多条数据
/// </summary>
/// <param name="sql"></param>
/// <param name="parameters"></param>
/// <returns></returns>
public static DataTable ExecuteReader(string sql, params SqlParameter[] parameters)
{
using (SqlConnection conn = CreateConnection())
{
return ExecuteReader(conn,sql,parameters);
}
}
}
}
Web.config配置文件:
<configuration>
<system.web>
<compilation debug="true" targetFramework="4.5" />
<httpRuntime targetFramework="4.5" />
</system.web>
<connectionStrings>
<add name="connstr" connectionString="server=PC-20140729GKIU;user id=sa;password=update123;database=sy"/>
</connectionStrings>
</configuration>
MySqlHelper
标签：
热心网友
时间：2022-04-08 05:37
public ResultSet SQL_ExecuteQuery(String sql,Object [] p){
Connection con=openConnection();//打开数据库
PreparedStatement pst=null;//定义一个 执行对象
try {
pst=con.prepareStatement(sql);//初始化执行对象
//循环设置参数
if(p!=null && p.length>0){
for (int i = 0; i < p.length; i++) {
pst.setObject((i+1), p[i]);//设置参数
}
}
//最后执行命令 并返回结果
return pst.executeQuery();//执行命令
} catch (SQLException e) {
e.printStackTrace();
}finally{
try{pst.close();}catch(SQLException ex){}
try{con.close();}catch(SQLException ex){}
}
return null;
}
百度搞得乱乱的，，，，，
追问不行，这样的会报nullpointer错误
追答//最后执行命令 并返回结果
return pst.executeQuery();//执行命令
换成，返回Vector>
