java 使用Sql数据库代码

import java.sql.*;

public class SqlHelper {

// 测试连接函数
public static void main(String []args)
{
derbyHelper de=new derbyHelper();
String sql="select * from users";

List<Object[]> list=de.queryList(sql, null);
for(int i=0;i<list.size();i++)
{ Object []obj=list.get(i);
System.out.println(obj[1].toString()+" "+obj[2].toString());
}

}

String driver="com.microsoft.sqlserver.jdbc.SQLServerDriver";
String url="jdbc:sqlserver://192.168.1.109:142;databaseName=QqDB";
// String url="jdbc:sqlserver://10.62.149.195:142;databaseName=QqDB";

String user="sa";
String passwd="bbc223344";
Connection ct;
PreparedStatement ps;
ResultSet rs;
public SqlHelper()
{
try {
Class.forName(driver);
ct=DriverManager.getConnection(url,user,passwd);

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public int Update(String sql,String []paras)
{
int count=0;
try {
ps=ct.prepareStatement(sql);
for(int i=0;i<paras.length;i++)
{
ps.setString(i+1, paras[i]);
}
count=ps.executeUpdate() ;

} catch (SQLException e) {
// TODO Auto-generated catch block
if(e.getErrorCode()==2627)
count=2;//插入重复建。

e.printStackTrace();
}finally{
this.close();
}



return count;
}

public ResultSet query(String sql,String[] paras)
{
try {
ps=ct.prepareStatement(sql);
for(int i=0;i<paras.length;i++)
{
ps.setString(i+1, paras[i]);
}
rs=ps.executeQuery();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
//不能关。
}


return rs;
}
public void close()
{

try {
if(rs!=null) rs.close();
if(ps!=null) ps.close();
if(ct!=null) ct.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}
}