CODEWITHSUNDEEP
javasql-serversql-server-2008jdbc
MrProper
MrProper

Reputation: 1580

Problems logging into MSSQL server from Java

I am trying to connect to MSSQL server 2008 on my localhost, but I am getting Errors

WARNING: ConnectionID:2 Prelogin error: host 127.0.0.1 port 1434 Error reading prelogin response: Connection reset

this error repeats like 20 times very quickly, then i get com.microsoft.sqlserver.jdbc.SQLServerException: Connection reset

I suspect this is some wrong configuration of server. I can connect to external servers with no issues. I can also connect via management studio with no problems.

Please help me, I am getting sick of this issue :|

Upvotes: 4

Views: 18978

Answers (3)

Andrei Luksha
Andrei Luksha

Reputation: 1030

In my case this error got resolved by increasing loginTimeout in JDBC properties. The value is configured in seconds.

The default value is:

  • 30 (version 11.2 and up)
  • 15 for (version 10.2 and below)

More about timeouts: https://learn.microsoft.com/en-us/sql/connect/jdbc/understand-timeouts?view=sql-server-ver16

For the initial connection, loginTimeout is used:

loginTimeout is the amount of time, in seconds, the driver waits to establish a connection to the server. If this amount is exceeded, an error is returned, and no open connection is established. A zero value indicates that the timeout is the default system timeout, which is 30 seconds in versions 11.2 and above. For versions 10.2 and below, the default timeout is 15 seconds. Any nonzero value is the number of seconds the driver should wait before timing out a failed connection. If you're consistently having trouble establishing a connection with the JDBC driver, you may need to increase this timeout to 90, or even 120, seconds.

More about configuring JDBC properties in SQL Server driver: https://learn.microsoft.com/en-us/sql/connect/jdbc/setting-the-connection-properties?view=sql-server-ver16

Upvotes: 0

Shahriar Nour
Shahriar Nour

Reputation: 3

To connect to MSSQL Server from a Java application, you need to use the JDBC API. The JDBC API provides classes and methods that connect to the database, load the appropriate driver, send SQL queries, retrieve results etc.

HOW TO CONNECT TO THE DATABASE A ‘Connection’ object represents a connection with a database. To establish the connection, use the method ‘DriverManager.getConnection’. This method takes a string containing a URL which represents the database we are trying to connect to. Below is the sample code for establishing a connection:

private String DATABASE_URL = "jdbc:odbc:embedded_sql_app"; // establish connection to database
Connection connection = DriverManager.getConnection( DATABASE_URL,"sa","123" );

Detailed discussion about the Database URL and how to create it can be found in the resource provided at the end of this post.

QUERYING THE DATABASE The JDBC API provides three interfaces for sending SQL statements to the database, and corresponding methods in the ‘Connection’ interface create instances of them. 1. Statement - created by the ‘Connection.createStatement’ methods. A ‘Statement’ object is used for sending SQL statements with no parameters. 2. PreparedStatement - created by the ‘Connection.prepareStatement methods’. A ‘PreparedStatement’ object is used for precompiled SQL statements. These can take one or more parameters as input arguments (IN parameters). 3. CallableStatement - created by the ‘Connection.prepareCall’ methods. ‘CallableStatement’ objects are used to execute SQL stored procedures from Java database applications.

RETRIEVING THE RESULT A ‘ResultSet ‘is a Java object that contains the results of executing a SQL query. The data stored in a ‘ResultSet’ object is retrieved through a set of get methods that allows access to the various columns of the current row. The ‘ResultSet.next’ method is used to move to the next row of the ‘ResultSet’, making it the current row. The following code fragment executes a query that returns a collection of rows, with column ‘a’ as an ‘int’, column ‘b’ as a ‘String’, and column ‘c’ as a ‘float’:

java.sql.Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("SELECT a, b, c FROM Table1");
while (rs.next()) { // retrieve and print the values for the current row
int i = rs.getInt("a");
String s = rs.getString("b");
float f = rs.getFloat("c");
System.out.println("ROW = " + i + " " + s + " " + f); }

This is just a brief introduction on how to interact with a database from Java. For more details on the items discussed above as well as information on passing parameters, executing stored procedures etc. please refer to the following resource: ( http://www.shahriarnk.com/Shahriar-N-K-Research-Embedding-SQL-in-C-Sharp-Java.html#Shahriar_N_Embedding_SQL_in_Java ) Here, you will also find information on how to interact with a database programmatically; i.e. without using SQL. Hope you find this useful.

Upvotes: -4

paulsm4
paulsm4

Reputation: 121599

1) TCP protocol for MSSQL 2008 is disabled by default. You need to enable it from SQL Configuration Manager (in the same [Start], Programs folder as MSSQL):

2) To use TCP connections (even on localhost!) you need to allow MSSQL in Windows Firewall:

3) You don't necessarily need to use TCP/IP in order to access MSSQL:

'Hope that helps!

Upvotes: 7

Related Questions