# How can I connect to CrateDB using JDBC? **URL:** \ **Category:** 3rd Party Tools\ **Created:** [May 21, 2020, 6:16pm UTC](https://community.cratedb.com/t/how-can-i-connect-to-cratedb-using-jdbc/400 "2020-05-21T18:16:25Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![miguel.arregui](https://sea2.discourse-cdn.com/flex020/user_avatar/community.cratedb.com/miguel.arregui/32/126_2.png) [@miguel.arregui](https://community.cratedb.com/u/miguel.arregui)\ **Post date:** [May 21, 2020, 6:16pm UTC](https://community.cratedb.com/t/how-can-i-connect-to-cratedb-using-jdbc/400/1 "2020-05-21T18:16:25Z")
1- how can I connect to crateDB using jdbcjar? 2- do we have a jdbc connection string? ---
**Author:** ![hackerwin7](https://sea2.discourse-cdn.com/flex020/user_avatar/community.cratedb.com/hackerwin7/32/161_2.png) [@hackerwin7](https://community.cratedb.com/u/hackerwin7)\ **Post date:** [May 24, 2020, 1:16pm UTC](https://community.cratedb.com/t/how-can-i-connect-to-cratedb-using-jdbc/400/2 "2020-05-24T13:16:40Z")
```auto Class.forName("io.crate.client.jdbc.CrateDriver"); System.out.println("staring to connect..."); Properties props = new Properties(); props.put("user", "crate"); Connection conn = DriverManager.getConnection("crate://127.0.0.1:4200/", props); ``` this will hangs on `DriverManager.getConnection` crate versino is 4.1.5 crate-jdbc version is 2.6.0 ---
**Author:** ![smu](https://sea2.discourse-cdn.com/flex020/user_avatar/community.cratedb.com/smu/32/60_2.png) [@smu](https://community.cratedb.com/u/smu)\ **Post date:** [May 25, 2020, 7:54am UTC](https://community.cratedb.com/t/how-can-i-connect-to-cratedb-using-jdbc/400/3 "2020-05-25T07:54:32Z")
Use the correct port for the postgresql protocol `5432` like documented here: [https://crate.io/docs/jdbc/en/latest/connect.html](https://crate.io/docs/jdbc/en/latest/connect.html). ---
**Author:** ![miguel.arregui](https://sea2.discourse-cdn.com/flex020/user_avatar/community.cratedb.com/miguel.arregui/32/126_2.png) [@miguel.arregui](https://community.cratedb.com/u/miguel.arregui)\ **Post date:** [May 31, 2020, 5:41pm UTC](https://community.cratedb.com/t/how-can-i-connect-to-cratedb-using-jdbc/400/4 "2020-05-31T17:41:15Z")
Hi @hackerwin7, I hope you are well. Yes, the [reference](https://crate.io/docs/jdbc/en/latest/connect.html) is correct and you will need [our driver](https://github.com/crate/crate-jdbc). [Latest release of our JDBC driver](https://github.com/crate/crate-jdbc/releases). Just to make sure it is clear, I am going to walk you through the most generic postgres wire protocol centric way, and will I assume that you understand your way around a terminal command line and have a JDK installed and setup in your environment. 1. Take the following snippet and save it to a file `PostgresProtocolWireSolo.java`: ```auto import java.sql.ResultSet; import java.sql.Connection; import java.sql.Statement; import java.sql.DriverManager; import java.sql.ResultSetMetaData; import java.util.Locale; import java.util.Properties; public class PostgresProtocolWireSolo { public static final int SO_RCVBUF = 1024 * 1024; // 1 MB public static final int MAX_BATCH_SIZE = 20000; public static final int QUERY_EXECUTION_TIMEOUT_SECS = 60; public static void main(String[] args) throws Exception { // In CrateDB: // // create table t (c0 int primary key, c1 text); // insert into t values(0, 'zero'), (1, 'one'), (2, 'two'); String connectionUrl = "jdbc:postgresql://localhost:5432/"; Properties connectionProps = new Properties(); // https://jdbc.postgresql.org/documentation/head/connect.html connectionProps.put("user", "crate"); connectionProps.put("password", ""); connectionProps.put("ssl", false); connectionProps.put("recvBufferSize", SO_RCVBUF); connectionProps.put("defaultRowFetchSize", MAX_BATCH_SIZE); connectionProps.put("loginTimeout", 5); // seconds, fail fast-ish connectionProps.put("socketTimeout", QUERY_EXECUTION_TIMEOUT_SECS); connectionProps.put("tcpKeepAlive", true); try (Connection sqlConnection = DriverManager.getConnection(connectionUrl, connectionProps)) { sqlConnection.setAutoCommit(true); if (sqlConnection.isClosed()) { System.out.println("Connection is not valid"); return; } try(Statement stmt = sqlConnection.createStatement()) { boolean checkResults = stmt.execute("select * from t"); if (checkResults) { ResultSet rs = stmt.getResultSet(); while(rs.next()) { ResultSetMetaData metaData = rs.getMetaData(); int columnCount = metaData.getColumnCount(); for (int i = 1; i <= columnCount; i++) { System.out.printf( Locale.ENGLISH, ">> col %d: %s: %s\n", i, metaData.getColumnName(i), rs.getObject(i)); } } } } } } } ``` 1. From a terminal window, at the same path where the file is, compile it: ```auto javac PostgresProtocolWireSolo.java ``` Notice that I like to be up to date with my java: ```auto javac --version javac 14 java --version java 14 2020-03-17 Java(TM) SE Runtime Environment (build 14+36-1461) Java HotSpot(TM) 64-Bit Server VM (build 14+36-1461, mixed mode, sharing) ``` 1. Now you need the appropriate JDBC driver, in jar format. You can copy the url (in the code snippet below) and paste it in a browser to get the file, or you can run the curl command, the important thing is that the jar file ends up right next to the `PostgresProtocolWireSolo.class` file generated in step 2: ```auto curl --output pgql42_2_12.jar https://repo1.maven.org/maven2/org/postgresql/postgresql/42.2.12/postgresql-42.2.12.jar ``` 1. Make sure CrateDB is up and running. Notice that in the source code, it expects to find a socket listener at the other end, on port `5432`. Sometimes I have postgres running in my host, and when I launch CrateDB, the default port 5432 will be already taken, thus CrateDB will bind to 5433 instead. This information will be available in CrateDB’s start logs, something like: ```auto [2020-05-31T10:41:57,403][INFO][psql] [Zwölferkogel] publish_address {127.0.0.1:5433}, bound_addresses {[::1]:5432}, {127.0.0.1:5432} ``` 1. With CrateDB up and running, use your favourite client to create a table and insert some data: ```auto create table t (c0 int primary key, c1 text); insert into t values(0, 'zero'), (1, 'one'), (2, 'two'); ``` 1. Run the program: ```auto java -cp pgql42_2_12.jar:. PostgresProtocolWireSolo >> col 1: c0: 1 >> col 2: c1: one >> col 1: c0: 2 >> col 2: c1: two >> col 1: c0: 0 >> col 2: c1: zero ``` Once the steps above are understood and you have the show running, you should fall back to our [driver jar](https://crate.io/docs/jdbc/en/latest/index.html), as described in the reference. Kind regards, ---
**Author:** ![amotl](https://sea2.discourse-cdn.com/flex020/user_avatar/community.cratedb.com/amotl/32/617_2.png) [@amotl](https://community.cratedb.com/u/amotl)\ **Post date:** [August 20, 2021, 10:50am UTC](https://community.cratedb.com/t/how-can-i-connect-to-cratedb-using-jdbc/400/5 "2021-08-20T10:50:12Z")
Hi again, I took the code example provided by Miguel as a blueprint and just added it to [cratedb-examples/spikes/jdbc-basic at main · crate/cratedb-examples · GitHub](https://github.com/crate/cratedb-examples/tree/main/spikes/jdbc-basic), which now provides a full and concise example program plus some guidelines outlining how to connect to CrateDB using both the vanilla [PgJDBC Driver](https://jdbc.postgresql.org/) and the [CrateDB JDBC Driver](https://github.com/crate/crate-jdbc). With kind regards, Andreas.